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 homosexua l men with HIV-associated ITP and less than or equal to 50 x 10(9) platelet s were analyzed after they were placed on HAART. At initial evaluation, 7 p atients were antiretroviral naive, 2 were taking zidovudine alone, and 2 we re receiving combination antiretroviral therapy for known HIV infection. Fo r 6 patients with <30 X 10(9) platelets, prednisone was initially coadminis tered with HAART. The primary outcome measure was the platelet count respon se to HAART, which was measured weekly until counts had normalized on 3 con secutive occasions, then every 3 months while on HAART. Secondary outcome m easures were HIV-viral RNA levels and CD4+ cell counts. Results: One month after the initiation of HAART, 10 evaluable patients had an increase in mea n 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 a nd 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), wi th no thrombocytopenic relapses. The 9 long-term platelet responders have b een 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-lympho cyte cell count. Conclusion: HAART seems to be effective in improving plate let counts in the setting of HIV-associated ITP, enhancing CD4+ cell counts , and reducing HIV viral loads.