EOSINOPHILIA ASSOCIATED WITH ADULT T-CELL LEUKEMIA - ROLE OF INTERLEUKIN-5 AND GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR

To clarify the mechanism of eosinophilia in adult T-cell leukemia (ATL ), we studied three ATL patients having marked eosinophilia, Eosinophi l-predominant colony-stimulating activity was detected in the serum of one patient and in the conditioned media (CM) from cultured ATL cells from two patients. Soluble interleukin 5 (IL-5), but no interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), was detected in sera from all patients. On the other hand, Gan-CSF wa s produced in vitro by ATL cells from all cases, whereas detectable IL -3 and IL-5 was produced by cells from only one, suggesting that in th e other two cases, the serum IL-5 was produced by the normal reacting lymphocytes. The fact that no patient showed marked neutrophilia suppo rts the possibility that IL-5 may have a leading role in the developme nt of eosinophilia, with GM-CSF produced by ATL cells playing a comple mentary role. (C) 1998 Wiley-Liss, Inc.