 caused by abnormalities in the eosinophil cell line; b) Secondary, i.e.caused by non-eosinophil disorders; and c) Idiopathic, cause unknown.The World Health Organization classifies these disorders into a) Myeloid and lymphoid neoplasms with eosinophilia and abnormalities of "PDGFRA, PDGFRB", or "FGFR1" (i.e.