[Correlations of the antigenic specificity of human blood with the levels of antihemagglutinins to influenza viruses].

The results of the observations show that after active circulation of influenza A (H1N1), A (H3N2), and B viruses the degree of immune response (a rise in antihemagglutinin titres to the causative agent of an epidemic) differed significantly in subjects with different blood groups of the ABO(H) system. After active circulation of influenza A(H1N1) and A(H3N2) viruses, rises in the antibody titres to the etiological factor of the epidemic was more marked in subjects with blood groups O and A than in those with blood group B. After an influenza A(H3N2) epidemic a rise in the titres to this virus in subjects with blood group B occurred a season later and did not reach those high levels observed in subjects with blood groups O and A. A reverse picture was observed during increasing morbidity and epidemic of influenza B virus. A rise in the antibody titres to this virus in subjects with blood group B significantly different from that among subjects with the other two blood groups occurred earlier, in the pre-epidemic season (the spring of 1980) and persisted till the end of the epidemic season. This time difference in the onset of the antibody titre rises appears to indicate a higher genetic sensitivity of subjects with blood group O followed by blood group A to influenza A viruses and, first of all, their increased sensitivity to A(H3N2) virus, as well as higher susceptibility to influenza B virus in subjects with blood group B.