Defects in polymorphonuclear neutrophil function and susceptibility to infection in children.

Polymorphonuclear neutrophil (PMN) migration, phagocytosis, chemiluminescence production and chemotactic and chemokinetic activities in serum were investigated in 38 infection-prone children, aged 1 month to 15 years, and in healthy controls. The patients were grouped according to the clinical pattern, that is, into children with mainly upper respiratory tract infections, with frequent middle ear infections, with lower respiratory tract infections and with 'multifocal' infections occasionally accompanied by complications, and according to the severity of the infections. Forty-two defects were found in 28 of the 38 patients examined. Good accordance was found between clinical symptoms and abnormal PMN function. Several of the observed abnormalities are most likely inherited and primary causes of the increased susceptibility, but some of them probably occur as a consequence of the infections. The results indicate that defects in oxidative PMN metabolism and defects in Fc-receptor-dependent phagocytosis are major determinants of susceptibility to infection and that such defects seem to be especially common in patients with severe 'multifocal' infections.