Immunocompetence of children with frequent respiratory infections.

119 children with recurrent respiratory infections were investigated for immunocompetence. They were divided into two groups. The first, group A, comprised children who had had predominantly upper respiratory infections. Group B comprised those who had had repeated pneumonia in addition. The groups were comparable for gender and age (mean 4.2 years). All the children had reduced neutrophil chemotaxis, reduced neutrophil fungicidal capacity, and perhaps reduced T-cell percentages. Group B children had, in addition to the above, decreased neutrophil bactericidal capacity and a more marked depression of neutrophil chemotaxis. In both groups, some children had reduced immunoglobulin concentrations while others had either normal or increased concentrations. Serum complement, neutrophil iodination, and mitogen-induced lymphocyte transformation were comparable with adult controls in both groups.