EFFECT OF MALNUTRITION IN ECUADORIAN CHILDREN ON TITERS OF SERUM ANTIBODIES TO VARIOUS MICROBIAL ANTIGENS

The titers of serum antibodies to natural infection with enteric and r espiratory pathogens, to a food antigen and to tetanus and diphtheria toroid were evaluated by enzyme-linked immunosorbent assay in 1,554 Ec uadorian children younger than 5 years of age, The nutritional status of the children was assessed by anthropometry and measurement of bioch emical status indicators, The children were enrolled in a representati ve national nutrition and health survey, Antibody titers were analyzed as a function of the nutritional status of the children, For 12 of 14 antibody concentrations tested, underweight children showed lower ant ibody titers than did control children, The difference was statistical ly significant for antibody to both T-cell-dependent antigens (tetanus toroid, rotavirus, respiratory syncytial virus) and T-cell-independen t antigens (lipopolysaccharide, polyribosyl-ribitol phosphate, capsula r polysaccharide). When children with a recent episode of diarrhea wer e excluded, many of the differences remained significant, When these c hildren were further classified by age, only difference in titers of a ntibodies to respiratory syncytial virus and tetanus toroid remained s ignificant, No statistically significant difference was detected betwe en underweight and control children with respect to protective antibod y levels to four bacterial antigens, Anemic children showed significan tly lower antibody levels to both T-cell-dependent and T-cell-independ ent antigens than did control children, and a higher proportion of ane mic children had diphtheria antitoxin below a conservatively defined p rotective antibody level, No major differences in antibody titers were seen between children with different retinol and zinc concentrations in serum.