Hepatitis autoinmune seronegativa / Seronegative autoimmune hepatitis

Resumen La hepatitis autoinmune (HAI) es una enfermedad inflamatoria y necrótica del hígado, crónica e infre cuente caracterizada por la presencia de autoanti cuerpos. Su etiología es desconocida. Afecta a 1 de cada 200 000 personas anualmente en los EE. UU. y se presenta predominantemente en mujeres. Su presenta ción varía desde formas asintomáticas hasta la cirrosis y falla hepática aguda y su diagnóstico se basa en la medición de autoanticuerpos, como los autoanticuer pos antinucleares (ANA), anticuerpos antimúsculo liso (ASMA) y anticuerpos antimicrosomales de hígado y riñón (anti-LKM-1). El 10% de las HAI no presentan anti cuerpos, denominándose HAI seronegativa, necesitando biopsia hepática para el diagnóstico. Hasta la fecha la evidencia sigue siendo limitada y diferentes sociedades han emitido sugerencias y recomendaciones. Por tal motivo creemos relevante realizar una revisión biblio gráfica sobre el tema plasmando en este documento la información importante para la compresión y el manejo de esta patología.

Abstract Autoimmune hepatitis (AIH) is a rare, chronic, inflam matory, and necrotic liver disease characterized by the presence of autoantibodies. Its etiology is unknown. It affects 1 in 200 000 people annually in the US and oc curs predominantly in women. Its presentation varies from asymptomatic forms to cirrhosis and acute liver failure and its diagnosis is based on the measurement of autoantibodies, such as antinuclear autoantibod ies (ANA), anti-smooth muscle antibodies (ASMA) and anti-liver and kidney microsomal antibodies (anti-LKM). 1). 10% of HAIs do not present antibodies, being called seronegative HAI, requiring a liver biopsy for diagnosis. To date the evidence remains limited and different so cieties have issued suggestions and recommendations. For this reason, we believe it is relevant to carry out a bibliographic review on the subject, capturing in this document the important information for the under standing and management of this pathology.

Pattern of prescription drugs used for patients diagnosed with systemic vasculitis / Patrón de prescripción de medicamentos utilizados en pacientes con diagnóstico de vasculitis sistémicas

ABSTRACT Introduction: Vasculitis is a heterogeneous group of diseases characterized by inflammation of the blood vessel wall, which can cause thrombosis, stenosis, or occlusion. Its pharmacological management involves corticosteroids and conventional and biological disease-modifying antirheumatic drugs. Objectives: The objective was to determine the different types of systemic vasculitis and their pharmacological treatment in a group of patients from Colombia, 2019-2020. Materials and methods: This was a cross-sectional study that identified different types of systemic vasculitis and their pharmacological management in a group of patients from a drug-dispensing database of approximately 8.5 million people. Sociodemographic, comorbidity and pharmacological variables were considered. A descriptive analysis was performed. Results: A total of 621 patients with a diagnosis of systemic vasculitis were identified. The patients had a median age of 55.0 years, and 74.4% were women. The most common vasculitis types were those limited to the skin (30.1%), granulomatosis with polyangiitis (17.6%), and necrotizing vasculopathy (10.8%). A total of 81.0% of cases received corticosteroid prescriptions, 44.0% received azathioprine, and 24.0% received methotrexate; only 1.6% were prescribed biological antirheumatic drugs. Cardiovascular diseases were the most common comorbidity. Conclusions: The pattern of prescription medications used for patients diagnosed with systemic vasculitis is heterogeneous. Much of this population has associated comorbidities, which increases the use of medications according to the current management guidelines.

RESUMEN Introducción: Las vasculitis son un grupo heterogéneo de enfermedades caracterizadas por la inflamación de la pared de los vasos sanguíneos, lo cual puede llegar a ocasionar trombosis, estenosis u oclusión. Su manejo farmacológico incluye corticoesteroides, antirreumáticos modificadores de enfermedad convencionales y biológicos. Objetivos: El objetivo de este estudio fue determinar los diferentes tipos de vasculitis sistémicas y su tratamiento farmacológico en un grupo de pacientes de Colombia. Materiales y métodos: Se trató de un estudio de corte transversal que identificó los diferentes tipos de vasculitis sistémicas y su manejo farmacológico en un grupo de pacientes, a partir de una base de datos de dispensación de medicamentos de aproximadamente 8,5 millones de personas. Se consideraron variables sociodemográficas, comorbilidades y variables farmacológicas, y se hizo un análisis descriptivo. Resultados: Se identificaron 621 pacientes con diagnóstico de vasculitis sistémicas, con una mediana de edad de 55,0 anos, el 74,4% mujeres, siendo las vasculitis más frecuentes las limitadas a la piel (30,1%), la granulomatosis con poliangeitis (17,6%) y la vasculopatía necrosante (10,8%). El 81,0% de los casos recibió corticoesteroides, el 44,0% azatioprina y el 24,0 metotrexate, mientras que solo el 1,6% tenía prescritos antirreumáticos biológicos. Las comorbilidades cardiovasculares fueron las más comunes. Conclusiones: El patrón de prescripción de medicamentos utilizados en pacientes con diagnóstico de vasculitis sistémicas es heterogéneo y acorde con las guías actuales de manejo. Gran parte de esta población cursa con comorbilidades asociadas, lo cual incrementa el uso de medicamentos.

Evolución clínica en neuromielitis óptica comparando el manejo con azatioprina o rituximab / Clinical evolution in neuromyelitis optica when comparing management with azathioprine and rituximab

RESUMEN INTRODUCCIÓN: El espectro de trastornos de neuromielitis óptica (NMOSD) es un grupo de enfermedades desmielinizantes, inflamatorias y autoinmunes, caracterizadas por episodios recurrentes de neuritis óptica y mielitis transversa longitudinal extensa, entre otras manifestaciones clínicas. Su tratamiento crónico se basa en el uso de terapias inmunosupresoras como azatioprina (AZA), micofenolato mofetilo (MFM) o rituximab (RTX). El objetivo del presente estudio es realizar un análisis comparativo de la respuesta al tratamiento con AZA o RTX. MATERIALES Y MÉTODOS: Se realizó un estudio observacional, analítico, retrospectivo, en el cual se incluyeron inicialmente 69 pacientes con diagnóstico confirmado de NMOSD. Tras aplicar los criterios de inclusión y exclusión 59 pacientes fueron incluidos en el análisis final. RESULTADOS: En el grupo de RTX se evidenció una mejoría importante en el estado funcional en comparación con el grupo de AZA, en el que se vio un empeoramiento de este al año de seguimiento. El perfil de seguridad fue similar entre ambos grupos, con una adherencia significativamente superior en el grupo de RTX. DISCUSIÓN: Los hallazgos del presente estudio respecto a las ventajas del uso de RTX sobre AZA se encuentran en concordancia con resultados de estudios previos reportados en la literatura. CONCLUSIONES: Los resultados respaldan el uso de RTX sobre AZA como terapia de mantenimiento para pacientes con NMOSD, al estar asociado principalmente con una mejoría notable en la funcionalidad de los pacientes, al igual que una mayor adherencia al tratamiento.

ABSTRACT INTRODUCTION: Neuromyelitis Optica Spectrum Disorders (NMOSD) is a group of inflammatory, autoimmune, and demyelinating disorders. Its hallmark behavior is characterized by recurrent episodes of optic neuritis and longitudinally extensive transverse myelitis, among other clinical manifestations. Chronic therapy is based primarily in immunosuppressive therapies such as azathioprine (AZA), mycophenolate mofetil (MMF), or rituximab (RTX). The goal of this study is to perform a comparative analysis of response rates to chronic treatment with either AZA or RTX. MATERIALS AND METHODS: A retrospective observational analytic study was designed with an initial cohort of 69 patients with a diagnosis of NMOSD. After application of the inclusion and exclusion criteria a total of 59 patients were finally included in the analysis. RESULTS: The RTX group had an improved functional status when compared to the AZA group; in the latter this feature worsened after a one-year follow-up. There was also a comparable safety profile between the two groups with a significantly greater adherence to RTX regimes. DISCUSSION: The findings of the current study as to the benefits of RTX in comparison to AZA are similar to the results of previous studies. CONCLUSION: These results favor the use of RTX as maintenance treatment of NMOSD, because of its greater benefit mainly in the improvement in functional status of patients, as well as a greater adherence to treatment.

Long-term safety of azathioprine for treatment of neuromyelitis optica spectrum disorders / Segurança a longo prazo da azatioprina no tratamento dos transtornos do espectro da neuromielite óptica

ABSTRACT Background: Azathioprine is a common first-line therapy for neuromyelitis optica spectrum disorder (NMOSD). Objective: The aim of this study was to determine whether long-term treatment (>10 years) with azathioprine is safe in NMOSD. Methods: We conducted a retrospective medical record review of all patients at the School of Medicine of the University of São Paulo (São Paulo, Brazil) who fulfilled the 2015 international consensus diagnostic criteria for NMOSD and were treated with azathioprine for at least 10 years. Results: Out of 375 patients assessed for eligibility, 19 were included in this analysis. These patients' median age was 44 years (range=28-61); they were mostly female (17/19) and AQP4-IgG seropositive (18/19). The median disease duration was 15 years (range=10-39) and most patients presented a relapsing clinical course (84.2%). The median duration of treatment was 11.9 years (range=10.0-23.8). The median annualized relapse rates (ARR) pre- and post-treatment with azathioprine were 1 (range=0.1-2) and 0.1 (range=0-0.35); p=0.09. Three patients (15.7%) had records of adverse events during the follow-up, which consisted of chronic B12 vitamin deficiency, pulmonary tuberculosis and breast cancer. Conclusion: Azathioprine may be considered a safe agent for long-term treatment (>10 years) of NMOSD, but continuous vigilance for infections and malignancies is required.

RESUMO Introdução: A azatioprina é um tratamento comum de primeira linha para os transtornos do espectro neuromielite óptica (NMOSD). Objetivo: Este estudo visou determinar a segurança do tratamento a longo prazo (>10 anos) da NMOSD com a azatioprina. Métodos: Foi realizada revisão retrospectiva de todos os prontuários de pacientes que preenchiam critérios de NMOSD de acordo com o "International Consensus Diagnostic Criteria for NMOSD" de 2015 em uso de azatioprina por ao menos 10 anos matriculados no ambulatório de Doenças Desmielinizantes do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Resultados: De 375 pacientes avaliados, 19 preencheram critérios de inclusão para análise. A mediana de idade foi de 44 anos (variância=28-61); os pacientes eram predominantemente do sexo feminino (17/19) e AQP4-IgG soropositivos (18/19). A mediana do tempo de duração de doença foi 11,9 anos (variância=10,0-23,8), a mediana da taxa anualizada de surtos pré e pós-tratamento foi de 1 (variância=0,1-2) e 0,1 (variância=0-0,35), p=0,09. Três pacientes (15,7%) apresentaram registro de eventos adversos durante o seguimento: deficiência crônica de vitamina B12, tuberculose pulmonar e câncer de mama. Conclusão: A azatioprina provavelmente pode ser considerada segura para o tratamento a longo prazo (>10 anos) da NMOSD, porém vigilância contínua de neoplasias e infecções é necessária.

Nodular anterior scleritis associated with Berger's disease / Esclerite anterior nodular associada à doença de Berger

ABSTRACT A 45-year-old female patient presented with a complaint of right eye redness and pain for 7 days. She was under investigation for urinary abnormalities and reported a previous history of recurrent oral ulcers and ocular hyperemia in both eyes. Best-corrected visual acuity was 20/30 and 20/20 in the right and left eyes, respectively. Slit-lamp biomicroscopy of the ocular surface of the right eye revealed nasal scleral hyperemia that persisted after instillation of topical phenylephrine 10%, reinforcing the diagnosis of anterior scleritis. Renal biopsy showed immunoglobulin A immune complexes and confirmed the suspected diagnosis of Berger's disease. Maintenance immunosuppressive therapy with azathioprine following a 6-month induction of remission with cyclophosphamide was necessary after pulse therapy with methylprednisolone. Scleritis is usually related to systemic autoimmune diseases, such as rheumatoid arthritis, and polyangiitis. Herein, we describe a rare case of unilateral anterior scleritis associated with Berger's disease.

RESUMO Paciente de 45 anos, sexo feminino queixava-se de hiperemia e dor no olho direito há sete dias. Encontrava-se sob investigação de alterações urinárias e relatou história pregressa de úlceras orais e hiperemia ocular bilateral recorrentes. A acuidade visual corrigida era de 20/30 no olho direito e 20/20 no esquerdo. A biomicroscopia da superfície ocular do olho direito revelou intensa hiperemia escleral em região nasal que persistiu após a instilação de fenilefrina tópica a 10%, reforçando o diagnóstico clínico de esclerite anterior unilateral. A biópsia renal revelou a presença de imunocomplexos de IgA e confirmou a hipótese de doença de Berger. Uma terapia imunossupressora de manutenção com azatioprina após 6 meses de indução de remissão com ciclofosfamida foi necessária após pulsoterapia com metilprednisolona. A esclerite geralmente está relacionada a doenças autoimunes sistêmicas, como artrite reumatoide e poliangeite. Descrevemos aqui um caso raro de esclerite anterior unilateral associada à doença de Berger.

Efficacy and safety of dupilumab in two adolescents with severe atopic dermatitis / Eficácia e segurança do uso de dupilumabe em dois adolescentes com dermatite atópica grave

ABSTRACT We report the cases of two adolescent siblings with severe atopic dermatitis, who, despite weighing approximately 40kg, presented a good response to dupilumab with the off-label dose for individuals aged 12 years and weighing 60kg. Both had already used cyclosporine, azathioprine, methotrexate and oral corticosteroids for long periods, plus topical treatments with no adequate disease control. Skin lesions were constant and widespread, with frequent skin infections and very poor quality of life, with numerous physical and psychosocial consequences, such as dropping out of school activities due to severe itching, appearance and bullying. They also showed delayed growth and development. In 2018, dupilumab, an immunobiological agent, was approved for treatment of moderate to severe atopic dermatitis in adults and, in 2019, extended to the 12-17-year age group. Although it had already been approved by the Brazilian Health Surveillance Agency, the 200mg presentation (indicated for the weight of patients) was not available, with no expected arrival date. Therefore, weighing the risks and benefits of the situation of both, we chose to treat them with an adult dose (loading dose of 600mg subcutaneously, and 300mg subcutaneously every 2 weeks) despite the low weight. So far, they have received eight injections, showing significant improvement of disease and quality of life. There were no major adverse effects, only worsening of allergic conjunctivitis in one of them. The patients and their family are very satisfied, and we believe that the therapy has been successful.

RESUMO Relatamos os casos de dois irmãos adolescentes com dermatite atópica grave e que, apesar de pesarem cerca de 40kg, apresentaram boa resposta ao dupilumabe com a dose off-label para indivíduos com 12 anos e peso de 60kg. Ambos já tinham usado ciclosporina, azatioprina, metotrexato e corticoide oral por longos períodos, acrescidos de tratamentos tópicos sem controle adequado da doença. As lesões cutâneas eram constantes e disseminadas, e os irmãos apresentavam infeções de pele frequentes e qualidade de vida muito ruim, com inúmeras consequências físicas e psicossociais, como o abandono da atividade escolar pelo prurido intenso, pela aparência e pelo bullying sofrido. Apresentavam também retardo de crescimento e de desenvolvimento. Em 2018, o dupilumabe, um agente imunobiológico, foi aprovado para o tratamento de dermatite atópica moderada a severa para adultos e, em 2019, ampliado para faixa etária de 12 a 17 anos. Embora já tivesse a aprovação da Agência Nacional de Vigilância Sanitária no Brasil, a apresentação de 200mg (indicada para o peso dos pacientes) não estava disponível, sem previsão de chegada. Assim, pesando os riscos e benefícios da situação de ambos, optamos por tratá-los com dose de adulto (ataque de 600mg por via subcutânea e 300mg por via subcutânea a cada 2 semanas) apesar do baixo peso. Até o momento, eles realizaram oito aplicações, apresentando importante melhora da doença e da qualidade de vida. Não houve efeitos adversos importantes - apenas a piora da conjuntivite alérgica em um deles. Os pacientes e sua família estão muito satisfeitos, e nós avaliamos que a terapia está sendo bem-sucedida.

Hepatotoxicidade induzida por azatioprina em portadora da síndrome de Vogt-Koyanagi-Harada / Azathioprine-induced hepatotoxicity in a Vogt-Koyanagi-Harada syndrome patient

Este relato teve como objetivo apresentar um caso de hepatotoxicidade colestática induzida por azatioprina em portadora da síndrome de Vogt-Koyanagi-Harada. À admissão, apresentava icterícia +3/+4, acolia fecal e colúria, além de aumento de marcadores hepáticos, sendo compatível com síndrome colestática, cuja etiologia foi confirmada após exclusão de outras causas possíveis e retirada da azatioprina. A paciente evoluiu, após 1 semana de retirada do fármaco, com diurese livre de coloração menos escura e evacuação presente, sem acolia. Além disso, houve melhora nos exames que precederam a alta hospitalar

This report aimed at presenting a case of azathioprine-induced cholestatic hepatotoxicity in a patient with Vogt-Koyanagi-Harada syndrome. On admission, she presented with jaundice +3/+4, acholic feces, and choluria, as well as increased hepatic markers, all consistent with cholestatic syndrome, the etiology of which was confirmed after other possible causes were ruled out and azathioprine was discontinued. After 1 week of the drug discontinuation, the patient progressed with free diuresis of lighter color and defecation, with no acholia. In addition, tests performed before discharge were improved.

Clinical and laboratory data in pediatric autoimmune hepatitis: study from referral center in Iran / Datos clínicos y de laboratorio en hepatitis autoinmune pediátrica: estudio del centro de referencia en Irán

ABSTARCT Background : Autoimmune hepatitis (AIH) is an auto-inflammatory liver disease of children and adults, affecting patients of any age, sex, race or ethnicity, with more prevalence in females. Objective : The aim of this study was to evaluate clinical manifestation, laboratory findings, and outcome of children with autoimmune hepatitis. Materials and methods : We evaluated 86 patients treated and followed with final diagnosis of AIH between years 2010 to 2018. Physical findings (including jaundice, hepatomegaly, splenomegaly and encephalopathy), liver enzymes, liver histology and autoantibodies (including ANA, Anti LKM-1 and ASMA) were extracted from medical files. Then the patients were followed for their final outcome (including response to medical treatment or successful treatment withdrawal, liver transplantation or death). Results : Among 86 patients with AIH with mean age 9.10±4.36 years old, 66.27% were females. Jaundice (75.6%) and hepatomegaly (46.5%) were the most frequent physical findings, followed by splenomegaly (32.6%) and encephalopathy (17.4%). Aminotransferases including AST and ALT were elevated at least 3 times more than upper limit of normal in most of the patients (61.6% and 55.81%, respectively). Autoantibodies were available in 53 of 86 patients, 24.5% had AIH-1, 3.8% had AIH-II and 67.9% were seronegative. Medical treatment including prednisolone and azathioprine was started for patients, 53 of 86 cases (61.6%) had remission and 11 of 86 (13.7%) tolerated medication withdrawal successfully. Among all cases, 26 (30.2%) patients needed liver transplantation. Mortality rate was 9 among 86 cases (10.5%). Conclusion : Jaundice and hepatomegaly was the most frequent clinical findings. Mortality rate was 10.5%.

RESUMEN Antecedentes : La hepatitis autoinmune (AIH) es una enfermedad hepática autoinflamatoria de niños y adultos, que afecta a pacientes de cualquier edad, sexo, raza u origen étnico, con mayor prevalencia en las mujeres. Objetivo : El objetivo de este estudio fue evaluar la manifestación clínica, los hallazgos de laboratorio y el resultado de los niños con hepatitis autoinmune. Materiales y métodos : Evaluamos 86 pacientes tratados y seguidos con el diagnóstico final de AIH entre los años 2010 a 2018. Los hallazgos físicos (incluyendo ictericia, hepatomegalia, esplenomegalia y encefalopatía), enzimas hepáticas, histología hepática y autoanticuerpos (incluidos ANA, Anti LKM-1 y ASMA) se extrajeron de las historias médicas. Luego, los pacientes fueron seguidos para su resultado final (incluida la respuesta al tratamiento médico o la retirada exitosa del tratamiento, el trasplante de hígado o la muerte). Resultados : Entre 86 pacientes con AIH con una edad media de 9,10 ± 4,36 años, el 66,27% eran mujeres. La ictericia (75,6%) y la hepatomegalia (46,5%) fueron los hallazgos físicos más frecuentes, seguidos de esplenomegalia (32,6%) y encefalopatía (17,4%). Las aminotransferasas que incluyen AST y ALT se elevaron al menos 3 veces más que el límite superior de la normalidad en la mayoría de los pacientes (61,6% y 55,81%, respectivamente). Los autoanticuerpos estaban disponibles en 53 de 86 pacientes, 24,5% tenían AIH-1, 3,8% tenían AIH-II y 67,9% eran seronegativos. Se inició tratamiento médico que incluyó prednisolona y azatioprina, 53 de 86 casos (61,6%) tuvieron remisión y 11 de 86 (13,7%) toleraron el retiro de medicamentos con éxito. Entre todos los casos, 26 (30,2%) pacientes necesitaron un trasplante de hígado. La tasa de mortalidad fue de 9 entre 86 casos (10,5%). Conclusión : la ictericia y la hepatomegalia fueron los hallazgos clínicos más frecuentes. La tasa de mortalidad fue del 10,5%.

Comparación entre dos esquemas de inmunosupresión en pacientes con trasplante hepático en un hospital universitario en Medellín, Colombia / Comparison of two immunosuppressive regimens for liver transplant patients in a university hospital in Medellín, Colombia

Introducción. El desarrollo de terapias inmunosupresoras en trasplante hepático ha sido uno de los aspectos fundamentales que ha permitido disminuir la presencia de rechazos y mejorar la supervivencia del injerto y de los pacientes. El presente estudio se hizo para conocer la efectividad de dos esquemas de tratamiento inmunosupresor en una cohorte de pacientes con trasplante hepático, entre 2006 y 2017, en un hospital universitario en Medellín, Colombia. Metodología. Se realizó un estudio observacional retrospectivo donde se compararon dos esquemas de tratamiento inmunosupresor con ciclosporina (CsA) y azatioprina (AZA) versus tacrolimus (TAC) y micofenolato (MMF). Resultados. Se incluyeron 147 pacientes al estudio, 79 mujeres y 68 hombres, con una mediana de edad de 55 años. La tasa de incidencia de rechazo agudo en el grupo CsA/AZA fue de 7,3 y para el grupo TAC/MMF fue de 13,8, con una razón de tasas de 0,53 (IC95%=0,31-0,89) por cada 100 personas/año, siendo esta diferencia estadísticamente significativa (p=0,02). No hubo diferencias significativas entre los grupos con respecto a la presencia de rechazo crónico, supervivencia del injerto o de los pacientes. Con respecto a los efectos adversos asociados al tratamiento, solo hubo diferencia significativa en una mayor presencia de diarrea en el grupo TAC/MMF. Conclusión. Solo se encontró diferencia significativa en cuanto a un número mayor de rechazos agudos en el grupo tratado con TAC/MMF. Estos hallazgos están en concordancia con la experiencia local, en la que en pacientes seleccionados se puede utilizar este esquema, con buenos resultados clínicos y menores costos para el sistema de salud. Hasta el momento, esta es la primera cohorte retrospectiva de Colombia y Latinoamérica que realiza una comparación, como la expuesta.

Introduction. The development of immunosuppressive therapies in liver transplantation has been one of the major contributing factors that have reduced the presence of rejections and improved graft and patient survival. The present study was conducted to determine the effectiveness of two immunosuppressive schemes in a cohort of liver transplant patients, between 2006 and 2017, at a university hospital in Medellin, Colombia. Methodology. A retrospective observational study was performed to compare two immunosuppressive treatment schemes with cyclosporine (CsA) and azathioprine (AZA) versus tacrolimus (TAC) and mycophenolate (MMF). Results. A total of 147 patients were included in the study, 79 women and 68 men, with a median age of 55 years. The incidence rate of acute rejection in the CsA/AZA group was 7.3 while in the TAC/MMF group was 13.8, with a rate ratio of 0.53 (95%CI=0.31-0.89) for every 100 person-year, this difference being statistically significant (p=0.02). There were no significant differences between the groups regarding the presence of chronic rejection, graft or patient survival. With respect to adverse effects associated with the treatment, there was only a significant difference in the presence of diarrhea in the TAC/MMF group. Conclusion. A significant difference was only found in terms of a higher number of acute rejections in the group treated with TAC/MMF. These findings are in agreement with local experience, in which this scheme can be used in selected patients, with good clinical results and lower costs for the health system. So far, this is the first retrospective study in Colombia and Latin America to make a comparison such as the one presented.

Variantes genéticas de la tiopurina metiltransferasa e incidencia de eventos adversos en pacientes con indicación de azatioprina / Genetic polymorphisms of thiopurine methyltransferase and incidence of adverse events in patients with medical indication of azathioprine

La azatioprina es una tiopurina que presenta rango terapéutico estrecho y marcada toxicidad hematológica y hepática. La tiopurina S-metiltransferasa es una enzima que metaboliza ese grupo de drogas. Mutaciones en el gen que codifica dicha enzima aumentan el riesgo de presentar eventos adversos, por lo que su estudio farmacogenético permite contar con información para el diseño de la estrategia terapéutica. Sin embargo, su utilidad en el medio local no está completamente establecida. Fueron incluidos 45 sujetos (13 hombres) con indicación de azatioprina. Se determinó la presencia de las mutaciones *2, *3A, *3B y *3C de TMPT por PCR-RFLP y se analizó la relación entre el genotipo y la incidencia de eventos adversos relacionados al fármaco. Nueve portaban al menos un alelo no funcional, uno de ellos con genotipo *3A/*3A. Se detectó toxicidad en 3 de los 18 que iniciaron tratamiento con azatioprina: 2 pacientes con genotipo normal presentaron eventos adversos leves, y el único evento adverso de gravedad (aplasia medular) ocurrió en el sujeto con genotipo homocigota mutado. El único que presentó genotipo homocigota mutado desarrolló el más grave de los eventos adversos registrados, a pesar de estar en tratamiento con dosis bajas de azatioprina. Por este motivo, la determinación del genotipo de la tiopurina metiltransferasa pareciera ser de utilidad, pero no reemplaza la necesidad de seguimiento clínico y bioquímico en pacientes en tratamiento con tiopurinas.

Azathioprine is a thiopurine which has a narrow therapeutic index and marked hematological and hepatic toxicity. Thiopurine s-methyltransferase is an enzyme involved in the metabolism of thiopurines. Mutations in the gene that encodes the enzyme may augment the risk of adverse events. For that reason, pharmacogenetic determinations prior to the initiation of therapy can provide useful information for the future therapeutic strategy. Nevertheless, its utility in the local environment is not completely established. Forty-five subjects (13 men) who had been prescribed azathioprine were included. The presence of *2, *3A, *3B and *3C mutations were determined by PCR-RFLP, and the relationship between genotype and incidence of adverse events related to the drug was analyzed. Nine carried at least one non-functional allele, one of them with *3A/*3A genotype. Among the eighteen patients who initiated treatment with azathioprine, toxicity was detected in 3 cases: 2 mild events were observed in patients with normal genotype, and the only serious event (bone marrow suppression) occurred in the individual with homozygous mutant genotype. The only homozygous mutant patient developed the most severe of the registered events, in spite of being under treatment with low doses of azathioprine. This is the reason why enzymatic determination could be of utility, even though it does not replace clinical and biochemical follow-up in patients under thiopurine treatment.

Enfermedad pulmonar intersticial en pacientes con esclerosis sistémica. Revisión narrativa de la literatura / Intersticial pulmonary disease in patients with systemic sclerosis. Narrative review of the literatura / Doença pulmonar intersticial em pacientes com esclerose sistémica. Revisão narrativa da literatura

RESUMEN Introducción: la esclerosis sistémica es una enfermedad autoinmune crónica, caracterizada por la tríada de vasculopatía de pequeños vasos, activación del sistema inmune y aumento de los depósitos de matriz extracelular tanto en la piel como en los órganos internos. En los últimos años, el compromiso pulmonar ha cobrado gran importancia, pasando a ser la primera causa de muerte, dada la disminución de la mortalidad por crisis renales con el advenimiento de los inhibidores de la enzima convertidora de angiotensina. La afección pulmonar puede ocurrir como hipertensión o enfermedad intersticial difusa; esta última es más común en pacientes con la variedad generalizada, en los primeros tres años de la enfermedad. Tiene mal pronóstico si no se inicia el tratamiento, cuya meta es detener el deterioro de la función pulmonar. Entre los tratamientos disponibles, la ciclofosfamida cuenta con la mejor evidencia, pero se están estudiando, con resultados preliminares satisfactorios, otros tratamientos como micofenolato mofetil, rituximab, trasplante autólogo de células hematopoyéticas y trasplante de pulmón. Objetivo: describir, de acuerdo con lo reportado en la literatura, la epidemiología, la fisiopatología, los métodos diagnósticos y el tratamiento de la enfermedad pulmonar intersticial en pacientes con esclerosis sistémica. Métodos: revisión estructurada, no sistemática de la literatura, enfocada en los aspectos de interés, mencionados y que incluyó 52 artículos.

SUMMARY Introduction: Systemic sclerosis is a chronic autoimmune disease, characterized by the triad of small vessel vasculopathy, immune system activation and increased deposits of extracellular matrix in the skin and internal organs. In the last few years, pulmonary involvement has gained relevance since the introduction of angiotensin enzyme converter inhibitors with the subsequent decline in scleroderma renal crisis mortality, transforming scleroderma lung disease in the leading cause of mortality. Pulmonary involvement can manifest as hypertension or interstitial lung disease, which usually occurs in patients with generalized scleroderma in the first three years of the disease. Its prognosis is poor without treatment which is aimed at stopping pulmonary function deterioration. Among treatment options, cyclophosphamide has the best evidence, and mycophenolate mofetil, rituximab, and stem cell and lung transplantation are currently under investigation with positive preliminary results. Objective: To describe, according to reports in the literature, epidemiology, pathophysiology, diagnostic methods, and treatment of interstitial lung disease in systemic sclerosis. Methods: Structured, non-systematic literature review, focused on the aforementioned aspects of interest. It included 52 articles.

RESUMO Introdução: a esclerose sistémica é uma doença autoimune crônica, caracterizada pela tríada de vasculopatia de pequenos vasos, ativação do sistema imune e aumento dos depósitos de matriz extracelular tanto na pele como nos órgãos internos. Nos últimos anos, o compromisso pulmonar há cobrado grande importância, passando a ser a primeira causa de morte, dada a diminuição da mortalidade por crises renais com o advento dos inibidores da enzima convertedora de angiotensina. A afecção pulmonar pode ocorrer como hipertensão ou doença intersticial difusa; esta última é mais comum em pacientes com a variedade generalizada, nos primeiros três anos da doença. Tem mal prognóstico se não se inicia o tratamento, cuja meta é deter o deterioro da função pulmonar. Entre os tratamentos disponíveis, a ciclofosfamida conta com a melhor evidência, mas se está estudando, com resultados preliminares satisfatórios, outros tratamentos como micofenolato mofetil, rituximab, transplante autólogo de células hematopoiéticas e transplante de pulmão. Objetivo: Descrever, de acordo com o reportado na literatura, a epidemiologia, a fisiopatologia, os métodos diagnósticos e o tratamento da doença pulmonar intersticial em pacientes com esclerose sistémica. Métodos: revisão estruturada, não sistemática da literatura, enfocada nos aspectos de interesse, mencionados e que incluiu 52 artigos.

Pseudotumor esclerosante de órbita / Sclerosing orbital pseudotumor

RESUMO O pseudotumor esclerosante de órbita é um subtipo raro de pseudotumor inflamatório idiopático de órbita. É mais comum em adultos e apresenta diagnóstico de exclusão. A primeira linha de tratamento são os esteroides. O subtipo esclerosante apresenta resposta moderada aos esteroides devido à predominância de fibrose e colágeno na histologia. Relatamos o caso de um paciente com diagnóstico histológico de pseudotumor esclerosante de órbita que teve boa resposta ao tratamento com corticoide associado à azatioprina.

ABSTRACT Sclerosing orbital pseudotumor is a rare subtype of idiopathic orbital inflammatory pseudotumor. It's more common in adults and presents diagnosis of exclusion. Steroids represent the first option of treatment. The sclerosing orbital pseudotumor subtype shows moderate response to steroids due to the predominance of fibrosis and collagen in its histology. We report on a case of a patient with histologic diagnosis of sclerosing orbital pseudotumor successfully treated with corticosteroid associated with azathioprine.

Pancitopenia inducida por azatioprina: Casos clínicos / Azathioprine-induced pancytopenia: Case series

La azatioprina es un fármaco inmunosupresor que ha demostrado efectividad en el tratamiento de la enfermedad inflamatoria intestinal. Su metabolito, la 6-mercaptopurina, es metaboliza-do a través de la tiopurina metiltransferasa. Los pacientes con baja actividad enzimática pueden presentar mayores efectos secundarios. El más frecuente es la leucopenia. Más raramente, aparece mielotoxicidad en forma de pancitopenia. La monitori-zación de la actividad de la tiopurina metiltransferasa permite obtener un perfil individualizado de la actividad enzimática, pero no debe reemplazar la monitorización mediante la realización de hemogramas seriados. Ante un paciente con neutropenia grave y fiebre, debe iniciarse un tratamiento antibiótico empírico precoz para evitar infecciones graves y diseminadas. Se presentan dos casos con esta complicación.

Azathioprine is an immunosuppressive drug that has shown effectiveness in inflammatory bowel disease treatment. Its metabolite, 6-mercaptopurine, is metabolized through thiopurine methyltransferase. Patients with low enzyme activity may have more frequent and severe side effects. The most common is leukopenia, and rarely pancytopenia. The thiopurine methyltransferase activity monitoring shows an individualized profile of enzymatic activity but it should not replace monitoring by performing serial blood counts. In patients with fever and severe neutropenia, early empirical antibiotic treatment should be initiated to prevent severe and disseminated infection. Two patients with this condition are reported.

Actualización de hepatitis autoinmune en pediatría: Reporte de un caso clínico y revisión de la literatura / Update on autoimmune hepatitis in pediatrics: Report of a clinical case and review of literature

La hepatitis autoinmune (HAI) es un proceso inflamatorio crónico y progresivo del hígado, de etiología desconocida. Se caracteriza por presentar niveles elevados de aminotransferasas e inmunoglobulina G (IgG), autoanticuerpos séricos y actividad necroinflamatoria en la histología; en ausencia de una patología conocida que pueda afectar al hígado. Predomina en el sexo femenino. Se describen dos tipos de acuerdo a los autoanticuerpos encontrados. El tratamiento se basa en la inmunosupresión, con el objetivo de evitar la progresión a cirrosis y falla hepática. Los pacientes no respondedores, o que debutan con falla hepática aguda pueden requerir de trasplante hepático. El objetivo es realizar una revisión del tema a partir de un caso clínico. Se presenta a una adolescente de 14 años, derivada para estudio por probable patología autoinmune. El diagnóstico inicial fue de probable HAI, que se presentó como una falla hepática grave-fulminante. Posteriormente al descartar otras etiologías (infecciosas y metabólicas), presentar autoanticuerpos antinucleares (ANA) positivos y evidenciar cirrosis en la punción biópsica hepática, se confirmó el diagnóstico de cirrosis autoinmune. Se inició tratamiento con prednisona y azatioprina, con buena respuesta clínica y de laboratorio. El diagnóstico oportuno de HAI y el inicio del tratamiento en forma temprana evitan en la mayoría de los casos la progresión de la enfermedad y el requerimiento de trasplante hepático.

Autoimmune hepatitis is a chronic and progressive inflammatory process of the liver, of unknown etiology. It is characterized by presenting increased levels of aminotransferases and immunoglobulin G (IgG), serum antibodies and histologic necro-inflamatory activity, with unknown pathology that may affect the liver. It is more frequent in women, Two types of autoimmune hepatitis are described, according to the antibodies found. Treatment is based on immunosuppression, with the objective of avoiding progression to cirrhosis and liver failure. Patients who do not respond or who present with severe liver failure may require liver transplant. The objective of the study is to review the topic based on a clinical case. The study presents the case of a 14 year old adolescent who is referred to be examined for possible autoimmune pathology. Initial diagnosis was probable autoimmune hepatitis, which presented with acute liver failure. Subsequently, when other etiologies were discarded (infectious and metabollic), positive antinuclear autoantibodies were present and liver hepatic biopsy evidenced cirrhosis, autoimmune cirrhosis was confirmed. Treatment was initiated with prednisone and azathioprine, being the clinical and lab response good. In most cases, timely diagnosis of autoimmune hepatitis and early initiation of treatment avoid progression of the disease and the need for a liver transplant.

Eficacia clínica de azatioprina (AZA) en el tratamiento de colitis ulcerativa (CU) leve a moderada, con respuesta inadecuada a manejo con esteroides / Clinical Efficacy of Azathioprine (AZA) for Treatment of Mild to Moderate Ulcerative Colitis (UC) in Patients Who Have Responded Inadequately to Steroids

Introducción: los estudios de azatioprina (AZA) en el tratamiento de colitis ulcerativa (CU) son escasos y la mayoría tiene más de una década. Es necesario establecer la eficacia de AZA en nuestro medio, en sujetos con respuesta inadecuada a esteroides. Objetivo: evaluar en nuestra población la respuesta clínica a AZA, tanto a corto como a largo plazo, en CU con respuesta inadecuada a esteroides. Materiales y métodos: se realizó un estudio descriptivo retrospectivo, revisando historias clínicas entre agosto de 2001 y mayo de 2014 de 215 pacientes con CU incluidos en nuestra base de datos del Hospital "Pablo Tobón Uribe", de los cuales 69 (32%) habían recibido AZA. 30 pacientes recibieron al menos 3 meses de tratamiento con AZA en dosis óptima de al menos 2,0 mg/kg, por respuesta inadecuada a esteroides, y fueron incluidos en el estudio. Resultados: el seguimiento promedio de los pacientes fue de 20 meses (3 meses-72 meses). Se encontró remisión clínica en 17 (57%) de 30 pacientes y respuesta parcial en 12 de 30 sujetos (40%) durante 3 meses de tratamiento. Al año, de los 30 pacientes iniciales, 16 (53%) mantenían remisión clínica, 3 (10%) respuesta parcial y 5 (17%) presentaron recaídas y recibieron terapia biológica. 16 pacientes (53%) lograron suspensión de esteroides al año de seguimiento. Ningún paciente requirió colectomía. Conclusiones: este estudio demuestra una tasa de remisión clínica de 53% con AZA en CU leve a moderada al año de seguimiento, logrando suspender esteroides en el 53% de los pacientes. AZA es una opción terapéutica de bajo costo y segura, que puede considerarse en este grupo de pacientes previo al inicio de terapia biológica.

Introduction: Because there are very few studies of the use of azathioprine (AZA) for treatment of ulcerative colitis, and most are more than a decade old, we need to establish the efficacy of AZA in our environment for patients who have responded inadequately to steroids. Objective: The objective of this study is to evaluate short and long term clinical responses to AZA by ulcerative colitis patients in our population who have had inadequate responses to treatment with steroids. Materials and Methods: This is a retrospective study based on a database review of the medical records of 215 ulcerative colitis patients treated at the Hospital Pablo Tobon Uribe between August 2001 and May 2014. Sixty-nine patients (32%) had received AZA, and 30 patients had received at least 3 months of treatment with AZA at the optimal dose of at least 2.0 mg/kg after having responded inadequately to treatment with steroids. This group was included in the study. Results: The median follow-up time was 20 months with a range from three months to 72 months. After three months of treatment, clinical remission was found in 17 patients (57%) out of 30 patients, and partial responses were found in 12 out of 30 subjects (40%). A year after the initial follow-up, 16 patients (53%) maintained clinical remission, three (10%) continued to have partial responses, and five (17%) had relapsed and had received biological therapy. Sixteen patients (53%) achieved one year with steroid treatment suspended and no patients required colectomies. Conclusions: This study demonstrates a clinical remission rate of 53% for patients with mild to moderate ulcerative colitis who were treated with AZA. One year follow-ups showed that continuous suspension of steroid treatment had been achieved in 53% of patients. AZA is an inexpensive and safe therapeutic option which can be considered prior to initiating biological therapy for these patients.

Trasplantes renales en niños y adolescentes en el hospital Dr. Gustavo Fricke de Viña del Mar: recuento histórico y resultados según grupo de edad / History of kidney transplants performed in children and teenagers in Hospital Doctor. Gustavo Fricke, Viña del Mar: a detailed narration of each kidney transplant

Historia de los trasplantes renales efectuados en niños y adolescentes en el Hospital Dr. Gustavo Fricke de Viña del Mar: Una narración pormenorizada de cada trasplante. En este artículo se narra la historia de los trasplantes renales pediátricos efectuados en el hospital Dr. Gustavo Fricke entre 1984 y 2000. Durante el período se efectuaron 19 trasplantes en niños y adolescentes. De ellos, 42 por ciento se efectuó en niños menores de 15 años y 58 por ciento en adolescentes entre 15 y 18 años. El tiempo que permanecieron en diálisis crónica fue de 26 y 13 meses, respectivamente. Los niños recibieron un riñón más frecuentemente desde un donante fallecido (75 por ciento) y los adolescentes de un donante vivo (91 por ciento). El esquema inmunosupresor más utilizado fue la combinación de azatioprina, ciclosporina y corticoides. Los niños presentaron con mayor frecuencia un rechazo agudo y la necesidad de una reintervención quirúrgica en el postoperatorio que los adolescentes. A la fecha de corte de esta historia, transcurridos 30 años del primer trasplante pediátrico, 43 por ciento de los injertos renales efectuados en niños y 36 por ciento en adolescentes está funcionando, con un rango de duración entre 16 y 20 años...

History of kidney transplants performed in children and teenagers in Hospital Dr. Gustavo Fricke, Viña del Mar, Chile: A detailed narration of each kidney transplant This article told the history of pediatric renal transplants performed in Hospital Dr. Gustavo Fricke between 1984 and 2000. During this period 19 kidney transplants were performed in children and adolescents. Of these, 42 percent were performed in children under 15 years (range: 3-14) and 58 percent in adolescents (15-18 years). The time that patients remain in chronicdialysis was 26 months and 13 months, respectively. Children received a kidney more frequently from a deceased donor(75 percent) and adolescents from a living donor (91 percent). The immunosuppressive regimen most often used was the combination of azathioprine, cyclosporine and corticosteroids. Children had more often acute rejection in the postoperative period and the need of a reoperation. After 30 years of the first pediatric transplant, 43 percent of the renal grafts performed in children and 36 percent in adolescents are functioning, with a length between 16 and 20 years...

Pancitopenia associada a tratamento com azatioprina e mesalazina em paciente com colite ulcerativa: relato de caso / Pancytopenia associated with azathioprine and mesalazine treatment in a patient with ulcerative colitis: case report

Contexto: As doenças inflamatórias intestinais têm se tornado cada vez mais prevalentes, o que leva ao uso cada vez maior de medicaçõescomo os imunossupressores tiopurinas (azatioprina e 6-mercaptopurina) e os salicilatos (como a sulfasalazina e a mesalazina). O objetivo desteartigo é destacar aspectos de um efeito colateral potencialmente grave com essas medicações, a mielotoxicidade. Relato do caso: Mulher de39 anos com história de colite ulcerativa em uso de azatioprina e mesalazina procurou o serviço com queixa de cefaleia inespecífica e febre. Hemograma de entrada apresentava pancitopenia (hemoglobina 3,8 g/dL, leucócitos de 1.800/mm3 com 486/mm3 segmentados e plaquetasde 15.000/mm3). A paciente foi admitida com a hipótese de pancitopenia induzida por medicamentos, sendo a azatioprina e mesalazina suspensos. Após 10 dias de suspensão e suporte com antibióticos para neutropenia febril, hemoderivados e filgrastina, os valores das séries sanguíneas começaram a ascender, a paciente recebeu alta no 19o dia, com melhora clínica e hematológica. Conclusão: A azatioprina é classicamente descrita como causadora de mielotoxicidade, enquanto a mesalazina isoladamente raramente é mencionada. A enzima tiopurinametiltransferase (TPMT) é relacionada ao metabolismo da azatioprina, e baixos níveis de sua atividade estão relacionados à maior toxicidade. No contexto brasileiro não foi estudada a relação custo/efetividade da genotipagem de TPMT ou da verificação de sua atividade antes de iniciar o tratamento. É prudente colher hemograma semanalmente nas primeiras oito semanas após o início de tratamento com azatioprina.

Uso de azatioprina en enfermedad de Crohn ¿En qué estamos? / Current state of the use of azathioprine in Crohn’s disease

Crohn´s disease (CD) is an intestinal pathology that may have a torpid and disabling course. One of the purposes of the pharmalogical therapy is to prevent progression of the disease and keep the patient in clinical remission. Thiopurines (azathioprine (AZT)/6-mercaptopurine (6-MP)) correspond to a group of drugs so far recommended in all current consensus for maintaining remission of the disease. Recent publications have questioned its effectiveness as a maintenance treatment. We reviewed the literature to date and the aforementioned publications trying to clarify the current status of the use of AZT/6-MP in CD. We emphasize the importance of thiopurine therapy guided by levels of its metabolites, 6-thioguanines and 6-metilmercaptopurines and usefulness of Allopurinol in selected cases. It is still pending to determine whether thiopurines have the potential to modify the disease at an early stage. Further studies are needed before conclusions can modify our clinical behavior to continue using AZT/6-MP in patients with CD.

La enfermedad de Crohn (EC) es una enfermedad intestinal que puede tener un curso tórpido e invalidan. Uno de los objetivos del tratamiento farmacológico es evitar la progresión de la enfermedad y mantener al paciente en remisión. Las tiopurinas (azatioprina (AZT)/6-mercaptopurina (6-MP) corresponden a un grupo de fármacos hasta ahora recomendados en todos los consensos para mantener la remisión de esta enfermedad. Publicaciones recientes han cuestionado su efectividad como tratamiento de mantención. Revisamos la literatura disponible hasta la fecha y las mencionadas publicaciones, intentando esclarecer el estatus actual del uso de AZT/6-MP en EC. Recalcamos la importancia de realizar la terapia con tiopurinas guiada según los niveles de sus metabolitos 6-tioguaninas y 6-metilmercaptopurinas y la utilidad del uso de alopurinol en casos seleccionados. Conclusión: Está pendiente determinar si las tiopurinas tienen el potencial de modificar la enfermedad tempranamente. Se requieren mayores estudios antes de sacar conclusiones que modifiquen nuestra conducta clínica en lo que respecta a seguir usando AZT/6-MP en pacientes con EC.

Hiperplasia nodular regenerativa del hígado secundaria a uso de azatioprina por trasplante renal previo, tratado con trasplante combinado hepático y renal / Combined hepatic and renal transplant after nodular regenerative hyperplasia of the liver secondary to azathioprine in renal transplant patient

Nodular regenerative hyperplasia is an uncommon condition, characterized by the presence of regenerative nodules with minimal or absence of fibrosis, which can lead to non-cirrhotic portal hypertension. There are numerous diseases, conditions and drugs that can cause it. Thiopurines, a group of immunosuppressors used in transplanted patients, has been linked to this entity. We report a case of a renal transplant woman, who has been on chronic therapy with azathioprine and that develops portal hypertension and end-stage renal disease, undergoing combined hepatic and renal transplant. Histological examination of the explanted liver was compatible with nodular regenerative hyperplasia. How azathioprine causes this entity is unknown, but endothelial vascular damage in a dose-dependent manner is postulated as the main mechanism. To our knowledge, this is the first case report of a renal transplant patient who develops nodular regenerative hyperplasia of the liver in association with azathioprine, and undergoes combined hepatic and renal transplant, with a favorable outcome 5 years post procedure.

La hiperplasia nodular regenerativa es una entidad infrecuente, que se caracteriza por la presencia de nódulos hepáticos con ausencia o mínima fibrosis y que puede llevar a hipertensión portal de origen no cirrótico. Existen diversas enfermedades, condiciones y medicamentos que la causan, destacando entre estos últimos las tiopurinas, inmunosupresores utilizados habitualmente en trasplantados. Se presenta el caso de una paciente trasplantada renal usuaria crónica de azatioprina, que desarrolla hipertensión portal además de deterioro de la función renal, requiriendo de un doble trasplante hepático y renal, destacando en la biopsia del explante hallazgos histológicos compatibles con hiperplasia nodular regenerativa. Los mecanismos de daño por azatioprina en esta entidad son desconocidos, pero se postula al daño endotelial dosis-dependiente como principal causa. La revisión de la literatura demuestra que este caso corresponde al primero de hiperplasia nodular regenerativa secundaria a azatioprina en trasplantado renal, que requiere de doble trasplante hepático y renal con evolución favorable hasta 5 años post trasplante.

Toxicity of azathioprine: why and when? analysis of the prevalence of polymorphism in Joinville, SC, Brazil / Toxicidade da azatioprina: por que e quando? análise da prevalência de polimorfismo em Joinville, SC

CONTEXT: The use of thiopurine drugs such as azathioprine and 6-mercaptopurine has become quite common in the treatment of inflammatory bowel disease, transplantation and acute leukemias. Despite their effectiveness, these drugs are capable of causing drug-induced toxicity with the risk of death by myelosuppression. It is now known that these complications occur because of genetic polymorphisms of the thiopurinemethyltransferase (TPMT) enzyme, responsible for its metabolism. OBJECTIVE: To assess the prevalence of thiopurine methyltransferase polymorphisms in the population of Joinville, SC, Brazil. METHODS: We analyzed the frequency of four main allelic variants of the TPMT gene in 199 blood donors from Joinville, from February to April 2010. RESULTS: The normal allele ("wild-type") was found in 93.9% of subjects studied. TPMT variants were detected in 12 subjects (6.03%). CONCLUSIONS: From this study, it was estimated at 6% the risk of toxicity by the administration of azathioprine and 6-mercaptopurine to patients in Joinville.

CONTEXTO: A utilização de drogas tiopurinas como a azatioprina e a 6-mercaptopurina tem se tornado bastante frequente no tratamento de doenças inflamatórias intestinais, transplantes e leucemias agudas. Apesar de sua efetividade, estas drogas são capazes de causar toxicidade droga-induzida com risco de morte através de mielossupressão. Sabe-se hoje que estas complicações ocorrem em decorrência de polimorfismos genéticos da enzima tiopurina metiltransferase (TPMT), responsável por sua metabolização. OBJETIVOS: Avaliar a prevalência do polimorfismo do gene da TPMT na população de Joinville, SC. MÉTODOS: Foi analisada a frequência das quatro principais variantes alélicas do gene da TPMT em 199 doadores de sangue da cidade de Joinville, SC, no período de fevereiro a abril de 2010. RESULTADOS: O alelo normal ("selvagem") foi encontrado em 93,9% dos indivíduos estudados. Variantes da TPMT foram detectadas em 12 sujeitos (6,03%). CONCLUSÕES: A partir do presente estudo, pode-se estimar em cerca de 6% o risco de toxicidade na administração de azatioprina e 6-mercaptopurina a pacientes em Joinville.