Initial observations on the efficacy of highly active antiretroviral therapy in the treatment of HIV-associated autoimmune thrombocytopenia

Background: Immune thrombocytopenic purpura (ITP) occurs in as many as 40% of patients infected with the human immunodeficiency virus (HIV). We sought to evaluate the effect of highly active antiretroviral therapy (HAART) on platelet counts in such patients. Methods: Data collected from 11 homosexual men with HIV-associated ITP and less than or equal to 50 x 10(9) platelets were analyzed after they were placed on HAART. At initial evaluation, 7 patients were antiretroviral naive, 2 were taking zidovudine alone, and 2 were receiving combination antiretroviral therapy for known HIV infection. For 6 patients with <30 X 10(9) platelets, prednisone was initially coadministered with HAART. The primary outcome measure was the platelet count response to HAART, which was measured weekly until counts had normalized on 3 consecutive occasions, then every 3 months while on HAART. Secondary outcome measures were HIV-viral RNA levels and CD4+ cell counts. Results: One month after the initiation of HAART, 10 evaluable patients had an increase in mean platelet count. This improvement was sustained at 6 and 12 months' follow-up for 9 of 10 evaluable patients. Increases in mean platelet count at 6 and 12 months of the 9 responders were statistically significant. The range of follow-up in the 9 responders is 27 to 46 months (median, 30 months), with no thrombocytopenic relapses. The 9 long-term platelet responders have been maintained on HAART and at 12 months had a mean reduction of > 1.5 log(10) in HIV viral RNA serum levels and a marked improvement in CD4+ T-lymphocyte cell count. Conclusion: HAART seems to be effective in improving platelet counts in the setting of HIV-associated ITP, enhancing CD4+ cell counts, and reducing HIV viral loads.