Polymorphism of human blood groups and incidence of influenza A/Hong Kong (H3N2).

During three epidemics of influenza A/Hong Kong (H3N2) and experimentally in vaccines, the relation between influenza infection and ABo, Rh and MN blood groups was studied. Examinations of 2760 patients with laboratory-confirmed diagnosis of influenza and 749 persons vaccinated with live influenza vaccine showed that individuals of blood groups O and B were susceptible to influenza 1.67 and 1.20 times more, respectively, than individuals of blood group A. The difference in incidence was most manifested in first attacks and decreased in subsequent epidemics. The increased incidence in individuals of blood groups O and B as compared to those of blood group A was not associated with factors of specific (antibody) and nonspecific (interferon) resistance to influenza but was related to a greater capacity of leukocytes from these individuals to adsorb the virus. No relation between blood groups Ph and MN and incidence of influenza A/Hong Kong (H3N2) was established.

The mechanism of group differences in the character of the vaccinal process in immunization against natural smallpox.

The effect of antigenic polymorphism of the ABO-system blood groups on the character of the vaccinal process after immunization against natural smallpox was investigated. The increased susceptibility of persons possessing A antigen to the harmful effect of smallpox vaccine virus is due to hereditary rather than to acquired factors. The leukocytes of peripheral blood of these persons showed a poorer binding capacity with respect to the smallpoxvaccine virus; they also exhibited a high rate of chromosomal aberration after vaccination, resulting to some extent from increased proliferative ability of the cells.