Migration of eosinophil (Eo) into tissues is a hallmark of chronic eosinophilic leukaemia (CEL), but the exact mechanism involved in cell migration is unknown. We report on a patient with CEL who presented high expressions of VLA-4, LFA-1 and Mac-1 integrins on the Eo surface, increased chemotaxis of Eo to eotaxin, decreased chemotaxis of Eo after inhibition of the cyclic guanosine monophosphate (cGMP), and a high level of intracellular cGMP. These findings suggest that an upregulation of expression of these integrins on Eo surface and a high intracellular level of cGMP may be involved in the increased Eo migration observed in our CEL patient. However, the definitive roles of these molecules in the proliferation and migration of Eo in CEL disease require wider confirmation by analysis of additional patients with the disease.31695-7