Researchers at the National Cancer Institute and the National Institutes of Health are warning doctors to avoid giving the anticancer drug actinomycin D (ActD) to their HIV-positive patients because new research shows the drug speeds up HIV replication in the body, AIDSWeekly reports. ActD had been reported to be a potential inhibitor of human immunodeficiency virus type 1 (HIV-1) replication due to its ability to inhibit reverse transcription, said researcher Tomozumi Imamichi. However, research shows ActD actually enhances HIV replication in MT-2 T-lymphoma cells, boosting viral replication 10-fold or more. MT-2 cells treated with ActD also showed strong resistance to the anti-HIV drugs AZT and d4T. "These results suggest that administration of combination drugs to HIV-1-infected patients may induce resistance to antiretroviral compounds via a modification of cellular factors," Imamichi concluded.