Zidovudine (AZT) reduces virus titer, retards immune dysfunction, and prolongs survival in the LP-BM5 murine induced immunodeficiency model

Using the murine LP-BM5 retrovirus-induced immunodeficiency model, the therapeutic value of zidovudine (AZT) was analyzed. Continuous low dose (60 mg/kg per day) oral AZT administration for 6 weeks increased survival time by 5-6 weeks. Decreasing the duration of therapy to 3 weeks decreased the mean survival time. Extending the therapy from 6 to 14 weeks increased the median survival time (8 weeks). This dose was nontoxic and reduced virus titers, splenomegaly, and lymphadenopathy. AZT also retarded the immune dysfunction syndrome characteristic of this model. Hypergammaglobulinemia was reduced by AZT and was also a marker for disease progression. AZT reduced hyperproliferation of large blast cells and delayed the loss of splenic B cells.