A 55-year-old woman with human T-cell lymphotropic virus type-1 (HTLV-1)-associated adult T-cell leukemia (ATL) and a history of previously treated Strongyloides stercoralis infection received anti-CD52 monoclonal antibody therapy with alemtuzumab on a clinical trial. After an initial response, she developed ocular involvement by ATL. Alemtuzumab was stopped and high-dose corticosteroid therapy was started to palliate her ocular symptoms. Ten days later, the patient developed diarrhea, vomiting, fever, cough, skin rash, and a deteriorating mental status. She was diagnosed with disseminated S. stercoralis. Corticosteroids were discontinued and the patient received anthelmintic therapy with ivermectin and albendazole with complete clinical recovery. Copyright