Experimental murine schistosomiasis mansoni: inhibition of neutrophil granulocyte inflammatory reaction.

1. The mobilization of neutrophils into the peritoneal cavity following stimulation with sterile mineral oil was studied in normal and schistosome-infected mice. This response was correlated with changes in blood neutrophil counts and with the production and release of medullar granulocytes. 2. The peritoneal neutrophil inflammatory reaction was considerably reduced in schistosome-infected mice. The medullar pool of mature neutrophils was totally depleted, in spite of an increased number of immature neutrophil precursors. 3. We conclude that the decreased inflammatory response of neutrophils during schistosomiasis is due to the delay of their maturation in the bone marrow. A similar delay has been observed in schistosomal patients. A causal relationship between delay of neutrophil maturation and sensitivity of schistosomal patients to chronic microbial infections is suggested by these data.