Treatment of babesiosis by red blood cell exchange in an HIV-positive, splenectomized patient.

Babesiosis is a malaria-like parasitic disease causing subclinical or mild illness in most cases. Splenectomized patients, however, may experience a more severe course. Although generally responsive to antibiotic therapy, several cases of severe babesiosis refractory to appropriate antibiotic therapy have been reported to respond promptly and dramatically to red blood cell (RBC) exchange transfusion. Although the role of HIV coinfection in babesiosis is uncertain, two previously reported cases raise a concern that it may predispose to a more severe clinical course. We report a third case of severe babesiosis in an HIV-positive splenectomized man, following travel to an endemic area. Antibiotic therapy, though initially effective, ultimately failed to prevent severe disease. RBC exchange transfusion resulted in prompt clinical improvement, which has been sustained during 26 months of follow-up. Although the patient has since developed various sequelae of HIV infection, including disseminated Kaposi's sarcoma, CMV retinitis, and enteritis, there has been no recurrence of observable parasitemia. In severe babesiosis, RBC exchange transfusion, combined with appropriate antibiotic therapy, appears to be a rapidly effective therapeutic modality which can induce sustained remissions.