Response of AIDS-related thrombocytopenia to intravenous and oral azidothymidine (3'-azido-3'-deoxythymidine)

A patient with AIDS-related thrombocytopenia (ART) was treated with the new anti-retroviral agent azidothymidine (AZT, Retrovir, zidovudine) by the intravenous and oral routes for a period of 20 weeks. After a 6 week period of initial treatment, the platelet count rose from 38,000 to 140,000/mm3. AZT was intentionally discontinued for three weeks over which the platelet count declined to 70,000/mm3. After reinstitution of AZT, the platelet count rose once again and remained near normal levels for over one year. We conclude that AZT may have efficacy against the thrombocytopenia observed in some patients infected with human immunodeficiency virus (HIV). The pathogenesis of ART and the mechanisms of action of AZT in this condition remain unknown.