ADMINISTRATION OF G-CSF TO HEALTHY-SUBJECTS - THE EFFECTS ON EOSINOPHIL COUNTS AND MOBILIZATION OF EOSINOPHIL GRANULE PROTEINS

Any influence of G-CSF on eosinophils is mostly negative, although rep orts which have studied this relationship are few with varied results. The aim of this study was to investigate the influence of G-CSF admin istration to healthy subjects on eosinophils in peripheral blood. Bloo d eosinophil counts, serum levels of eosinophil cationic protein (ECP) , eosinophil peroxidase (EPO) and eosinophil protein X (EPX), as well as cell morphology were studied, 14 healthy volunteers received 7.5 mu g (n = 8) or 10 mu g/kg body weight (n = 6) G-CSF daily for six conse cutive days, ECP and EPX were assessed by specific RIAs and EPO by a s pecific FEIA. Cell morphology was examined by electron microscopy. Dur ing G-CSF administration, eosinophil counts increased from 0.22 +/- 0. 04 x 10(9)/l to 0.61 +/- 0.098 x 10(9)/l (P = 0.001), serum ECP from 1 2.39 +/- 2.45 mu g/l to 61.82 +/- 7.38 mu g/l (P = 0.0014), serum EPX from 28.05 +/- 4.54 mu g/l to 87.86 +/- 9.84 mu g/l (P = 0.002) and se rum EPO from 8.89 +/- 2.2 mu g/l to 19.98 +/- 5.1 mu g/l (P = 0.003). All variables returned gradually to initial values after discontinuati on of G-CSF. Distinct changes in the morphology of secondary granules were observed 24 h after G-CSF administration. The granules became irr egular and their matrix less electron dense. We conclude that administ ration of G-CSF to healthy humans increases the number of circulating eosinophils and affects the mobilization of eosinophil granule protein s.