[A population-genetics approach to the problem of nonspecific biological resistance of the human body. III. The ABO and rhesus blood group systems of healthy and sick children and their mothers].

ABO and Rhesus blood types have been specified in 2047 diseased newborns, diseased infants and children who died before the age of one, as well as in their mothers. 527 healthy children and their mothers were investigated as a control group. A significant difference in the ABO phenotype frequencies has been revealed between: i) healthy and dead children, ii) mothers of diseased newborns and mothers of healthy children, iii) dead children and their mothers. The significant increase in the incidence of maternal Rhesus-negative phenotype, as compared with the control group, was shown in the groups of diseased newborns, diseased infants and dead children. In the same groups, mothers differ significantly from their children with respect to the frequency of Rhesus phenotypes. The incidence of Rhesus-incompatible mother-child pairs in the groups of diseased newborns, diseased infants and dead children was shown to be two times higher than the respective frequency in the control group and the expected frequency. A certain increase in the frequency of ABO-incompatible pairs was revealed in the groups of diseased newborns and dead children, but the difference, as compared to the control group, did not prove to be statistically significant. A hypothesis was advanced to the effect that the mother-child incompatibility for Rhesus and ABO antigens may result not only in fetal wastage and haemolytic disease of newborns, but also in the decrease of child's resistance to diseases of different origin.