Alemtuzumab therapy for refractory idiopathic hypereosinophilic syndrome with abnormal T cells: a case report

A diagnosis of idiopathic hypereosinophilic syndrome was made in a 68-year-old woman in 2002. She was treated with hydroxycarbamide, interferon-a and imatinib (400 mg/d) without evidence of response. In November 2003 she was admitted to our department with anaemia, fever and several painful pruritic skin lesions (top). Immunophenotypic analysis of circulating lymphocytes showed an abnormal CD4 subset characterized by absent surface expression of the CD3 antigen (abnormal T cells have a CD3CD4 CD8 phenotype). Serum interleukin-5 (IL-5) concentration was 280 pg/mol (normal 10 pg/mol). Twodimensional Doppler echocardiography showed endocardial thickening; the left ventricular ejection fraction (LVEF) was 48%. A skin biopsy demonstrated a dermal infiltrate consisting primarily of eosinophils (bottom left). A diagnostic work-up including radiological evaluation failed to reveal an overt lymphoproliferative disorder. As a consequence of the previous demonstration that CD52 is expressed on human eosinophils, the patient was administered subcutaneous alemtuzumab in increasing doses of up to 30 mg weekly. Once commenced on alemtuzumab, her pyrexia settled and the cutaneous lesions started to resolve (bottom right), the LVEF improved to 61% and serum IL-5 concentration fell to 9 pg/mol. Currently, 6 months after the revised diagnosis, the patient is well with an eosinophil count of 0.3 · 10/l on alemtuzumab (30 mg) every 3 weeks.