Thrombotic microangiopathy in the setting of human immunodeficiency virus infection: High incidence of severe thrombocytopenia

BACKGROUND: Human immunodeficiency virus (HIV) infection increases the risk of thrombotic microangiopathy (TMA), but TMA in the setting of HIV infection is not well characterized. The experience with TMA in the setting of HIV infection at the University of Maryland Medical Center was reviewed. STUDY DESIGN AND METHODS: Patients undergoing therapeutic plasma exchange (TPE) for TMA from January 1, 2000 through December 31, 2012 were reviewed. Those with known HIV-positive and -negative status were compared. RESULTS: Among 102 patients with known HIV status, 28 (27%) were HIV-positive, including 3 with previously undiagnosed HIV. HIV-positive patients had a median viral load of 89 500 copies/mL (range, 0->750 000 copies/mL) and a median CD4 count of 58 cells/µL (range, 2-410 cells/µL). Compared to HIV-negative patients, HIV-positive patients more frequently presented with concurrent infections (60.7% vs. 23.7%; P = .0007), had a trend toward lower median platelet counts (3000/µL vs. 15 000/µL; P = .07) and more frequently had platelet counts less than 10 000/mcL (P = .02). Nevertheless, number of TPE procedures required for remission, remission rate, mortality, and relapse incidence were similar in HIV-positive and HIV-negative patients. CONCLUSIONS: The incidence described herein of HIV infection among TMA patients is the highest reported outside of South Africa. More severe thrombocytopenia in HIV-positive patients may reflect TMA in the setting of preexisting HIV-associated thrombocytopenia. HIV should be considered in patients with TMA, and TMA should be considered in HIV-positive patients with severe thrombocytopenia.