Interleukin 2 stimulates the T‐cells from patients with eosinophilia to produce CFU‐Eo growth stimulating factor

Abstract
To explore the mechanism of eosinophilopoiesis in patients with reactive eosinophilia, we studied the effect of interleukin 2 (IL-2) on the production of CSFs, especially CFU-eosinophil growth stimulating factor (CFU-Eo GSF) from T-lymphocytes in patients with reactive eosinophilia. Conditioned media (CM) prepared from patients’E rosette forming cells (ERFC) with or without IL-2 was assayed for CFU-Eo, CFU-monocyte, macrophage (CFU-M) and CFU-neutrophil (CFU-N) GSF. The addition of IL-2 to the ERFC significantly stimulated the production of CFU-Eo and CFU-M GSF while only CFU-M GSF increased in normals. Serial testing of the CFU-Eo GSF in ERFC-CM demonstrated that the ability of ERFC to produce CFU-Eo GSF with IL-2 stimulation was retained even when the eosinophilia had disappeared. These results suggest that CFU-Eo GSF is produced from T-cells with IL-2 stimulation and that the T-cells from patients produce CFU-Eo GSF with IL-2 stimulation after the disappearance of eosinophilia.