Role of therapeutic plasma exchange as a desensitization therapy in human leukocyte antigen incompatible renal transplant patients: A single-center experience

Abstract Objective Despite an increase in the rate of successful live donor renal transplantation done annually, the number of potential recipients with acceptable donors is relegated to the ever-expanding cadaver-donor waiting list due to sensitization to human leukocyte antigen (HLA) antibodies. If not sufficiently suppressed, these preformed HLA antibodies can trigger antimicrobial resistance (AMR) and early graft loss. To ameliorate this situation, various desensitization treatments are administered to provide a survival benefit to highly sensitized patients. Method One hundred and six patients in the time frame of January 2017 to March 2019 were included in the study group. The desensitization protocol included therapeutic plasma exchange and administration of low-dose intravenous immunoglobulin (100 mg/kg per therapeutic plasma exchange (TPE) session) to highly sensitized patients (treatment group) who subsequently underwent renal transplantation after negative pre-transplant Centers for Disease Control and Prevention Luminex crossmatch (CDC/LumXM). We compared graft survival rates between the group undergoing desensitization (treatment group) and matched control group of patients that underwent HLA-compatible transplantation. Results In the treatment group, Kaplan-Meier analysis estimates an average rate of patient graft survival of 95.2% at 3 years post-transplant, as compared with the rate of 86.9% in the same time frame for the control-matched group (p < 0.05 for both comparisons). Conclusion Desensitization treatment with TPE before live donor renal transplantation in the case of patients with HLA sensitization provides better survival benefits along with monitoring for donor-specific antibodies (DSAs) and other infections, rather than waiting for a compatible organ donor. The data lays out evidence that desensitization treatments can assist overcome HLA incompatibility barriers in live donor renal transplantation.

Aspectos técnicos y clínicos de la prueba cruzada de histocompatibilidad en el trasplante de órganos solidos / Technical and clinical aspects of the histocompatibility crossmatch assay in solid organ transplantation

La presencia de anticuerpos dirigidos contra los antígenos leucocitarios humanos (Human Leukocyte Antigens, HLA) que se expresan en las células del donante, es uno de los factores de riesgo más importantes asociados con las complicaciones clínicas después del trasplante. La prueba cruzada es una de las pruebas de histocompatibilidad más eficaces para la detección de anticuerpos específicos contra el donante en los receptores de injertos. En los primeros métodos de la prueba cruzada, se utilizaba la citotoxicidad dependiente del complemento, que es útil para detectar dichos anticuerpos responsables del rechazo hiperagudo del injerto, pero carece de la sensibilidad adecuada. Por ello, se desarrollaron métodos de pruebas cruzadas más sensibles, entre ellas, la prueba cruzada por citometría de flujo que hoy se considera el método preferido. En este artículo se revisa la evolución de la prueba cruzada y los factores más importantes que deben tenerse en cuenta al realizarla y al interpretar los resultados de esta prueba fundamental para la supervivencia a largo plazo del injerto.

The presence of antibodies directed against human leukocyte antigens (HLA) expressed on donor cells is a significant risk factor for serious clinical complications after transplantation. The crossmatch assay is one of the most important tests available for the detection of donor-specific antibodies in potential allograft recipients. Early crossmatch methods utilized complement-dependent cytotoxicity, which is useful for detecting the donor-specific anti- HLA antibodies responsible for hyperacute allograft rejection but lacks adequate sensitivity. Consequently, more sensitive crossmatch methods have been developed, ultimately leading to the flow cytometry crossmatch as the currently preferred methodology. Herein, we review the evolution of the crossmatch assay and the most important factors to consider when performing and interpreting the results of this fundamental assay for ensuring the long-term survival of the transplanted organ.

Neutropenia aloimune neonatal em gêmeas idênticas / Neonatal alloimmune neutropenia in identical twins

A neutropenia aloimune neonatal (NAN) é uma patologia causada pelo antagonismo imunológico, como a doença hemolítica do recém-nascido ou a trombocitopenia aloimune neonatal, mas relacionada aos neutrófilos, em vez de glóbulos vermelhos ou plaquetas. Descreveremos um caso clínico de duas gêmeas idênticas nascidas a termo, com Apgar de 8 e 9, sendo que após algumas horas do nascimento apresentaram febre. Um exame de sangue revelou neutropenia grave que resultou em sepse. O diagnóstico da NAN foi realizado clinicamente e por testes de histocompatibilidade. A prova cruzada por citometria de fluxo foi positiva, usando soro da mãe e suspensões celulares (granulócitos e linfócitos) das gêmeas e do pai. Este teste não fornece informações sobre para qual sistema genético os anticorpos foram positivos, se contra os antígenos específicos de neutrófilos humanos (HNA) ou contra os antígenos leucocitários humanos (HLA). Para o esclarecimento, realizamos o teste de aglutinação de granulócitos (GAT) com um painel de doadores fidelizados e com antígenos HNA1-5 conhecidos, utilizando o soro materno como reagente. Foi também realizada a pesquisa de anticorpos anti-HLA e anti-HNA no soro materno. Os genótipos HLA e HNA foram identificados, permitindo conhecer as especificidades dos anticorpos maternos contra os antígenos dos neutrófilos do marido e das filhas. O diagnóstico de NAN não é realizado na maioria dos hospitais de nosso país e do exterior, devido à dificuldade de execução dos testes de histocompatibilidade, no entanto a prova cruzada por citometria de fluxo pode facilmente ser implantada nos laboratórios clínicos, sendo que está descrita detalhadamente nesse caso clínico.

Neonatal alloimmune neutropenia (NAN) is a disease caused by immunological antagonism, such as hemolytic disease of the newborn or neonatal alloimmune thrombocytopenia, but related to neutrophils rather than to red blood cells or platelets. We will describe a clinical case of two identical twins born with Apgar 8 and 9 that started with fever few hours after delivery. A blood test revealed severe neutropenia, which was followed by sepsis. The diagnosis of NAN was done clinically and by histocompatibility testing. Flow cytometry crossmatch was positive, using mother serum and cell suspensions (granulocytes and lymphocytes) from the twin girls and from the father. This test did not provide information about the genetic system for which the antibodies are positive, if against human neutrophil antigens (HNA) or human leucocyte antigens (HLA). To clear this, the granulocyte agglutination test (GAT) was performed with a panel of control donors with known HNA1-5 antigens, using the maternal serum as a reagent. We did also a Luminex screening assay for detection of anti-HLA and anti-HNA antibodies in the mother serum. The HLA and HNA genotypes were identified, which allowed to define specificities in mother's antibodies against the neutrophil surface antigens from her husband and from the twins. The diagnosis of NAN diagnose is not done in most hospitals worldwide, mainly by the difficulty in executing the histocompatibility test. However, the crossmatch by flow cytometry could be easily done in clinical laboratories following the method described in this article.

Tumor venéreo transmissível canino com resistência quimioterápica e metástase esplênica. Relato de caso / Canine transmissible venereal tumor with chemotherapy resistance and splenic metastasis. Case report

RESUMO O Tumor Venéreo Transmissível Canino (TVTC) é uma neoplasia de células redondas que tem a particularidade de se implantar em mucosas que tenham perdido a sua integridade. Nesse local o tumor prolifera e ocasionalmente origina metástase. Em geral, o tumor responde ao tratamento com sulfato de vincristina, porém a resistência quimioterápica associada ao fenótipo tumoral tem sido documentada. Objetivou-se relatar um caso de TVTC genital de fenótipo citológico misto com metástase esplênica e o insucesso da quimioterapia com sulfato de vincristina, em uma fêmea canina, da raça Australian Cattle Dog, de cinco anos de idade. Após diagnóstico citológico e histológico, o tumor primário foi ainda caracterizado em fase de progressão e mostrou baixa expressão de moléculas do complexo principal de histocompatibilidade (MHC) (4,4 ± 2% classe I e 11 ± 4,1% classe II). A cadela foi submetida à ovariohisterectomia e esplenectomia terapêutica e não apresentou recidiva do tumor após 12 meses de acompanhamento clínico.

ABSTRACT The canine transmissible venereal tumor is a type of round cell cancer that have the particularity of implanting in mucous tissue, when they lose their integrity, at which point the tumour proliferates and may even develop metastases. The tumor typically responds well to vincristine sulfate chemotherapy, although there are cases of resistance to the drug correlated with the tumoral phenotype. We describe herein a genital mixed TVTC case with metastases at spleen and failure at vincristine sulfate chemotherapeutic treatment in a five years old Australian Cattle Dog female. After the cytological, histological and cytogenetic diagnostic, the primary tumor was still characterized in progression phase and showed low major histocompatibility complex expression MHC (4,4 ± 2% class I e 11 ± 4,1% class II. The dog underwent therapeutic splenectomy and ovariohysterectomy and did not present tumor recurrence within 12 months of clinical follow-up.

Afectación cardiopulmonar por citomegalovirus en individuos inmunocompetentes / Cardiopulmonary involvement due to cytomegalovirus in immunocompetent individuals

Resumen La infección por Citomegalovirus en adultos sanos suele cursar de forma asintomática o como un cuadro de mononucleosis. La afectación cardiopulmonar en individuos inmunocompetentes es infrecuente y se asocia a mal pronóstico. Su diagnóstico exige una elevada sospecha clínica. Se presenta el caso clínico de un paciente joven que debutó con clínica de neumonía atípica y en el estudio posterior se descubrió miocardiopatía dilatada con disminución de la contractilidad miocárdica. La serología para citomegalovirus fue positiva y el paciente recibió terapia antiviral específica con excelente resultado.

Abstract Cytomegalovirus infection in healthy adults is usually asymptomatic or as signs and symptoms of a mononucleosis. Cardiopulmonary involvement in immunocompetent individuals is uncommon and is associated with a poor prognosis. Its diagnosis requires a high clinical suspicion. The case is presented of a young patient in whom the first clinical sign was an atypical pneumonia, and in the subsequent study a dilated cardiomyopathy with a decrease in myocardial contractility was discovered. The serology for cytomegalovirus was positive, and the patient received specific antiviral therapy, with an excellent outcome.

Activación de la célula T, alteraciones en el lupus eritematoso sistémico, una revisión narrativa / T-cell activation, alterations in systemic lupus erythematosus: A narrative review

Resumen La activación de los linfocitos T se inicia a través de la presentación de antígenos endógenos o exógenos por células presentadoras de antígenos a través del complejo mayor de histocompatibilidad, el cual se une a un receptor especializado presente en los linfocitos T. Este reconocimiento desencadena una cascada de señalización intracelular que conlleva a un aumento en la expresión de integrinas, modificaciones del citoesqueleto y producción de factores de transcripción involucrados en la liberación de citocinas y mediadores inflamatorios. Uno de los inductores más importantes en la activación celular es el complejo enzimático con acción tirosina cinasa. Las cinasas que pertenecen a la familia SRC (SFK), FYN y LCK están involucradas en un gran número de procesos importantes en la activación, modulación de la respuesta linfocitaria y el desarrollo de enfermedades autoinmunes. La regulación de la señalización de las cinasas, así como de proteínas adaptadoras involucradas en la activación del linfocito T, son fundamentales para mantener el umbral de activación y modulación de la respuesta del linfocito. La fosforilación de sitios de regulación positiva de estas proteínas es importante para permitir una configuración activa de la proteína y de esta forma su máxima capacidad como cinasa. La fosforilación de los sitios de regulación negativa conlleva a una configuración cerrada de la proteína de tal forma que reduce su función de cinasa e inhibe su función. Las alteraciones en la señalización por modificación de algunas proteínas citoplasmáticas se asocian en algunos casos al desarrollo de enfermedades autoinmunes, como el lupus eritematoso sistémico. En condiciones fisiológicas, el complejo receptor de linfocitos T se reagrupa con complejos proteicos que interactúan armónicamente para generar una sen al interna. Los eventos de señalización alterados son en parte los responsables de una expresión anómala de citocinas, entre ellas la interleucina-6 (IL-6), IL-10, IL-2, IFN y CD40 ligando; estas modificaciones alteran la capacidad de los linfocitos T para sobre estimular a los linfocitos B, traduciéndose en un aumento en la producción de autoanticuerpos y en el desencadenamiento de la enfermedad autoinmune.

Abstract The activation of T cells is initiated by the presentation of exogenous or endogenous antigens, by antigen presenting cells through the major histocompatibility complex, which binds to a special receptor on T cells. This acknowledgement triggers a cascade of intracellular signalling that leads to an increase in integrin expression, cytoskeletal modifications, and transcription factors production involved in the liberation of cytokines and inflammatory mediators. One of the most important inducers in cell activation is the enzymatic complex with tyrosine kinase action. The kinases which belong to the SRC (SFK) LCK and FYN family have been involved in a large number of important processes in the activation and modulation of the T cells response, as well as in the development of autoimmune diseases. Regulating the kinases signalling, as well as the adapter proteins involved in T cell activation, is essential for maintaining an activation threshold, as well as the modulation of cell response. The phosphorylation of the positive regulation sites of these proteins is important to allow an active configuration of the protein and thereby its maximum capacity as kinase. The phosphorylation of negative regulation sites leads to a closed configuration of the protein that reduces its kinase function, and thereby inhibits its own function. The alteration in signalling by the modification of certain cytoplasmic proteins in some cases is associated with the development of autoimmune diseases, such as systemic lupus erythematosus. Under physiological conditions the T cell receptor complex regroups with protein complexes that interact harmonically to generate an internal signal. The altered signalling events are partly responsible for an anomalous expression of cytokines, including the interleukin-6 (IL-6), IL-10, IL-2, IFN, and CD40 linking, these modifications affects the cells ability to over-stimulate T and B cells, resulting in an increased production of autoantibodies and the triggering of the autoimmune disease.

UV induced surface modification on improving the cytocompatibility of metallocene polyethylene

ABSTRACT Demand for medical implants is rising day by day as the world becomes the place for more diseased and older people. Accordingly, in this research, metallocene polyethylene (mPE), a commonly used polymer was treated with UV rays for improving its biocompatibility. Scanning electron microscopy (SEM) images confirmed the formation of crests and troughs, which depicts the improvement of surface roughness of mPE substrates caused by UV etching. Accordingly, the contact angle measurements revealed that the wettability of mPE-2.5 J/cm2 (68.09º) and mPE-5 J/cm2 (57.93º) samples were found to be increased compared to untreated mPE (86.84º) indicating better hydrophilicity. Further, the UV treated surface exhibited enhanced blood compatibility as determined in APTT (untreated mPE- 55.3 ± 2.5 s, mPE-2.5 J/cm2 - 76.7 ± 4.1 s and mPE-5 J/cm2 - 112.3 ± 2 s) and PT (untreated mPE - 24.7 ± 1.5 s, mPE- 2.5 J/cm2 - 34.3 ± 1.1 s and mPE-5 J/cm2 - 43 ± 2 s) assay. Moreover, the treated mPE-2.5 J/cm2 (4.88%) and mPE-5 J/cm2 (1.79%) showed decreased hemolytic percentage compared to untreated mPE (15.40%) indicating better safety to red blood cells. Interestingly, the changes in physicochemical properties of mPE are directly proportional to the dosage of the UV rays. UV modified mPE surfaces were found to be more compatible as identified through MTT assay, photomicrograph and SEM images of the seeded 3T3 cell population. Hence UV-modified surface of mPE may be successfully exploited for medical implants.

Morfometria do osso esterno e sua correlação com o volume pulmonar / Sternum bone morphology and its correlation with lung volume

Este estudo teve por objetivo desenvolver um modelo matemático que a partir da extensão do osso esterno fornecesse o tamanho do pulmão compatível para o receptor. Foram coletadas as medidas antropométricas do tórax de 250 indivíduos, através de exame de tomografia computadorizada. Os resultados apontam que a medida do osso esterno (distância da incisura jugular até processo xifóide) apresenta correlação positiva com todas as outras medidas do tórax (medida ântero-posterior e látero-medial entre II e III costela, e ápice à base de ambos os pulmões). Entretanto, o volume pulmonar e sua relação com o osso esterno apresentam discrepâncias quando analisados sob a correlação de Pearson, pois a relação entre a medida da incisura jugular ao processo xifóide e a medida do ápice à base do pulmão direito e esquerdo, apresenta correlação positiva média (0,31-0,6). Já a medida da incisura jugular ao processo xifóide com a medida ântero-posterior e látero-medial do tórax, apresenta correlação significativa baixa (0-0,3). Então, a análise estatística da correlação de Pearson demonstrou ser inviável o desenvolvimento da fórmula, pois esta não seria confiável já que funcionaria para cerca de apenas 39% dos pacientes. Assim, o melhor método para determinar o doador para o transplante, continua sendo a análise de fatores de risco, a capacidade vital forçada do doador e receptor com estatura maior do que a do doador.

This study aimed at developing a mathematical model that can provide the compatible lung size for the recipient from the length of the sternum bone. Anthropometric chest measurements of 250 individuals were collected through a CT scan. The results indicate that the measurement of the sternum bone (distance from the jugular notch to the xiphoid process) shows a positive correlation with all other thorax measurements (antero-posterior and medial-posterior measurement between ribs II and III, and apex-to-base on both lungs). However, lung volume and its correlation to the sternal bone present discrepancies when analyzed under Pearson's correlation, since the relation between the jugular notch measurement and the apex measurement at the base of the right and left lungs shows a positive correlation mean (0.31-0.6). The measurement of the jugular notch in the xiphoid process with the anterior-posterior and medial-medial measurements, presents a low significant correlation (0-0.3). Therefore, the statistical analysis of the Pearson's correlation showed that the formula could not be applied since it would not be reliable since it would work for only 39% of the patients. Thus, the best method to determine the donor for transplantation remains the analysis of risk factors, the forced vital capacity of the donor, and the recipient being taller than the donor.

Human leukocyte antigen allele linkage disequilibrium and haplotype structure in volunteer bone marrow donors of Paraná State

Abstract Background Bone marrow transplantation has been used in the treatment of various diseases, especially hematologic diseases. The success of this treatment, among other factors, requires human leukocyte antigens (HLA) compatibility between patient and donor. Knowing the human leukocyte antigens allele group and haplotype frequencies as well as the linkage disequilibrium between alleles of different human leukocyte antigens loci can shorten the search time for a compatible bone marrow donor. Objective To assemble and analyze data on human leukocyte antigens frequencies available in the Laboratory of Immunogenetics and Histocompatibility (LIGH) database of the Universidade Federal do Paraná adding an estimation of the Hardy-Weinberg equilibrium and linkage disequilibrium. Methods The sample was composed of seven populations grouped by self-declared ancestry or inferred from the surname as follows: Laboratory of Immunogenetics and Histocompatibility database (all groups), descendants of Italians, Poles, and Asians, Afro-Brazilians, Mulattos (mixed ancestry) and Amerindians. Human leukocyte antigens genotyping was carried out using the polymerase chain reaction-sequence specific primers (PCR-SSP) and -sequence specific oligonucleotide (PCR-SSO) technologies. Results There were high frequencies of the HLA-A*02, HLA-B*35 and HLA-DRB1*13 allelic groups in all groups. The same was observed for the HLA-A*01-B*08-DRB1*03 haplotype except for Asian descendants. It was observed that the human leukocyte antigens Laboratory of Immunogenetics and Histocompatibility database and the Asian group are not in Hardy-Weinberg equilibrium. The Italian, Polish, Asian, Mulatto and Amerindian descendants showed haplotypes in complete linkage disequilibrium. Our results were compared with data on the human leukocyte antigens in the Paraná population available from the Brazilian Voluntary Bone Marrow Donor Registry (REDOME) and data published on the population of Curitiba and the northern region of Paraná. Conclusions Haplotypes frequent in the Asian group were not the most frequently observed in the Laboratory of Immunogenetics and Histocompatibility database and the National Bone Marrow Donor Registry for the state of Paraná. Linkage disequilibrium information may prove useful in the search for bone marrow donors for patients awaiting a suitable donor.

Histoplasmosis aguda diseminada en un niño inmunocompetente / Acute disseminated histoplasmosis in an immunocompetent child

La histoplasmosis es una patología endémica en Colombia. La verdadera incidencia en nuestro país es desconocida. En niños inmunocompetentes generalmente es un proceso autolimitado. Algunos casos pueden resultar un dilema diagnóstico por su amplio espectro de manifestaciones clínicas y diagnósticos diferenciales o por las dificultades de su confirmación sobre todo en zonas endémicas. Describimos el caso de un niño inmunocompetente con histoplasmosis diseminada aguda e importante compromiso respiratorio resaltando los dilemas que podrían presentarse en su diagnóstico y manejo.

Histoplasmosis is an endemic pathology in Colombia but its real incidence in the country is unknown. In non-immunocompromised children, the mycosis is mainly a self-limited process. In endemic zones certain cases may represent a diagnostic dilemma due to the broad spectrum of clinical manifestations that complicate differential diagnosis and hinder the proper diagnosis. We describe the case of an immunocompetent child diagnosed with acute disseminated histoplasmosis who exhibited extensive respiratory involvement highlighting the dilemmas faced when attempting to establish the diagnosis and defining management.

Anticuerpos anticitomegalovirus y antivirus de Epstein Barr en pacientes cubanos en espera de trasplante hematopoyético / Anti-citomegalovirus and anti-Epstein Barr virus seroprevalence in cuban patients waiting for hematopoietic stem cell transplant

Las complicaciones secundarias a las infecciones por citomegalovirus (CMV) y virus de Epstein Barr (EBV) constituyen las principales causas de morbilidad y mortalidad por infecciones en los pacientes que reciben injertos de células progenitoras hematopoyéticas (CPH). La detección de anticuerpos específicos contra cada uno de estos virus en el periodo pretrasplante permite prevenir la primoinfección durante la inmunosupresión terapéutica.La investigación tuvo como objetivo determinar la seroprevalencia de anticuerpos anti-CMV y anti-EBV e identificar aquellos pacientes con riesgo de adquirir una infección primaria postrasplante.Se realizó la detección de anticuerpos IgM e IgG anti-CMV y anti-EBV por ELISA, a 110 pacientescon indicación de pruebas de histocompatibilidad para trasplante de CPH, entre enero del 2013 y enero del 2016, en el Departamento de Histocompatibilidad del Instituto de Hematología e Inmunología de La Habana.La seroprevalencia de anticuerpos anti-CMV en la población estudiada fue del 84,5 por ciento y anti-EBV, del 90,9 por ciento. Los menores de 9 años presentaron un porcentaje de positividad del 70,6 y 64,7 por ciento para IgG anti-CMV y EBV respectivamente, encontrándose un incremento de la seroprevalencia con la edad.La seroprevalenciade anticuerpos anti-CMV y anti-EBV en los pacientes en espera de trasplante de CPH en Cuba es semejante a otras poblaciones; lo que sugiere la necesidad evitar el contagio por transmisión a los casos seronegativos(AU)

Secondary complications due to infections caused by Cytomegalovirus (CMV) and Epstein Barr virus (EBV) are the major infectious causes of morbidity and mortality in recipients of hematopoietic stem cell (HSC) grafts. Detection of specific antibodies against each of those viruses in the pre-transplant period allows the prevention of the primary infection during the immune suppressive therapy.The aim of the investigation was to determine seroprevalence of antibodies against CMV and EBV and also to identify the patients in risk of a primary infection in the post-transplant period.The investigation was conducted between January 2013 and January 2016 by the Histocompatibility Department of Instiute of Hematology and Immunology. Antibodies IgM and IgG against CMV and EBV were tested by ELISA in 110 patients with the indication for histocompatibility testing for a HSC graft.Seroprevalence of antibodies against CMV in this population was 84.5 percent. and seroprevalence of antibodies against EBV was 90.9 percent. The 70.6 percent.of children less than 9 years old had positive IgG CMV antibodies and the 64.7 percent. of them had positive IgG EBV antibodies. An increase of seroprevalence with age was found. The seroprevalence of antibodies against CMV and EBV in patients waiting for a HSC transplant in Cuba is similar to the populations in other countries. This result suggests the need of avoiding the transmissiontoseronegative recipients(AU)

Haploidentical transplantation of hematopoietic stem cells / Transplantes haploidênticos de células-tronco hematopoieticas

SUMMARY Objective: To review and discuss the literature on hematopoietic stem cell transplantation (HSCT) with haploidentical donors in Brazil. Method: Literature review. Results: The haploidentical hematopoietic stem cell transplantations have become a safe option in hematology since the 80s, with the possibility of ex-vivo T-cell depletion. However, its broad use worldwide occurred with the advent of haploidentical nonmyeloablative transplants using in vivo T-cell depletion with the administration of post-transplant cyclophosphamide. The results were encouraging, despite the increased risk of infection and post-transplantation recurrence. Recent publications on acute myeloid leukemia, myelodysplastic syndrome and Hodgkin’s lymphoma have shown similar results among haploidentical, unrelated and related full-match transplants. Obviously, these findings of retrospective studies should be confirmed by clinical trials. Conclusions: Transplantation with haploidentical donor has shown to be feasible in Brazil and the first publications and results are showing encouraging results.

RESUMO Objetivo: Revisar e discutir a literatura sobre transplantes de células-tronco hematopoiéticas (TCTH) com doador haploidêntico no Brasil. Métodos: Revisão da literatura médica. Resultados: Os transplantes haploidênticos de células-tronco hematopoiéticas tornaram-se uma opção segura na hematologia a partir dos anos 1980, com a possibilidade de depleção de células T ex-vivo. No entanto, sua ampla utilização em todo mundo ocorreu após os trabalhos com os transplantes haploidênticos não mieloablativos, com depleção de células T in-vivo, utilizando ciclofosfamida pós-transplante. Os resultados se mostraram encorajadores, apesar do maior risco de infecções e recidiva pós-transplante. Estudos em determinadas patologias, principalmente na leucemia mieloide aguda, mielodisplasia e linfoma de Hodgkin, mostram resultados semelhantes entre transplantes haploidênticos e não aparentados e aparentados totalmente compatíveis. Logicamente, esses achados de estudos retrospectivos precisam ser confirmados por estudos clínicos. Conclusões: No Brasil, a modalidade de transplante com doador haploidêntico se mostrou factível e as primeiras publicações e resultados mostram resultados animadores.

Trasplante renal y donación: análisis crítico / Renal transplantation and donation: a critical analysis

En los últimos veinte años se ha logrado un gran avance en el entendimiento de los mecanismos fisiopatológicos del rechazo del trasplante, lo cual ha mejorado los protocolos de selección de donantes y receptores, la evaluación de los riesgos postrasplante, el diagnóstico y la inmunosupresión para la prevención y el tratamiento del rechazo gracias a nuevos medicamentos más potentes y selectivos. Todo esto ha mejorado, sustancialmente, el pronóstico y la sobrevida a corto y mediano plazo (1-2 años), pero no en el largo plazo. Aunque más del 90 % de los receptores conservan el trasplante renal funcionando al año postrasplante, la tasa anual de falla o pérdida del injerto se ha mantenido relativamente constante. La pérdida tardía del trasplante refleja el impacto de mecanismos tanto inmunológicos como no inmunológicos. Sin embargo, en una serie de la Clínica Mayo, El-Zoghby et al. encontraron que la mayoría de las muertes con pérdida del trasplante se podían atribuir a mecanismos aloinmunes y solo una minoría correspondían a causas no inmunológicas como la nefrotoxicidad por Inhibidores de Calcineurina. Los mecanismos inmunológicos, tanto celulares como mediados por anticuerpos, siguen siendo la mayor amenaza del órgano trasplantado.

In the last twenty years, great progress has been made in the understanding of the pathophysiological mechanisms of transplant rejection, which has improved donor and recipient selection protocols, post-transplant risk assessment, diagnosis and immunosuppression for the prevention and treatment of rejection thanks to new, more potent and selective drugs. All this has substantially improved prognosis and survival in the short and medium term (1-2 years), but not in the long term. Although more than 90% of recipients retain a functioning kidney transplant at one year post-transplantation, the annual rate of graft failure or loss has remained relatively constant. Late transplant loss reflects the impact of both immunologic and nonimmunologic mechanisms. However, in a series from the Mayo Clinic, El-Zoghby et al. found that the majority of deaths with transplant loss were attributable to alloimmune mechanisms and only a minority were due to non-immunologic causes such as calcineurin inhibitor nephrotoxicity. Immunological mechanisms, both cellular and antibody-mediated, remain the major threat to the transplanted organ.

Monitoreo de anticuerpos anti-HLA en pacientes con insuficiencia renal crónica en lista de espera para trasplante / Anti-hla antibodies monitoring in patients with chronic re- nal failure on waiting list for renal transplant in Paraguay

INTRODUCCIÓN: El estudio de anticuerpos anti-HLA en el suero del paciente en lista de espera para trasplante renal es fundamental para optimizar la elección de un donante así como el esquema de inmunosupresión de inducción y mantenimiento acorde al riesgo inmunológico. Estos anticuerpos pueden Encontrarse de manera preexistente al trasplante como resultado de exposición del individuo a transfusiones sanguíneas, embarazos y trasplantes previos. El objetivo del estudio fue determinar la incidencia de inmunización frente a antígenos de HLA, los factores asociados y su impacto en pacientes en espera de un trasplante renal. MATERIAL Y MÉTODOS: En este estudio, observacional retrospectivo de corte trasversal, fueron incluidos 254 pacientes en lista de espera para trasplante renal que acudieron al Laboratorio Central de Salud Pública en el período comprendido entre julio de 2013 y julio de 2015. RESULTADOS: De los 254 pacientes estudiados, 30% presentaron anticuerpos anti-HLA. El evento sensibilizante más significativo fue la exposición a un trasplante previo, presentando anticuerpos anti-HLA el 84% de los candidatos a retrasplante (p<0,05). En segundo lugar se encontraron las mujeres multíparas, presentando un PRA (Panel Reactivo de Anticuerpos) positivo el 69% de ellas (p<0,05). Por último, el 24% de los pacientes poli-transfundidos presentaron anticuerpos anti HLA (p<0,05). CONCLUSIONES: En el trascurso de los dos años de estudio, 51 pacientes fueron trasplantados, de los cuales un solo paciente presentaba anticuerpos anti-HLA antes del trasplante. Esto indica claramente que la inmunización frente a antígenos de HLA representa una barrera para el acceso al trasplante

INTRODUCTION: Anti-HLA antibodies determination in the serum of patients on a waiting list for renal transplant is essential to optimize donor selection as well as for the induction and maintenance immunosuppression scheme, according to immunological risk. These antibodies could be present before transplantation as a result of being exposed to blood transfusions, pregnancies and previous transplants. The objective of the study was to determine immunization against HLA antigens, associated factors and their impact on the waiting list for a renal transplant. METHODS: In this observational retrospective cross sectional study, 254 patients on the waiting list for renal transplant were included. These patients attended the Public Health central laboratory between July 2013 and July 2015. RESULTS: 30% of the 254 studied patients presented anti-HLA antibodies. The most significant sensitizing event was the exposure to a previous transplant (p=<0.05). Multiparous women were in second place, 69% of them presenting positive PRA (panel reactive antibodies) (p=<0.05). Finally 24% of poly transfused patients presented anti-HLA antibodies (p=<0.05). CONCLUSIONS: During the 2 year of the study, 51 patients were transplanted, presenting only one of them anti-HLA antibodies before transplantation. This results clearly indicate that the immunization against HLA represents a barrier for transplantation access

Associações dos anticorpos anti-HLA pré-formados e da compatibilidade HLA à rejeição celular aguda precoce no transplante hepático / Associations of preformed anti-HLA antibodies and HLA compatibility with early acute cellular rejection in liver transplantation

As moléculas HLA são os principais alvos da rejeição nos transplantes de órgãos sólidos. A influência dos anticorpos anti-HLA pré-formados e da compatibilidade HLA no transplante de fígado ainda não está bem definida. A maioria dos transplantes é realizada sem a pesquisa de anticorpos anti-HLA pré-formados e sem pareamento HLA. OBJETIVOS: Avaliar as associações dos anticorpos anti-HLA pré-formados e da compatibilidade HLA à rejeição celular aguda (RCA) em até 90 dias após o transplante. MÉTODOS: Coorte prospectiva de transplantes de fígado ABO compatíveis/idênticos realizados entre janeiro de 2012 e dezembro de 2013. Enxertos que sobreviveram além de 4 dias foram incluídos. A pesquisa de anticorpos anti-HLA classes I e II foram realizadas por meio de ensaios de fase sólida (LABScreen® Mixed e LABScreen® Single Antigen). MFI (Mean Fluorescence Intensity) >= 1.000 foi onsiderado omo positi o para anticorpos anti-HLA. Tipificação HLA-A, B e DR, de receptores e doadores foi feita por meio de PCR (Polymerase Chain Reaction). Conforme o número de alelos HLA incompatíveis, os transplantes foram classificados em compatíveis (0-3 incompatibilidades) e incompatíveis (4-6 incompatibilidades). Apenas episódios de RCA comprovados por biópsia, associados a alterações das provas hepáticas, foram considerados. O critério Banff foi utilizado para diagnóstico e os episódios foram estratificados em leves, moderados e graves. Modelos de regressão de Cox foram realizados e as razões de risco (RR) associadas foram determinadas. Sobrevidas livres de RCA foram obtidas por meio do estimador de Kaplan Meier e comparadas entre os grupos pelo teste log-rank. RESULTADOS: Cento e vinte e nove transplantes foram analisados. Incidência global de RCA em 90 dias foi de 14,7%. A pesquisa de anticorpos anti-HLA pré-formados foi considerada positiva em 35,6% dos transplantes. Em relação à compatibilidade HLA, 91,5% dos transplantes foram classificados como...

Human leucocyte antigens (HLA) molecules are the main targets of rejection in solid organ transplantation. Significance of anti-HLA preformed antibodies and HLA compatibility remains unclear in liver transplantation. Majority of liver transplants are performed without assessment of preformed anti-HLA antibodies and HLA-matching. OBJECTIVES: Evaluate associations of preformed anti-HLA antibodies and HLA compatibility with acute cellular rejection (ACR) in the first 90 days after transplantation. METHODS: Prospective cohort of ABO-identical/compatible liver transplants between January 2012 and December 2013. Grafts that survived more than 4 days were included. Anti-HLA class I and II antibodies were determined by solid phase assays (LABScreen® Mixed and LABScreen® ingle Antigen). A mean fluores en e intensity ( I) >= 1.000 was considered as positive for anti-HLA antibodies. Recipients and donors HLA typing for HLA-A, B and DR were performed using polymerase chain reaction (PCR) assays. According to HLA mismatches (MM), transplants were divided in compatible (0-3 MM) and incompatible (4-6 MM). Only biopsy proven ACR episodes, associated with abnormal liver tests, were considered. Banff criteria was used for diagnosis of ACR and episodes were graded as mild, moderate and severe. Cox proportional hazards models were performed and associated hazard ratios (HR) were determined. Free ACR rates were estimated with Kaplan-Meier analysis and were compared between groups with the log-tank test. RESULTS: One hundred twenty nine transplants were analyzed. Overall incidence of ACR was 14.7% in 90 days. Assessment of anti-HLA pre-formed antibodies was considered positive in 35.6% of transplants. Regarding HLA compatibility, 91.5% were considered incompatible. Anti-HLA antibodies sensitization was associated with an increased risk of ACR (HR= 4.3; CI 95%=1,3 - 13,5; p=0.012). According to class of antibody, we could observe that class II was associated with an...

Características de los pacientes en espera de trasplante renal / Characteristics of patients waiting for kidney transplantation

Los pacientes con insuficiencia renal crónica presentan un marcado descenso de la tasa de filtración glomerular por lo que requieren de terapia de reemplazo renal como la diálisis o el trasplante para sobrevivir. El objetivo del estudio fue determinar las características de los pacientes en lista de espera para trasplante renal. Analizamos 156 pacientes provenientes de diversos centros de diálisis que acudieron al Laboratorio Central de Salud Pública entre julio de 2.013 y agosto de 2.014. Se recolectaron datos demográficos y muestras de sangre para determinar la presencia de anticuerpos anti-HLA por ELISA. Las edades estaban comprendidas entre 4 y 74 años, con un promedio de 40 años. Se registraron pacientes de 15 de las 18 Regiones Sanitarias del país, 50% de los cuales provenían de Asunción y del Departamento Central. La cobertura médica se encontró dividida en partes iguales entre el Ministerio de Salud Pública y el Instituto de Previsión Social. El tiempo promedio en diálisis fue de 34 meses, el 66% de los pacientes fueron poli-transfundidos, el 13% candidatos a retrasplante y el 34% de las mujeres fueron multíparas. El 36% de la población estudiada presentó anticuerpos anti-HLA. Se concluye que los pacientes en espera de trasplante renal se caracterizan por encontrarse en plena edad productiva y por permanecer en diálisis durante varios años. Además, un tercio de esta población se encuentra inmunizada frente a antígenos de histocompatibilidad, lo que dificulta su acceso al trasplante.

Patients with chronic renal failure present a pronounced reduction of the glomerularfiltration rate and therefore, require renal replacement therapy such as dialysis or kidneytransplantation to survive. The aim of this study was to determine the characteristics ofpatients on the waiting list for kidney transplantation. We analyzed 156 patients fromvarious dialysis centers who came to the Central Laboratory of Public Health betweenJuly, 2013 and August, 2014. Demographic information and blood samples were collectedto determine the presence of anti-HLA antibodies by ELISA. Ages were between 4 and 74years, with a mean of 40 years. There were patients from 15 of the 18 health regions ofthe country, 50% of them came from Asunción and the Central Department. Medicalcoverage was found to be divided in equal parts between the Ministry of Public Health andthe Social Security Institute. The mean time on dialysis was 34 months, 66% of thepatients had received multiple blood transfusions, 13% of them were candidates for asecond transplant, and 34% of the women were multiparous. Thirty six percent of thestudied population presented anti-HLA antibodies. The results of this study indicate thatpatients awaiting kidney transplantation in Paraguay are characterized by being at theirproductive age and remain on dialysis for several years. In addition, a third of this population is immunized against histocompatibility antigens, which hinders their access totransplantation.