SERUM CONCENTRATIONS OF GRANULOCYTE-COLONY-STIMULATING FACTOR (G-CSF)DETERMINED BY A HIGHLY-SENSITIVE CHEMILUMINESCENT IMMUNOASSAY DURING THE CLINICAL COURSE OF SUBACUTE THYROIDITIS

Granulocyte colony-stimulating factor (G-CSF) concentrations in serum were determined for the first time by a newly developed and highly sen sitive chemiluminescent immunoassay (the limitation of detection, 0.5 pg/ml) in ten patients with subacute thyroiditis, during treatment wit h glucocorticoid or indomethacin. Before therapy, circulating neurophi l counts significantly increased to 5.15 +/- 2.07 x 10(3)/mu l compare d with the convalescent phase (2.94 +/- 1.07 x 10(3)/mu l), and the da ta were correlated with individual serum G-CSF levels (r=0.854, P<0.01 ). Serum concentrations of interleukin-3 (IL-3) and granulocyte-macrop hage colony-stimulating factor (GM-CSF) were less than the detectable threshold of ELISA. During two weeks of glucocorticoid therapy, althou gh the circulating neutrophil counts increased from 5.15 +/- 2.46 x 10 (3)/mu l to 7.73 +/- 1.64 x 10(3)/mu l (P<0.01), serum G-CSF levels we re depressed from 25.1 +/- 15.3 pg/ml to 13.8 +/- 13.9 pg/ml (P<0.01). These data indicate that G-CSF is one of the mediators of the increas e of neutrophils in subacute thyroiditis, while it does not contribute to steroid-induced neutrophilia.