ACQUISITION OF SYNCYTIUM-INDUCING HIV-1 STRAINS DURING THERAPY WITH ZIDOVUDINE ALONE OR COMBINED WITH ALPHA-INTERFERON OR DIDANOSINE

The effect of antiretroviral treatment on HIV-1 phenotype was studied in a group of 83 nucleoside-naive patients. These initially nonsyncyti um-inducing HIV-1 positive patients were followed prospectively for th eir HIV-1 phenotype. Syncytium-inducing variants were detected by cocu ltivation of peripheral blood mononuclear cells with the MT-2 T-cell l ine. Overall, 16 of 83 (19%) patients underwent a shift to syncytium-i nducing phenotype: 11 of 67 during zidovudine treatment, 3 of 10 durin g zidovudine plus alpha interferon treatment, and 2 of 6 under initial zidovudine plus didanosine therapy. The results of this study demonst rate that neither zidovudine therapy alone nor combined with interfero n or didanosine prevents the acquisition of syncytium-inducing strains .