Zidovudine treatment is not associated with HTLV-1 reverse transcriptase gene mutations in HTLV-I/HIV-1 co-infected patients.

Zidovudine treatment of human immunodeficiency virus (HIV) infection induces drug-resistant viral strains harbouring specific amino acid substitutions in the reverse transcriptase (RT). To investigate whether this phenomenon could be observed in the case of human T lymphotropic virus type I (HTLV-I) infection, we analysed the HTLV-I RT proviral gene sequence in five HTLV-I/HIV-1 co-infected patients treated with zidovudine for HIV-1 infection and in one untreated co-infected subject. In the 816 bp of HTLV-I pol gene sequence determined, no particular nucleotide mutation associated with zidovudine therapy could be identified in the treated subjects. Moreover, the dominant HTLV-1 deduced amino acid sequences determined in treated subjects were identical to that from the untreated subject. Our data show that in the co-infected patients already presenting well-defined mutations associated with zidovudine resistance in HIV-1, no mutations were observed in a part of the pol gene coding for the RT activity of HTLV-I.