The analysis of eosinophil and lymphocyte phenotype following single dose of high-dose methylprednisolone in two siblings with marked hypereosinophilia

The effect of single high‐dose methylprednisolone (HDMP) on eosinophil and lymphocyte phenotype in two siblings with marked hypereosinophilia was investigated. Since conventional dose steroids failed to produce a haematological and clinical response in case one, both children were given HDMP (20 mg/kg/day). Eosinophils and lymphocytes showed an activated state before treatment, characterized by marked expression of CD11b, CD18, CD45RO on eosinophils and increased HLA‐DR, CD95, CD18, CD38 on lymphocytes. Twenty‐four hours after administration of HDMP a dramatic reduction in peripheral blood eosinophil count was observed in both patients associated with phenotypic changes characterized by decreased expression of CD11b, CD18, CD13 and increased CD95 expression in one. Furthermore, HDMP treatment induced a drop in the expression of CD95 and CD18 on lymphocytes. These changes may suggest a suppressive role for HDMP on eosinophil and lymphocyte activation which may have contributed to the haematological and clinical response.