Coexistence of the K65R/L74V and/or K65R/T215Y mutations on the same HIV-1 genome.

Objective: To determine to which extent the mutations K65R, L74V/I and T215Y/F are linked to the same HIV-1 genome.

Methods: Retrospective analysis of the Marseille database (8866 sequences from 3720 patients). The HIV-1 pol gene from four patients' viruses harbouring the double mutant (pure species or genotypic mixtures) was amplified, cloned and sequenced.

Results: The four patients had a mean viral load of 5.6 log(10)copies/ml. Analysis of 73 clones (patient 1: 12 clones; patient 2: 27 clones; patient 3: 13 clones; patient 4: 21 clones) showed that 29 clones harboured K65R and L74V/I mutations. Twenty-three per cent of clones from the two bulk sequences harbouring K65K/R and T215T/Y genotypic mixtures contained K65R and T215Y on the same viral genome.

Conclusions: The co-linearity of 65R and 74V or 65R and 215Y amino-acids on the same genome is rare. A high viral load (6.19 log(10)) associated with the coexistence of 65R and 74V on the same HIV-1 genome suggests possible compensatory mechanisms.