RECOMBINANT ALPHA-INTERFERON 2B IN THE TREATMENT OF HIV-RELATED THROMBOCYTOPENIA

Objective: To assess the efficacy and the mechanism of action of alpha -interferon (alpha-IFN) in the treatment of HIV-related thrombocytopen ia. Methods: Thirteen HIV-positive subjects [nine men and four women w ith severe thrombocytopenia (platelets, less-than-or-equal-to 30 x 10( 9)/l)] were treated with alpha-IFN2b alone at a dose of 3 x 10(6) U th ree times a week for 5 weeks. Haematological parameters, platelet kine tic and bone-marrow myeloid progenitor cultures [megakaryocyte colony- forming units (CFU-MK); granulocyte macrophage CFU (CFU-GM) and erythr oid burst-forming units (BFU-E)] were evaluated before and after treat ment in responsive subjects. Results: Seven out of 13 subjects showed a partial response (platelets, 50-149 x 10(9)/l) after alpha-IFN2b the rapy. Platelet survival as evaluated by In-111-oxine significantly inc reased, while platelet turnover showed a slight but not statistically significant increase after treatment. The growth of bone-marrow myeloi d progenitor cells decreased after alpha-IFN2b therapy, again without statistical significance. Conclusion: alpha-IFN2b may increase the pla telet count in HIV-positive subjects with severe symptomatic thrombocy topenia by prolonging platelet survival. The immunomodulatory and anti viral action of this drug may be responsible for prolonged platelet su rvival.