Endotoxin-induced colony stimulating activity in normal and myeloid leukaemic subjects.

Low doses of endotoxin were administered to normal and acute anc chronic myeloid leukaemic subjects. Temperature, leucocyte count, blood colony stimulating activity and the number of circulating colony forming units were monitored. All subjects acquired fever while the leucocyte count remained unaltered. Blood CSA rose sharply in 6 normal individuals, but failed to increase in 4 acute leukaemic patients and in 2 patients with CML in blast crisis. 2 patients with CML in the chronic stage increased their blood CSA comparable to normal individuals. The number of circulating colony forming units rose following endotoxin with a peak at 30 min and declined subsequently. 4 patients with acute leukaemia showed no increase of circulating colony formers.