Neutrophil Releasing Activity in Plasma of Normal Human Subjects Injected with Endotoxin ∗

Abstract

Summary

Normal human subjects were injected with endotoxin and their plasma was harvested at various times thereafter. This plasma was later infused into the same subject, to determine if neutrophilia inducing activity was demonstrable in such plasma.

Infusion of normal control plasma induced no significant change in total neutrophil concentration and nonsegmented neutrophils tended to decline after such infusions.

Plasma collected after injection of endotoxin did not induce a significant change in blood neutrophils as compared to control plasma if obtained at a time when no significant increase in the rate of release had developed in the donor. Postendotoxin plasma, collected when the donor was releasing neutrophils at an abnormally rapid rate, induced a significant increase in both total and nonsegmented neutrophils.

Infusion of active postendotoxin plasma induced a more rapid onset of neutrophilia than did endotoxin injection. This observation and the inactivity of certain plasmas which were collected after the same dose of endotoxin yielding active plasma suggested that the activity of postendotoxin plasma was not representative of persistence of the injected endotoxin.

This study, in conjunction with similar studies in other species, suggests that the rate of release of neutrophils from the marrow to the blood may be controlled by a humoral factor.