Serum concentrations of IL-5, GM-CSF, and IL-3 and the production by lymphocytes in various eosinophilia.

The concentrations of interleukin-5 (IL-5), granulocyte-macrophage colony-stimulating factor GM-CSF, and interleukin-3 (IL-3) in serum and in IL-2-stimulated lymphocyte culture medium (L-IL2-CM) prepared from patients with reactive eosinophilia were measured by enzyme-linked immunosorbent assay (ELISA). Serum IL-5 levels were increased in 16 out of 42 cases. GM-CSF and IL-3 were below the detectable levels in all sera examined. The concentrations of IL-5 and GM-CSF in L-IL2-CM were increased in 10 out of 29 patients. IL-3 was below the detectable levels in all L-IL2-CM.