Can a K103N HIV strain stably overcome the wild type in the absence of non-nucleoside reverse transcriptase inhibitor selective pressure?

The impact of drug resistance mutations on viral fitness is one of the main issues being investigated in HIV therapy. Some, such as M184V, seem to reduce the replicative capacity of HIV, whereas others, such as thymidine analogue-related mutations, seem to potentiate virulence, and persist in the blood for years after the removal of selective pressure. We report a case of an HIV-infected patient whose prevalent viral population continued to carry the K103N mutation for more than 7 years after a 2-year treatment with zidovudine and lamivudine plus loviride despite subsequent changes in therapy with the absolute exclusion of non-nucleoside reverse transcriptase inhibitors (NNRTI).