Some observations on the properties of precipitating antibody to Staphylococcus aureus in children with kwashiorkor.

Using three relatively sensitive immunochemical assay procedures, we were unable to detect either precipitating or hemagglutinating antibodies to food antigens in sera from normal and kwashiorkor Nigerian children. However, antibody to Staphylococcus aureus, a common pathogenic bacteria in the tropics, could be detected in the sera of 28 of 30 control children but in only 7 of 30 kwashiorkor cases, suggesting that there is an impairment to specific antibody production in children with malnutrition. Comparative biologic and physicochemical studies carried out on precipitating antibodies to S. aureus isolated from normal and kwashiorkor subjects showed that the antibody from malnourished individuals fixed complement less readily and was deficient in some essential amino acids. These defects might in part explain why children with protein-energy malnutrition are more susceptible to infection in spite of the fact that they have normal serum immunoglobulin concentrations.