Neutrophil function in infection-prone children.

Seven variables connected with the function of the neutrophil granulocyte were studied in 24 children who had undue susceptibilities to infections. The phagocytosis rate of IgG-coated latex particles by the patients' neutrophils was significantly reduced compared with an age-matched control group. The chemokinetic effect of patients' sera on normal polymorphonuclear neutrophil leucocytes was reduced too, especially in heated (56 degrees C, 30 min) serum. Spontaneous chemotactic activity in the patients' sera was significantly lower than in sera from healthy adults and from the age-matched control group. A functional index based on the 7 variables of neutrophil function was constructed. The score of the functional index was correlated to the severity of the patients' clinical condition and discriminated well between normal children and those with undue susceptibility to infections.