Significado do anti-HBc isolado em doadores de sangue de São Paulo

The clinical significance of isolated anti-HBc is still a challenge. To elucidate the real importance of this finding in our blood donors, an investigation algorithm was tested. One hundred and twelve isolated anti-HBc seropositive blood donors underwent clinical evaluation and retesting of HBV markers. Those who presented repeatedly reactive isolated anti-HBc, received a single dose of hepatitis B recombinant vaccine to verify anti-HBs early response. A HBV-DNA determination by PCR was done for those who did not test positive to anti-HBs after vaccine. The level of anti-HBc was recorded as a ratio of the sample-to-cut-off values (S:C ratio) in 57 candidates at donation. Comparing true and false-positive anti-HBc results, the different S:C ratios of them were statistically significant and when less than 2, implying in a false-positive result probability over 80%. A high percent of false-positive results (16.07%) was verified after anti-HBc retesting. HBV immunity was characterized in 49.11%, either by anti-HBs detection in retesting (15.18%), or after a single dose HBV vaccination (33.93%). HBV-DNA was negative in all tested donors. In conclusion, this algorithm was useful to clarify the meaning of isolated anti-HBc in most of our blood donors.O significado do anti-HBc isolado continua a ser tema relevante para aqueles envolvidos com o atendimento a doadores de sangue soropositivos. Um algoritmo de investigação foi testado com o objetivo de avaliar em nosso meio o real diagnóstico desses doadores. Cento e doze doadores com anti-HBc isolado foram submetidos a avaliação clínico-epidemiológica e testes sorológicos para o VHB. Aqueles confirmadamente anti-HBc isolado, receberam dose única da vacina recombinante contra o VHB, e após 30 dias foi pesquisada a formação do anti-HBs. Naqueles que não formaram anti-HBs após vacina, foi realizada a pesquisa do HBV-DNA por PCR. O índice do "cut-off" sobre a densidade ótica foi determinado em 57 indivíduos por ocasião da doação. Na comparação entre falsos e verdadeiros anti-HBc positivos, o índice C.O./D.O. mostrou significância estatística. Assim quando este índice foi menor que 2, a possibilidade de resultado falso-positivo foi de 83,33%. Verificamos ainda elevada porcentagem de resultados falsos-positivos (16,07%) após a simples repetição do anti-HBc. Imunidade ao VHB pôde ser caracterizada em 49,11%, tanto pela detecção do anti-HBs nos testes de repetição (15,18%) quanto pela vacinação em dose única contra a hepatite B (33,93%). O HBV-DNA foi negativo em todos os doadores testados. Concluímos que este algorítmo foi útil para esclarecer o significado do anti-HBc isolado na maioria dos doadores de sangue estudados

Significance of isolated hepatitis B core antibody in blood donors from São Paulo

The clinical significance of isolated anti-HBc is still a challenge. To elucidate the real importance of this finding in our blood donors, an investigation algorithm was tested. One hundred and twelve isolated anti-HBc seropositive blood donors underwent clinical evaluation and retesting of HBV markers. Those who presented repeatedly reactive isolated anti-HBc, received a single dose of hepatitis B recombinant vaccine to verify anti-HBs early response. A HBV-DNA determination by PCR was done for those who did not test positive to anti-HBs after vaccine. The level of anti-HBc was recorded as a ratio of the sample-to-cut-off values (S:C ratio) in 57 candidates at donation. Comparing true and false-positive anti-HBc results, the different S:C ratios of them were statistically significant and when less than 2, implying in a false-positive result probability over 80%. A high percent of false-positive results (16.07%) was verified after anti-HBc retesting. HBV immunity was characterized in 49.11%, either by anti-HBs detection in retesting (15.18%), or after a single dose HBV vaccination (33.93%). HBV-DNA was negative in all tested donors. In conclusion, this algorithm was useful to clarify the meaning of isolated anti-HBc in most of our blood donors

Contribution of the Retrovirus Epidemiology Donor Study (REDS) to research on blood transfusion safety in Brazil

The Retrovirus Epidemiology Donor Study (REDS) program was established in the United States in 1989 with the purpose of increasing blood transfusion safety in the context of the HIV/AIDS and human T-lymphotropic virus epidemics. REDS and its successor, REDS-II were at first conducted in the US, then expanded in 2006 to include international partnerships with Brazil and China. In 2011, a third wave of REDS renamed the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) was launched. This seven-year research program focuses on both blood banking and transfusion medicine research in the United States of America, Brazil, China, and South Africa. The main goal of the international programs is to reduce and prevent the transmission of HIV/AIDS and other known and emerging infectious agents through transfusion, and to address research questions aimed at understanding global issues related to the availability of safe blood. This article describes the contribution of REDS-II to transfusion safety in Brazil. Articles published from 2010 to 2013 are summarized, including database analyses to characterize blood donors, deferral rates, and prevalence, incidence and residual risk of the main blood-borne infections. Specific studies were developed to understand donor motivation, the impact of the deferral questions, risk factors and molecular surveillance among HIV-positive donors, and the natural history of Chagas disease. The purpose of this review is to disseminate the acquired knowledge and briefly summarize the findings of the REDS-II studies conducted in Brazil as well as to introduce the scope of the REDS-III program that is now in progress and will continue through 2018