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 sensitive chemiluminescent immunoassay (the limitation of detection, 0.5 pg/ml) in ten patients with subacute thyroiditis, during treatment with glucocorticoid or indomethacin. Before therapy, circulating neurophil counts significantly increased to 5.15 +/- 2.07 x 10(3)/microliters compared with the convalescent phase (2.94 +/- 1.07 x 10(3)/microliters), and the data were correlated with individual serum G-CSF levels (r = 0.854, P < 0.01). Serum concentrations of interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were less than the detectable threshold of ELISA. During two weeks of glucocorticoid therapy, although the circulating neutrophil counts increased from 5.15 +/- 2.46 x 10(3)/microliters to 7.73 +/- 1.64 x 10(3)/microliters (P < 0.01), serum G-CSF levels were 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 increase of neutrophils in subacute thyroiditis, while it does not contribute to steroid-induced neutrophilia.