Increase in plasma interleukin-10 following hydrocortisone injection

In view of the fact that glucocorticoids have an immunosuppressive effect and the fact that interleukin-10 (IL-10) is inhibitory to T helper cell function, we have now investigated the effect of hydrocortisone on plasma IL-10 concentrations. Seven normal subjects were injected with 100 mg hydrocortisone intravenously between 8 and 9:00 a.m. Sequential blood samples were obtained prior to and 1,2,4,8 and 24h after the injection. Plasma IL-10 concentrations increased significantly and consistently following the injection in all subjects. The peak increase of IL-10 occurred at 4h and the restoration to baseline by 8h. The sequential values were (mean±SD): 3.0±1.3 pg/ml at 2h, 9±4.2 pg/ml at 4h, 3.7±1.8 pg/ml at 8h and 3.7±1.4 pg/ml at 24h. The magnitude of increase was 436% of the basal at peak effect. This effect of hydrocortisone (and possibly other glucocorticoids) may contribute to the immunosuppressive effect of this drug. IL-10 may also be potentially useful in the assessment of Cushing's Syndrome as a marker of end organ effect of glucocorticoids.