[Antigenic similarity of microorganisms to human group-specific blood factors and the immune response of persons with various ABO classifications].

The isohemagglutination test with the introduction of the heat-stable fraction of microbial broth culture into the reacting system was used as a model of the antigen-antibody interaction. In the "A-anti-A" system the inhibition of isohemagglutination in the presence of staphylococcal allergen was observed. This inhibition was caused by the binding of the allergen with anti-A-antibodies, which was indicative of the antigenic similarity between staphylococcus and group-specific factor A. The influence of the similarity thus established on immune response was studied by the determination of antitoxic titers in 292 donors immunized with staphylococcal toxoid and in 86 patients with chronic hematogenic fistulous osteomyelitis with due regard of the ABO phenotype of the examinees. Subjects with group A(II) blood were found to have lesser antibody titers than those with blood of other groups and to be predisposed to the progressive course of staphylococcus-induced diseases.