Chromosome and cell culture studies in eosinophilic leukaemia.

A cytogenetic analysis was carried out on bone marrow cells from 11 patients who presented with hypereosinophilia and the clinical features of the idiopathic hypereosinophilic syndrome. One of these patients was found to have trisomy 8 affecting the myeloid series, including eosinophils. In this patient, marrow eosinophils also showed asynchrony of nuclear-cytoplasmic maturation, and there were increased numbers of myeloid progenitor cells in the blood. Six months later, blast cell transformation occurred, and he died soon afterwards. These findings show that abnormalities in the karyotype of bone marrow cells and culture of blood progenitor cells may help to identity eosinophilic leukaemia among patients who present with features of the idiopathic hypereosinophilic syndrome.