HIV-related thrombocytopenic purpura: a study of 24 cases

In this paper we review our experience with HIV-related thrombocytopenic purpura (TP) in 24 patients seen from October, 1985 through April, 1988: the median follow-up was 16 months (range 3-32). All patients belonged to risk groups for AIDS and intravenous drug abusers represented 83% of the entire cohort. The male/female ratio was 4, and most of the patients were Walter Reed stage 3. The mean value of platelets at diagnosis was 33 x 10(9)/liter (range 6-120), and half of the patients had severe thrombocytopenia with hemorrhagic symptoms. Anemia and/or neutropenia were concomitant with TP in 21% and 17% of cases; four cases had pancytopenia. Marrow pictures showed megakaryocytic hyperplasia in 68% of cases; myelodysplasia or hypoplasia were observed in 14% and 18% of patients, respectively; lymphoid aggregates were present in two cases. Antiplatelet antibodies and circulating immune complexes were detected in 40% and 50% of cases, and the mean T4/T8 ratio was 0.9 (range 0.4-1.8). Half of the patients did not require specific therapy due to lack of bleeding; however no spontaneous reversions to normal platelet values occurred. The response to steroids and to immunoglobulins (either high-dose or anti-D) was good but temporary, and required maintenance therapy. The 2-year actuarial risk of evolution into overt AIDS was 30%, with a crude rate of 4 cases over 365 person-months at risk. The events which determined AIDS were opportunistic infections in two cases, Kaposi's sarcoma and malignant lymphoma in the other two. A comparison with the features of idiopathic TP is made and hypotheses regarding the pathogenetic mechanisms are discussed.