Production of transforming growth factor alpha by normal human blood eosinophils

Transforming growth factor alpha (TGF-α) is a pleiotropic factor mediating numerous cellular responses in normal and transformed cells. This includes differentiation, proliferation, migration, and formation of extracellular matrix. TGF-α has been demonstrated in circulating eosinophils from the idiopathic hypereosinophilic syndrome and in differentiating promyelocytic leukemia cells in vitro. Whether TGF-α production also occurs in normal human blood cells is not known. Northern blot analysis showed that normal human white blood cells consistently expressed the TGF-α gene in 47 out of 47 donors. Cell preparations enriched in mononucleated cells, and devoid of granulocytes, showed no TGF-α mRNA