The Higher Frequency of Blood Group B in a Brazilian Population with HIV Infection.

OBJECTIVE: To analyze the frequency of and odds for and against HIV infection based on ABO blood type in a large sample of blood donors. BACKGROUND: Coevolution between pathogens and hosts may explain the ABO system of polymorphisms. HIV-infected cells add ABO(H) blood group antigens to the viral envelope. Naturally occurring antibodies against ABO(H) antigens that are present in normal human sera are able to neutralize ABO-expressing HIV in vitro. Blood donors are ideal for studying blood groups and HIV infection in vivo because all donors are routinely typed and tested. METHODS: All blood donors who donated blood between 1994 and 2010 were tested for HIV (ELISA antibody tests and Western blot test or immunofluorescence testing) and were ABO typed (direct and reverse grouping tests). HIV infection based on the ABO blood group was analyzed using the chi-square test and game theory. RESULTS: The total number of examined blood donors during this period was 271,410, of whom 389 were infected with HIV. B-group donors were more infected than non-B donors (p= 0.006). CONCLUSIONS: A more restricted antigen recognition capacity of anti-Galα1-3Gal in blood groups AB and B and a weaker antigen-binding capacity of anti-A antibodies may contribute to a higher frequency of HIV infection in blood group B.