RESUMEN

Neonatal alloimmune thrombocytopenia is a serious disease, in which the mother produces antibodies against fetal platelet antigens inherited from the father; it is still an underdiagnosed disease. This disease is considered the platelet counterpart of the RhD hemolytic disease of the fetus and newborn, yet in neonatal alloimmune thrombocytopenia the first child is affected with fetal and/or neonatal thrombocytopenia. There is a significant risk of intracranial hemorrhage and severe neurological impairment, with a tendency for earlier and more severe thrombocytopenia in subsequent pregnancies. This article reports a case of neonatal alloimmune thrombocytopenia in the second pregnancy affected and discusses diagnosis, management and the clinical importance of this disease.

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RESUMEN

Neonatal alloimmune thrombocytopenia is a serious disease, in which the mother produces antibodies against fetal platelet antigens inherited from the father; it is still an underdiagnosed disease. This disease is considered the platelet counterpart of the RhD hemolytic disease of the fetus and newborn, yet in neonatal alloimmune thrombocytopenia the first child is affected with fetal and/or neonatal thrombocytopenia. There is a significant risk of intracranial hemorrhage and severe neurological impairment, with a tendency for earlier and more severe thrombocytopenia in subsequent pregnancies. This article reports a case of neonatal alloimmune thrombocytopenia in the second pregnancy affected and discusses diagnosis, management and the clinical importance of this disease.

A púrpura trombocitopênica neonatal aloimune é uma doença grave, na qual a mãe produz anticorpos contra antígenos plaquetários fetais herdados do pai, e é ainda subdiagnosticada na prática clínica. É considerada o equivalente plaquetário da doença hemolítica do recém-nascido, com a diferença que o primeiro filho é afetado, apresentando trombocitopenia fetal e/ou neonatal. Há risco significativo de hemorragia intracraniana e sequelas neurológicas graves, com tendência a trombocitopenia mais grave e mais precoce nas gestações subsequentes. Este artigo relata um caso de trombocitopenia aloimune neonatal na segunda gestação afetada e discute diagnóstico, manejo e importância clínica dessa doença na prática clínica.

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OBJECTIVE: To describe general data on nucleic acid/serology testing and report the first hepatitis B-nucleic acid testing yield case of an immunized donor in Brazil. METHODS: A total of 24,441 donations collected in 2010 and 2011 were submitted to individual nucleic acid testing for hepatitis B, hepatitis C and human immunodeficiency virus using the TaqMan((r)) MPX kit (Roche) on the Cobas s201 platform, in addition to routine screening for serological markers. Nucleic acid testing-reactive donations were further evaluated by real-time polymerase chain reaction using Cobas AmpliPrep/Cobas TaqMan hepatitis B virus, hepatitis C virus and human immunodeficiency virus tests. RESULTS: Thirty-two donations were reactive by nucleic acid testing, 31 were also serologically reactive and one first-time donor was identified as having hepatitis B in the window period. Follow-up samples showed increasing titers of anti-HBs rising from 19 UI/mL in the index donation to 109 IU/mL seven months later attributable to his vaccination history. Curiously, this donor was never reactive for HbsAg nor for anti-HBc. In the yield donation, he was concomitantly reactive for syphilis (enzyme immunoassay and fluorescent treponemal antibody-absorption; venereal disease research laboratory non-reactive). Overall, six donors (0.02%) were characterized as occult hepatitis B. A total of 35% of the confirmed (recombinant immunoblot assay positive) hepatitis C donations were nucleic acid testing non-reactive and no human immunodeficiency virus "elite controller" was identified. CONCLUSION: The yield rate (1:24,441; 95% confidence interval: 1:9,537 - 1:89,717) contrasts to the North American rate (1:410,540 donations) and strongly advocates the adoption of nucleic acid testing for hepatitis B in Brazil despite the increasing rate of anti-HBs reactive subjects due to the successful immunization program.

RESUMEN

Objective: To describe general data on nucleic acid/serology testing and report the first hepatitis B-nucleic acid testing yield case of an immunized donor in Brazil. Methods: A total of 24,441 donations collected in 2010 and 2011 were submitted to individual nucleic acid testing for hepatitis B, hepatitis C and human immunodeficiency virus using the TaqMan® MPX kit (Roche) on the Cobas s201 platform, in addition to routine screening for serological markers. Nucleic acid testing-reactive donations were further evaluated by real-time polymerase chain reaction using Cobas AmpliPrep/Cobas TaqMan hepatitis B virus, hepatitis C virus and human immunodeficiency virus tests. Results: Thirty-two donations were reactive by nucleic acid testing, 31 were also serologically reactive and one first-time donor was identified as having hepatitis B in the window period. Follow-up samples showed increasing titers of anti-HBs rising from 19 UI/mL in the index donation to 109 IU/mL seven months later attributable to his vaccination history. Curiously, this donor was never reactive for HbsAg nor for anti-HBc. In the yield donation, he was concomitantly reactive for syphilis (enzyme immunoassay and fluorescent treponemal antibody-absorption; venereal disease research laboratory non-reactive). Overall, six donors (0.02%) were characterized as occult hepatitis B. A total of 35% of the confirmed (recombinant immunoblot assay positive) hepatitis C donations were nucleic acid testing non-reactive and no human ...

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Objective: To determine the incidence and the rate of red blood cell alloimmunization in polytransfused patients. Methods: A polytransfused patient was defined as having received at least 6 units of red cell concentrates during a 3-month period. The recordsof all patients (n = 12,904) who had received red blood cell units were examined retrospectively by searching the computer database at Hospital Israelita Albert Einstein in São Paulo, Brazil, over a 6-year period, between 2003 and 2009. Results: During this time, 77,049 red cell concentrate transfusions were performed in 12,904 patients. There were 3,044 polytransfused patients, 227 of whom (7.5%) presented with irregular erythrocyte antibodies. The prevalence of alloantibody specificity was: Anti-E>anti-D>anti-K>anti-C>anti-Dia>anti-c>anti-Jka>anti-S in 227 polytransfused patients. We found combinations of alloantibodies in 79 patients (34.8%), and the most commonspecificities were against the Rh and/or Kell systems. These antibodies show clinical significance, as they can cause delayed hemolytic transfusion reactions and perinatal hemolytic disease. About 20% of the patients showed an IgG autoantibody isolatedor combined with alloantibodies. Interestingly, a high incidence of antibodies against low frequency antigens was detected in this study, mainly anti-Dia. Conclusion: Polytransfused patients have a high probability of developing alloantibodies whetheralone or combined with autoantibodies and antibodies against low frequency antigens. Transfusion of red blood cells with a phenotype-compatible with RH (C, E, c), K, Fya, and Jka antigens is recommended for polytransfused patients in order to preventalloimmunization and hemolytic transfusion reactions.

Objetivo: Determinar a incidência e a taxa de aloimunização eritrocitária em pacientes politransfundidos. Métodos: Foram classificados como politransfundidos todos os pacientes que receberam no mínimo 6 unidades de concentrado de hemácias no período de 3 meses. Foram examinados retrospectivamente os prontuários de todos os pacientes(n = 12.904) que receberam transfusões de unidades de hemácias procurados nas bases de dados computadorizados do Hospital Israelita Albert Einstein, em São Paulo (SP), no período de 6 anos, entre 2003 e 2009. Resultados: Nesse período foram realizadas 77.049 transfusões de concentrado de hemácias em 12.904 pacientes. Os pacientes politransfundidos totalizaram 3.044, sendo que 227 (7,5%) apresentam anticorpos eritrocitários irregulares. A prevalência da especificidade dos aloanticorpos encontrados nos 227 pacientes politransfundidos foi: Anti-E>anti-D>anti-K>anti-C>anti-Dia>antic>anti-Jka>anti-S. Em 79 pacientes (34,8%) foram encontradas associações de aloanticorpos e as combinações mais freqüentes foram dos anticorpos dos sistemas Rh e/ou Kell. Esses anticorpos têm importância clínica, pois podem causar reações transfusionais hemolíticas tardias e doença hemolítica perinatal. Cerca de 20% dos pacientes apresentavam autoanticorpo IgG isolado ou em associação com aloanticorpos. Um achado interessante neste estudo foi a alta incidência de anticorpos contra antígenos de baixa frequência, com predomínio anti-Dia. Conclusão: Pacientes politransfundidos têm alta probabilidade de desenvolver aloanticorpos isolados ou em associação com autoanticorpos e anticorpos contra antígenos de baixa frequência. A transfusão de concentrado de hemácias com fenótipo compatível para os antígenos RH (C, E, c), K, Fya, e Jka deve ser recomendada para o grupo de pacientes politransfundidos, com objetivo de evitar a aloimunização e a reação transfusional hemolítica.

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OBJECTIVE: To determine the incidence and the rate of red blood cell alloimmunization in polytransfused patients. METHODS: A polytransfused patient was defined as having received at least 6 units of red cell concentrates during a 3-month period. The records of all patients (n = 12,904) who had received red blood cell units were examined retrospectively by searching the computer database at Hospital Israelita Albert Einstein in São Paulo, Brazil, over a 6-year period, between 2003 and 2009. RESULTS: During this time, 77,049 red cell concentrate transfusions were performed in 12,904 patients. There were 3,044 polytransfused patients, 227 of whom (7.5%) presented with irregular erythrocyte antibodies. The prevalence of alloantibody specificity was: Anti-E>anti-D>anti-K>anti-C>anti-Dia>anti-c>anti-Jka>anti-S in 227 polytransfused patients. We found combinations of alloantibodies in 79 patients (34.8%), and the most common specificities were against the Rh and/or Kell systems. These antibodies show clinical significance, as they can cause delayed hemolytic transfusion reactions and perinatal hemolytic disease. About 20% of the patients showed an IgG autoantibody isolated or combined with alloantibodies. Interestingly, a high incidence of antibodies against low frequency antigens was detected in this study, mainly anti-Dia. CONCLUSION: Polytransfused patients have a high probability of developing alloantibodies whether alone or combined with autoantibodies and antibodies against low frequency antigens. Transfusion of red blood cells with a phenotype-compatible with RH (C, E, c), K, Fya, and Jka antigens is recommended for polytransfused patients in order to prevent alloimmunization and hemolytic transfusion reactions.