The evaluation of delayed-type hypersensitivity responsiveness and nutritional status as predictors of gastro-intestinal and acute respiratory infection: a prospective field study among traditional nomadic Kenyan children.

A 10-month prospective study of children from a nomadic pastoralist community in northwest Kenya was conducted to examine the relationship between nutritional status, cell-mediated immunity (CMI), and morbidity due to gastroenteritis and acute respiratory infection (ARI). In children ages 6 months to 10 years, nutritional status and cellular immunocompetence, determined by delayed-type hypersensitivity (DTH), were related to individual attack rates of diarrhoea and ARI over two 5-month observation periods, one each in the wet and dry season. While no association was found between premorbid nutritional status and gastroenteritis, DTH responsiveness was a significant predictor of diarrhoeal disease, with anergic children experiencing, on average, 20 per cent higher attack rates than immunocompetent children. When examined separately, both nutritional status and DTH responsiveness were significant predictors of individual attack rates of ARI in the wet season. However, when the effects of nutritional and immunological status were simultaneously tested, only DTH responsiveness was significant. Anergic children experienced 34 per cent excess ARI, compared to immunocompetent children. These results indicate that cellular immunocompetence is a sensitive predictor of gastrointestinal and respiratory infection, and that the effect of nutritional status on the occurrence of ARI may be mediated by cellular immune function.