THALIDOMIDE - A NOVEL THERAPY FOR MICROSPORIDIOSIS

Background & Aims: Microsporidiosis is a common cause of chronic diarr hea in human immunodeficiency virus (HIV)-seropositive individuals and often does not respond to treatment, Fecal tumor necrosis factor alph a (TNF-alpha) is elevated in microsporidiosis; therefore, thalidomide, an anti-TNF-alpha agent, was used as therapy, Methods: Eighteen subje cts with chronic diarrhea caused by Enterocytozoon bieneusi that had n ot responded symptomatically to albendazole and 1 untreated subject wi th Encephalitozoon intestinalis received 1 month of thalidomide, 100 m g nocte. Clinical response was assessed by stool frequency and body we ight, histological response by light microscopy with villus height/cry pt depth ratios and electron microscopy, and immunologic response by f ecal TNF-alpha level, Results: Seven subjects with chronic diarrhea du e to E. bieneusi had a complete clinical response, and 3 had a partial response to thalidomide. There was a significant decrease in stool fr equency from 5.3 to 3.1 per day (P = 0.001), and weight increased sign ificantly by 1.2 kg (P < 0.02), Thalidomide significantly increased th e villus height/crypt depth ratio (1.95 to 2.07; P = 0.045) and number of abnormal forms of microsporidia (P < 0.01), Fecal TNF-alpha level nonsignificantly decreased from 17.9 to 8.9 U/mL. There was apparent d isruption of all stages of the life cycle of E. intestinalis. Conclusi ons: Thalidomide may be an effective therapy for diarrhea and weight l oss from E. bieneusi.