Variant RHD Types in Brazilians With Discrepancies in RhD Typing.

BACKGROUND: The knowledge of D variants in patients and donors is important because anti-D alloimmunization can occur in some but not all individuals who express a variant RHD allele. Serologic distinction of RhD discrepancies is not always straightforward, which makes molecular analysis highly desirable. METHODS: A group of 223 subjects, 129 patients, and 94 blood donors was identified and analyzed on the basis of a D typing discrepancy. The D antigen expression was evaluated by tube and gel hemagglutination with four anti-D reagents. PCR-single specific primer (SSP), multiplex PCR, RHD BeadChip (Immucor), or sequencing were used for molecular analysis. RESULTS: In total, 168/223 (75%) weak D and 55/223 (25%) partial D variants were identified. Hemagglutination results varied in methods and anti-D reagents used in this process. There was no standard serologic reactivity identified, which could predict what type of D variant would be identified. Among weak D samples, types 1-3 were the most common, while DAR and DVI were most prevalent among partial D samples. CONCLUSION: Our results show that discrepancies found in the serologic typing should be investigated by molecular methods in order to determine the D variant involved and also to distinguish between weak D and partial D. The knowledge of the distribution of weak D types and partial D among populations is important for D- patients and pregnant women management.

One window-period donation in two years of individual donor-nucleic acid test screening for hepatitis B, hepatitis C and human immunodeficiency virus.

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.

Prevalence of erythrocyte alloimmunization in polytransfused patients.

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.

One window-period donation in two years of individual donor-nucleic acid test screening for hepatitis B, hepatitis C and human immunodeficiency virus

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 ...

Incidência de aloimunização eritrocitária em pacientes poli transfundidos / Prevalence of erythrocyte alloimmunization in polytransfused patients

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.