Successful treatment of hypereosinophilic syndrome with cyclosporine.

A 63-year-old man with lymphocytic variant hypereosinophilic syndrome (HES) characterized by a T-cell receptor gene rearrangement was treated with cyclosporine with marked improvement in his symptoms and reduction in his total eosinophil count. We present this as the first report to demonstrate cyclosporine as an effective treatment of HES in an adult.