[Eosinophil colony stimulating factor (Eo-CSF) activity and soluble interleukin-2 receptor (sIL-2R) in patients with...

To explore the pathophysiology of patients with reactive eosinophilia from unknown cause, we measured the eosinophil colony stimulating factor (Eo-CSF) activity in the interleukin-2 (IL-2) stimulated lymphocyte conditioned medium (CM) prepared from 22 patients with reactive eosinophilia. Eo-CSF activity, the levels of interleukin-5 (IL-5) and granulocyte-macrophage colony stimulating factor (GM-CSF) were increased in the CM from patients with high IgE levels. Hydrocortisone decreased the level of Elo-CSF in the CM. Elevated serum levels of soluble IL-2 receptor (sIL-2R) were presented in 13 out of 15 patients with eosinophilia. The sIL-2R levels in patients with marked eosinophilia (>3000/mu l) were higher than those in patients with mild eosinophilia (< or = 3000/mu l). High sIL-2R levels were noted in T cell CM from 3 out of 15 patients and in eosinophil CM from 1 out of 4 patients. These data suggested that lymphocyte from eosinophilic patients with elevated IgE produce Eo-CSF, IL-5 and GM-CSF by IL-2 stimulation. Eo-CSF production is inhibited by hydrocortisone. SIL-2R is released from lymphocyte and in some case may be released from eosinophils.