Identification of serologically active Helicobacter pylori antigens related to alterations in serum pepsinogen levels.

Gastric adenocarcinoma is associated with Helicobacter pylori infection. The transition to a carcinogenic process is preceded by glandular atrophy and serum levels of pepsinogen I and II (PGI and PGII) correlate with this type of gastric lesions. Possible associations of serum PG levels in relation to the frequency of serological activity against H. pylori antigens were studied. Serum samples from patients with gastric pathology associated with H. pylori (n=26) and asymptomatic individuals as controls (n=37) were used. Seroactive antigens were identified by immunoblot using a protein extract of H. pylori. The antibody titers anti-H. pylori and the concentration of PGs in serum was determined by ELISA. Thirty-one seroactive antigens were identified, nine of which exhibited a differential frequency between both groups (116.7, 68.8, 61.9, 54.9, 45.6, 38.3, 36.5, 33.8 and 30.1kDa) and only 3 were related to altered levels of PGs in serum. In the control group, the seropositivity of the 33.8kDa antigen was related to an increase in PGII, while the 68.8kDa antigen was related to normal PG values (decreased PGII and elevated PGI/PGII levels) indicating that seropositivity to this antigen could be a protective factor to gastric pathology. The seropositivity of the 54.9kDa antigen was related to altered values of PGs indicative of inflammation and gastric atrophy (increased in PGII and decreased in PGI/PGII). The identification of serum alterations in pepsinogen levels related to seropositivity to H. pylori 33.8, 54.9 and 68.8kDa antigens sets a precedent for further study as possible prognostic serological biomarkers.

Rapid antigen tests for the detection of SARS-CoV-2: A narrative review.

The rapid identificationand isolation of COVID-19 patients has become the cornerstone for the control of the recent outbreak. Real-time quantitative polymerase chain reaction is routinely used to confirm COVID-19 diagnosis and is considered the gold standard due to high sensitivity and specificity. Nevertheless, it usually takes several days and a relatively higher cost. Antigen tests based have emerged to cope with such disadvantages, by offering rapid results, an easy-to-use procedure, and low costs. The objective of the narrative review was to provide up-to-date data about CE-marked rapid antigen tests (RATs) for COVID-19. Given their large number, the study only focused on representative and widely used in Spain (Standard Q, Nadal, Panbio, CerTest, and Wondfo). RATs have become a very useful and validated tool for controlling the spread of COVID-19 allowing the rapid identification of active infection and isolation of positive patients. The present revision of the literature has demonstrated that sensitivity and specificity of all available RATs in Spain are high and accomplish European regulations and WHO recommendations.

[Future applications of mass spectrometry in microbiology]. / Perspectivas de futuro de la espectrometría de masas en microbiología.

MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) has been vigorously introduced in many clinical microbiology laboratories for the rapid and accurate identification of bacteria and fungi. In fact, the implementation of this methodology can be considered a revolution in these laboratories. In addition to microbial identification, MALDI-TOF MS is being used for the detection of some mechanisms of antibiotic resistance and for the molecular typing of bacteria. A number of current and future applications that increase the versatility of this methodology may also be mentioned. Among these are its direct application on clinical samples, the detection of toxins or specific microbial antigens, and its application in the fields of virology and parasitology.

[Microbiological diagnosis of imported malaria]. / Diagnóstico microbiológico de la malaria importada.

Current diagnosis of malaria is based on the combined and sequential use of rapid antigen detection tests (RDT) of Plasmodium and subsequent visualization of the parasite stained with Giemsa solution in a thin and thick blood smears. If an expert microscopist is not available, should always be a sensitive RDT to rule out infection by Plasmodium falciparum, output the result immediately and prepare thick smears (air dried) and thin extensions (fixed with methanol) for subsequent staining and review by an expert microscopist. The RDT should be used as an initial screening test, but should not replace microscopy techniques, which should be done in parallel. The diagnosis of malaria should be performed immediately after clinical suspicion. The delay in laboratory diagnosis (greater than 3 hours) should not prevent the initiation of empirical antimalarial treatment if the probability of malaria is high. If the first microscopic examination and RDT are negative, they must be repeated daily in patients with high suspicion. If suspicion remains after three negative results must be sought the opinion of an tropical diseases expert. Genomic amplification methods (PCR) are useful as confirmation of microscopic diagnosis, to characterize mixed infections undetectable by other methods, and to diagnose asymptomatic infections with submicroscopic parasitaemia.

[Absceso cerebral como manifestación inicial de Deficiencia especifica de anticuerpos].

Background: Specific antibody deficiency (SAD) is an inborn error of immunity, in patients older than 2 years, characterized by normal immunoglobulin levels and IgG subclasses, but with recurrent infections and decreased antibody responses to polysaccharide antigens. Case report: A 10-year-old female, previously healthy, with no significant family history. She is known in this institution for symptoms of headache, vomiting and paresis. A CT scan of the skull was performed, where 4 brain abscesses, edema and displacement of the midline were observed, a right frontal trephine was performed and abscess drainage, antimicrobial management for infectology, blood cultures, Gram staining and cultures of negative drainage material. Assessed for allergy and immunology, for abscesses in deep focus, an approach was performed to rule out inborn error of immunity, immunoglobulins, isohemagglutinins, flow cytometry and response to normal protein antigens. Antibodies against post-vaccination polysaccharide antigens are requested, where a response to only 2 serotypes (18.1% response) is observed, with normal IgG subclasses, a diagnosis of specific antibody deficiency is integrated and management with immuno- globulin at replacement doses is started, as well as annual vaccination with 13 valent. Conclusion: SAD has been considered a problem that can be resolved over time, especially in children, but in others it can evolve into more severe forms of humoral immunodeficiency. Decisions to treat with prophylactic antibiotics and/or gamma globulin are guided by clinical judgment, small studies, and recent consensus documents, which may evolve over time.

Antecedentes: La deficiencia especifica de anticuerpos (SAD) es un error innato de la inmunidad, en pacientes de más de 2 años, caracterizada por niveles de inmunoglobulinas y subclases de IgG normales, pero con infecciones recurrentes y respuestas de anticuerpos disminuidas a antígenos polisacáridos. Reporte de caso: Femenina de 10 años, previa sana, sin antecedentes heredofamiliares de importancia. Conocida en esta institución por cuadro de cefalea, vómi- tos y paresias. Se realiza TAC de cráneo, donde se observan 4 abscesos cerebrales, edema y desplazamiento de la línea media, se realiza trepano frontal derecha y drenaje de abscesos, manejo antimicrobiano por infectología, hemocultivos, tinción de Gram y cultivos de material de drenaje negativos. Valorado por alergia e inmunología, por abscesos en foco profundo, se realizó abordaje para descartar error innato de la inmunidad, inmunoglobulinas, isohemaglutininas, citometría de flujo y respuesta a antígenos proteicos normales. Se solicitan anticuerpos contra antígenos polisacáridos post vacunación, donde se observa respuesta a solo 2 serotipos (respuesta del 18.1%), con subclases de IgG normales, se integra diagnóstico de deficiencia especifica de anticuerpos y se inicia manejo con inmuno- globulina a dosis de reemplazo, asi como vacunación anual con 13 valente. Conclusión: El SAD se ha considerado un problema que puede resolverse con el tiempo, especialmente en niños, pero en otros puede evolucionar hacia formas más severas de inmunodeficiencia humoral. Las decisiones de tratar con antibióticos profilácticos y/o gammaglobulina están guiadas por el juicio clínico, estudios pequeños y documentos de consenso recientes, que pueden evolucionar con el tiempo.

Immune effector cell-associated neurotoxicity syndrome: A therapeutic approach in the critically ill.

Immunotherapy with chimeric antigen-specific receptor modified T cells, known as CAR-T, is emerging as a promising approach to hematological malignancies. In this regard, CAR-T against human cluster of differentiation (CD) 19 has demonstrated antitumor efficacy in application to B cell neoplasms resistant to conventional therapy. However, activation of the immune system induces severe and specific complications which can prove life-threatening. These include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (known as ICANS) - the latter being the subject of the present review. Although the physiopathological mechanisms underlying ICANS are not well known, a number of clinical and biological factors increase the risk of developing neurotoxicity associated to CAR-T therapy. Treatment is based on close monitoring, measures of support, anticonvulsivants, corticosteroids, and early admission to intensive care. The present study offers a comprehensive review of the available literature from a multidisciplinary perspective, including recommendations from intensivists, neurologists and hematologists dedicated to the care of critically ill adults.

[Internal validity of a rapid test for COVID-19 antigens in a nursing home]. / Validez interna de una prueba rápida de detección de antígenos COVID-19 en una residencia de mayores.

INTRODUCTION: RT-qPCR is the reference test for the detection of SARS-CoV-2 infection, however, rapid antigen detection tests (RADT) are now available. In this work, the internal validity of the RADT was evaluated in the context of an outbreak in a nursing home. METHODS: Nasopharyngeal exudate samples were analyzed by RADT and RT-qPCR from 61 residents of a nursing home. The sensitivity and specificity of RADT with respect to RT-qPCR was calculated. RESULTS: Specificity was 100% (95% CI 54.1-100.0), while sensitivity in asymptomatic people was 70.3% (95% CI 53.0-84.1) and in symptomatic people 83.3% (95% CI 51.6-97.9). CONCLUSIONS: The RADTs are sufficiently sensitive and specific to be used as screening tests in nursing homes, especially in situations of outbreaks or suspected outbreaks due to the presence of symptoms.

Celiac disease screening in children and adolescents with type 1 diabetes mellitus: What test should be performed?

INTRODUCTION: Children and adolescents with type 1 diabetes mellitus (T1DM) are at high risk for the development of celiac disease (CD) because of the common genetic characteristics of both conditions. The study objectives were to investigate the frequency of the human leukocyte antigen system (HLA) for CD in pediatric T1DM patients and to determine whether HLA testing is suitable for CD screening in that population and is cost-effective as compared to serological screening for CD. PATIENTS AND METHODS: A retrospective, descriptive study was conducted in 296 patients (148 girls; 148 boys) with T1DM aged <18 years who attended a Madrid hospital. Data on the frequency of genotypes DQ2/DQ8 in a subgroup of 92 patients and the additional cost of performing HLA typing for screening CD were collected. Only when the risk HLA haplotype (DQ2/DQ8) is negative no further serological screening for CD is required. RESULTS: Twenty-three patients with T1DM (7.77%) also had CD. Alleles DQ2 or DQ8 were found in 91.3% of patients in whom the HLA haplotype was studied. Thus, only 8.7% with a negative haplotype would have benefited from HLA testing. The additional cost of HLA typing was € 105.2 for each patient with positive DQ2 or DQ8 in our population. CONCLUSIONS: HLA typing is not a cost-effective screening method for CD in T1DM because of the frequent association of T1DM with risk genotypes for CD.

Celiac disease screening in children and adolescents with type1 diabetes mellitus: What test should be performed? / Cribado de enfermedad celiaca en niños y adolescentes con diabetes mellitus tipo1: ¿qué estrategia utilizar?

INTRODUCTION: Children and adolescents with type1 diabetes mellitus (T1DM) are at high risk for the development of celiac disease (CD) because of the common genetic characteristics of both conditions. The study objectives were to investigate the frequency of the human leukocyte antigen system (HLA) for CD in pediatric T1DM patients and to determine whether HLA testing is suitable for CD screening in that population and is cost-effective as compared to serological screening for CD. PATIENTS AND METHODS: A retrospective, descriptive study was conducted in 296 patients (148 girls; 148 boys) with T1DM aged <18years who attended a hospital in Madrid. Data on the frequency of genotypes DQ2/DQ8 in a subgroup of 92 patients and the additional cost of performing HLA typing for screening CD were collected. Only when the risk HLA haplotype (DQ2/DQ8) is negative no further serological screening for CD is required. RESULTS: Twenty-three patients with T1DM (7.77%) also had CD. Alleles DQ2 or DQ8 were found in 91.3% of patients in whom the HLA haplotype was studied. Thus, only 8.7% with a negative haplotype would have benefited from HLA testing. The additional cost of HLA typing was €105.2 for each patient with positive DQ2 or DQ8 in our population. CONCLUSIONS: HLA typing is not a cost-effective screening method for CD in T1DM because of the frequent association of T1DM with risk genotypes for CD.

Autoantibodies to extractable nuclear antigens (ENAs) pattern in rheumatoid arthritis patients: Relevance and clinical implications.

OBJECTIVES: To study the frequency of different autoantibodies to extractable nuclear antigens (ENAs) in rheumatoid arthritis (RA) patients and to correlate findings with clinical manifestations, disease activity and radiological damage. METHODS: A total of 230 RA patients were included and 75 healthy controls. In all patients rheumatological assessment was done and routine laboratory investigations and immune profile were performed in both patients and controls, including: RF, ACPA, ANA and anti-ENAs (Ro/SSA, La/SSB, U1-RNP, anti-Jo-1 and anti-Sm). Radiological damage was scored using Sharp/van der Heijde, and disease activity was evaluated by DAS28-ESR and DAS28-CRP. RESULTS: RF was positive in 101 (43.9%), ACPA in 220 (95.7%), ANA in 58 (25.2%), anti Ro in 31 (13.5%), anti-La in 10 (4.3%), anti-Jo1 in 5 (2.2%) and anti-RNP in 2 (0.9%). Anti-Ro/SSA positively correlated with sicca symptoms (p=.02), RF titer (p<.001), ANA (p<.001), DAS28-ESR (p=.026), and DAS28-CRP (p=.003). Anti-La antibodies correlated positively with SJC (p=.001), TJC (p=.001), ANA (p<.001), DAS-28 ESR (p=.007). Anti-Jo-1 correlated positively with interstitial lung disease (ILD) (p≤.001), RF titer (p=.037) and ANA (p≤.001). Anti-RNP antibodies correlated positively with disease duration (p≤.001), ACPA titer (p≤.001) and ANA (p=.014). In the controls ANA was positive in two (2.7%), anti-Ro in three (4%), and none of the controls tested positive for other autoantibodies. CONCLUSIONS: In RA patients, positive ANA is frequent and positively associated with anti-Ro, anti-La and anti-Jo1 autoantibodies. Screening for autoantibodies against other anti-ENAs seems mandatory in RA patients especially when ANA is positive. RA cases with positive Anti-Jo-1 may develop anti synthetase syndrome and ILD.

Immune effector cell-associated neurotoxicity syndrome: A therapeutic approach in the critically ill. / Síndrome de neurotoxicidad asociada a células inmunoefectoras: un enfoque terapéutico en el paciente crítico.

Immunotherapy with chimeric antigen-specific receptor modified T cells, known as CAR-T, is emerging as a promising approach to hematological malignancies. In this regard, CAR-T against human cluster of differentiation (CD) 19 has demonstrated antitumor efficacy in application to B cell neoplasms resistant to conventional therapy. However, activation of the immune system induces severe and specific complications which can prove life-threatening. These include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (known as ICANS) - the latter being the subject of the present review. Although the physiopathological mechanisms underlying ICANS are not well known, a number of clinical and biological factors increase the risk of developing neurotoxicity associated to CAR-T therapy. Treatment is based on close monitoring, measures of support, anticonvulsivants, corticosteroids, and early admission to intensive care. The present study offers a comprehensive review of the available literature from a multidisciplinary perspective, including recommendations from intensivists, neurologists and hematologists dedicated to the care of critically ill adults.

Nefropatía membranosa: genética, antígenos y anticuerpos

La nefropatía membranosa es un trastorno renal caracterizado por el engrosamiento de la membrana basal glomerular, que causa el síndrome nefrótico. Puede deberse a diversas afecciones subyacentes que provocan daños en las unidades de filtración de los riñones, conocidas como nefronas, produciendo proteinuria masiva, hipoalbuminemia, edema e hiperlipidemia. Entre el 30 y el 40% de los casos de síndrome nefrótico en adultos se deben a una nefropatía membranosa. En las últimas décadas se ha avanzado en el descubrimiento de antígenos, anticuerpos y genes implicados en la fisiopatología de la enfermedad y se ha propuesto un nuevo sistema de clasificación. La presencia de complejos antígeno-anticuerpo junto con factores genéticos puede influir en la susceptibilidad a dicha desregulación inmunológica, y establece nueva información en un lo que se conocía entre las etiologías de causas primarias y secundarias.La comprensión de los antígenos implicados en la nefropatía membranosa es un área de investigación activa, y es posible que se identifiquen antígenos adicionales a medida que nuestro conocimiento de la enfermedad siga evolucionando. Este artículo resume algunos conceptos y hallazgos recientes sobre este tema. (provisto por Infomedic International)

Membranous nephropathy is a kidney disorder characterized by thickening of the glomerular basement membrane, that causes nephrotic syndrome. It can be caused by various underlying conditions that result in damage to the filtering units of the kidneys, known as nephrons, producing massive proteinuria, hypoalbuminemia, edema and hyperlipidemia.  Between 30 to 40% of cases of nephrotic syndrome in adults are due to membranous nephropathy. In recent decades, progress has been made with the discovery of antigens, antibodies and genes involved in the pathophysiology of the disease and a new classification system has been proposed. The presence of antigen-antibody complexes together with genetic factors may influence the susceptibility to such immune dysregulation, and states new information in a what was known between the etiologies of primary and secondary causes. The understanding of the antigens involved in membranous nephropathy is an area of active research, and additional antigens may be identified as our knowledge of the disease continues to evolve. This article summarizes some concepts and recent findings made on this topic. (provided by Infomedic International)

Identifying molecularly defined antigens for a Histoplasma capsulatum-specific interferon gamma release assay.

BACKGROUND: In a previous work we showed the feasibility of an interferon gamma release assay (IGRA) for detecting latent infection by Histoplasma capsulatum. While in that proof-of-concept study we used crude fungal extracts as antigens, the newest IGRAs developed for other infections are based on molecularly defined antigens, mostly on mixtures of immunogenic peptides. AIMS: To identify proteins in H. capsulatum that might serve as molecularly defined antigens for an IGRA test. METHODS: We surveyed the literature looking for known H. capsulatum-immunogenic proteins and assayed two of them as antigens in an IGRA test, in a study that involved 80 volunteers. Furthermore, we used several bioinformatics tools to identify specific H. capsulatum proteins and to analyze possible strategies for the design of H. capsulatum-specific immunogenic peptides. RESULTS: Seven H. capsulatum-immunogenic proteins were retrieved from the literature. IGRA tests using either the heat shock protein 60 or the M antigen showed high sensitivities but low specificities, most likely due to the high sequence similarity with the corresponding orthologs in other pathogenic microorganisms. We identified around 2000 H. capsulatum-specific proteins, most of which remain unannotated. Class II T-cell epitope predictions for a small number of these proteins showed a great variability among different alleles, prompting for a "brute force" approach for peptide design. CONCLUSIONS: The H. capsulatum genome encodes a large number of distinctive proteins, which represent a valuable source of potential specific antigens for an IGRA test. Among them, the Cfp4 protein stands out as a very attractive candidate.

Relación entre la compatibilidad del HLA y la pérdida del injerto en trasplante renal de donante cadavérico: Un análisis por propensity score matching en Colombia / Relationship between HLA compatibility and graft loss in renal transplant from a deceased donor: An analysis by propensity score matching in Colombia

Introducción. En Colombia, solo un 24 % de los pacientes en lista recibieron un trasplante renal, la mayoría de donante cadavérico. Para la asignación de órganos se considera el HLA A-B-DR, pero la evidencia reciente sugiere que el HLA A-B no está asociado con los desenlaces del trasplante. El objetivo de este estudio fue evaluar la relevancia del HLA A-B-DR en la sobrevida del injerto de los receptores de trasplante renal. Métodos. Estudio de cohorte retrospectivo que incluyó pacientes trasplantados renales con donante cadavérico en Colombiana de Trasplantes, desde 2008 a 2023. Se aplicó un propensity score matching (PSM) para ajustar las covariables en grupos de comparación por compatibilidad y se evaluó la relación del HLA A-B-DR con la sobrevida del injerto renal por medio de la prueba de log rank y la regresión de Cox. Resultados. Se identificaron 1337 pacientes transplantados renales, de los cuales fueron mujeres un 38,7 %, con mediana de edad de 47 años y de índice de masa corporal de 23,8 kg/m2. Tras ajustar por PSM las covariables para los grupos de comparación, la compatibilidad del HLA A-B no se relacionó significativamente con la pérdida del injerto, con HR de 0,99 (IC95% 0,71-1,37) para HLA A y 0,75 (IC95% 0,55-1,02) para HLA B. Solo la compatibilidad por HLA DR fue significativa para pérdida del injerto con un HR de 0,67 (IC95% 0,46-0,98). Conclusión. Este estudio sugiere que la compatibilidad del HLA A-B no influye significativamente en la pérdida del injerto, mientras que la compatibilidad del HLA DR sí mejora la sobrevida del injerto en trasplante renal con donante cadavérico

Introduction. In Colombia, only 24% of patients on the waiting list received a renal transplant, most of them from cadaveric donors. HLA A-B-DR is considered for organ allocation, but recent evidence suggests that HLA A-B is not associated with transplant outcomes. The objective of this study was to evaluate the relevance of HLA A-B-DR on graft survival in kidney transplant recipients. Methods. Retrospective cohort study that included kidney transplant recipients with a cadaveric donor in Colombiana de Trasplantes from 2008 to 2023. A propensity score matching (PSM) was applied to adjust the covariates in comparison groups for compatibility, and the relationship of HLA A-B-DR with kidney graft survival was evaluated using the log rank test and Cox regression. Results. A total of 1337 kidney transplant patients were identified; of those, 38.7% were female, with median age of 47 years, and BMI 23.8 kg/m2. After adjusting the covariates with PSM for the comparison groups, HLA A-B matching was not significantly related to graft loss, with HR of 0.99 (95% CI 0.71-1.37) and 0.75 (95% CI 0.55-1.02), respectively. Only HLA DR matching was significant for graft loss with an HR of 0.67 (95% CI 0.46-0.98). Conclusions. This study suggests that HLA A-B matching does not significantly influence graft loss, whereas HLA DR matching does improve graft survival in renal transplantation with a cadaveric donor.

Importancia de las determinaciones inmunohematológicas en el control prenatal de gestantes con grupo sanguíneo RhD negativo

La guía para la atención prenatal es el marco regulatorio de las normas de obstetricia para el control y cuidado de las gestantes, con énfasis en aquellas que poseen el grupo sanguíneo RhD negativo. La aloinmunización por anti-D es la causa más frecuente y grave de la enfermedad hemolítica del recién nacido. Para un diagnóstico temprano de la embarazada con dicho grupo sanguíneo, resulta necesario determinar los anticuerpos antieritrocitarios involucrados. En la presente comunicación se resalta la función del laboratorio de inmunohematología en el seguimiento de la gestante con grupo de sangre RhD negativo.

The guide for prenatal care is the regulatory mark of obstetrics norms for the control and care of pregnant women, with emphasis on those who have the RhD negative blood group. Alloimmunization by anti-D is the most frequent and serious cause of hemolytic disease of the newborn. For an early diagnosis of the pregnant woman with said blood group, it is necessary to determine the red blood cell antibodies involved. This communication highlights the role of the immunohematology laboratory in the follow-up of pregnant woman with RhD negative blood type.

Fast protocol for the production of Histoplasma capsulatum antigens for antibody detection in the immunodiagnosis of histoplasmosis.

BACKGROUND: Current methods for the production of Histoplasma capsulatum antigens are problematic in terms of standardization, specificity, stability, repeatability and reproducibility. AIMS: In this study, we sought to optimize the methodology for producing H. capsulatum antigens, and to evaluate its applicability. METHODS: Antigenic preparations obtained from 12 H. capsulatum isolates were evaluated by double immunodiffusion and immunoblotting assays against homologous and heterologous sera. RESULTS: The evaluated and optimized protocol allowed a more stable production, as well as repeatable, reproducible, with shorter culture time and less costly. By double immunodiffusion and immunoblotting assays, the best pattern of reactivity was observed for antigens obtained with 33 days of culture from the isolates 200 and 406 against the M antigen and for the isolate 200 with 15 days against H antigen. The SDS-PAGE presented antigenic components of molecular masses between 17 and 119kDa. The immunoblotting sensitivity was 95.5% and 100% with histoplasmosis sera from ill patients and sera from H. capsulatum infected but otherwise healthy patients, respectively, to the antigen derived from isolates 200 and 406. CONCLUSIONS: We suggest the employment of the antigen from isolate 200, with 15 or 30 days of culture, in the double immunodiffusion and immunoblotting assays due to its good ability to discriminate both sera from patients with histoplasmosis illness and histoplasmosis infection, in addition to its high specificity against heterologous sera.

Acerca de las reacciones hemolíticas tardías / About delayed hemolytic transfusion reactions

Introducción: las reacciones hemolíticas tardías transfusionales ocurren después de 24 horas de practicadas, algunas durante las dos semanas siguientes a la transfusión o hasta en un período de 30 días. Las reacciones transfusionales inmunológicas pueden ser febriles, anafilácticas y hemolíticas. En este último nivel se presentan como reacción a antígenos de eritrocitos extraños en pacientes que fueron expuestos previamente a transfusiones y embarazo. Reporte de caso: a continuación revisaremos el caso de una paciente en el Hospital de San José de Bogotá quien presentó una reacción hemolítica tardía y se documentó la expresión de antígenos Duffy y antígenos E, secundarios a inmunización por trasfusiones anteriores.

Introducction: delayed hemolytic transfusion reactions (DHTR) happen 24 hours, two weeks or up to 30 days post transfusion. Immunologic transfusion reactions may be febrile, anaphylactic and hemolytic. Hemolysis occurs as a response to foreign red-blood cells antigens, in patients, previously exposed to transfusions and pregnancy. Case presentation: herein we review the case of a patient, admitted to Hospital de San José in Bogotá, who presented with a delayed hemolytic reaction, in whom the expression of Duffy and E antigens was documented, secondary to immunization related to previous blood transfusions.

Factors interfering with the production of Histoplasma capsulatum antigens / Fatores que interferem na produção de antígenos de Histoplasma capsulatum

Histoplasma capsulatum causes systemic mycosis that depends on host susceptibility, fungal virulence, and factors associated with the infectious process. We evaluated the possible interference of the phenotype of 12 samples of H. capsulatum isolated from HIV-positive and negative patients in obtaining antigens, aiming at the serological diagnosis through the gender-specific recognition of the H and M fractions. The antigens were evaluated by double immunodiffusion against H. capsulatum anti-antigen polyclonal antibody and serum samples from patients with histoplasmosis.The phenotypic evaluation revealed differences in the identification of the fungal agent and in the expression of H and M antigens, considered serological markers of the disease, associated with pigmentation and the production of conidia. It was found that antigenic preparations obtained from H. capsulatum isolated from HIV-positive patients may have satisfactory antigenic capacity. The patient's immune status does not seem to interfere with the expression of antigenic proteins secreted by H. capsulatum. However, we suggest that prolonged use of antiretrovirals drugs or steroids can cause important phenotypic alterations. We showed that some fungal samples from patients with a long history of immunosuppressive drugs produced atypical cellular elements and low reactivity against the H and M fractions. (AU)

Histoplasma capsulatum causa micose sistêmica endêmica que depende da suscetibilidade do hospedeiro, da virulência fúngica e de fatores associados ao processo infeccioso. Avaliamos a possível interferência do fenótipo de 12 amostras de H. capsulatumisolados de pacientes HIV positivos e negativos na obtenção de antígenos, visando o diagnóstico sorológico por meio do reconhecimento gênero-específico das frações H e M. Os antígenos foram avaliados por imunodifusão dupla, frente a anticorpo policlonal anti-antígeno de H. capsulatum e frente a amostras de soro de pacientes com histoplasmose. A avaliação fenotípica revelou diferenças, não só na identificação do agente fúngico, mas também na expressão dos antígenos H e M, considerados marcadores sorológicos da doença, associados à pigmentação e produção de conídios. Verificou-se que preparações antigênicas obtidas de H. capsulatum isoladas de pacientes HIV positivos podem ter capacidade antigênica satisfatória. O estado imunológico do paciente parece não interferir na expressão de proteínas antigênicas secretadas por H. capsulatum. No entanto, sugerimos que o uso prolongado de antirretrovirais e/ou esteróides pode causar alterações fenotípicas importantes. Verificou-se que algumas amostras fúngicas isoladas de pacientes com longo histórico de uso de imunossupressores produziram elementos celulares atípicos e baixa reatividade sorológica contra as frações H e M de H. capsulatum. (AU)

Identification of serologically active Helicobacter pylori antigens related to alterations in serum pepsinogen levels / Identificación de antígenos de Helicobacter pylori serológicamente activos relacionados con alteraciones en los niveles de pepsinógenos en suero

Resumen El adenocarcinoma gástrico se asocia con la infección por Helicobacter pylori. La transición a un proceso de carcinogénesis está precedida por atrofia glandular, y los niveles séricos de pepsinógeno I y II (PGI y PGII) se correlacionan con este tipo de lesiones gástricas. El objetivo del trabajo fue estudiar posibles asociaciones de los niveles de pepsinógenos (PG) en suero en relación con la frecuencia de actividad serológica hacia antígenos de H. pylori. Se utilizaron muestras de suero de pacientes con patología gástrica asociada a H. pylori (n = 26) y de individuos asintomáticos como controles (n = 37). Los antígenos seroactivos se identificaron mediante inmunoblot utilizando un extracto proteico de H. pylori. Los títulos de anticuerpos anti-H. pylori y la concentración de PG en suero se determinaron por ELISA. De los 31 antígenos seroactivos identificados, 9 presentaron una frecuencia diferencial entre ambos grupos (116,7; 68,8; 61,9; 54,9; 45,6; 38,3; 36,5; 33,8 y 30,1 kDa) y solo 3 se relacionaron con niveles alterados de PG en suero. En el grupo control, la seropositividad del antígeno de 33,8 kDa se relacionó con un aumento de PGII, mientras que el antígeno de 68,8kDa se relacionó con valores normales de PG (PGII disminuido y PGI/PGII elevado), sugiriendo que la seropositividad a este antígeno podría ser un factor protector frente a patologías gástricas. La seropositividad del antígeno de 54,9 kDa se relacionó con valores alterados de PG indicadores de inflamación y atrofia gástrica (aumento de PGII y disminución de PGI/PGII). La identificación de alteraciones séricas en los niveles de pepsinógeno relacionadas con la seropositividad a los antígenos de 33,8; 54,9 y 68,8 kDa de H. pylori sienta un precedente para futuros estudios como posibles biomarcadores serológicos pronósticos.

Collapsing glomerulonephritis with podocyte markers in hemophagocytic syndrome secondary to hepatosplenic T-cell lymphoma / [Glomerulonefritis colapsante con marcadores de desdiferenciación podocitaria en síndrome hemofagocítico secundario a linfoma hepatoesplénico de células T].

The hemophagocytic syndrome is a serious clinical-histological entity secondary to different diseases. Collapsing glomerulonephritis is a proliferative podocytopathy that usually has an unfavorable renal prognosis. We present a case in which both entities were associated, which is an infrequent form of hepatosplenic T-cell lymphoma. In addition, we review the role of the markers of podocyte dedifferentiation in this glomerulopathy and its pathophysiology and treatment.

El síndrome hemofagocítico es una condición clínica e histológica grave, secundaria a diferentes procesos. La glomerulonefritis colapsante es una podocitopatía proliferativa, generalmente de pronóstico desfavorable para la función renal. Se presenta un caso en el que las dos condiciones aparecieron asociadas, lo cual es una forma infrecuente de presentación del linfoma hepatoesplénico de células T. Se discute, asimismo, el papel de los marcadores de desdiferenciación podocitaria en esta glomerulopatía, y se revisan la fisiopatología y el tratamiento.