Characterization of integrase region polymorphisms in HIV type 1 CRF06_cpx viruses in treatment-naive patients in Estonia.

Natural polymorphisms of HIV-1, often associated with drug resistance, are widely described in protease and reverse transcriptase regions but data on their presence in the integrase region, especially in non-B subtypes, are still very limited. We aimed to characterize naturally occurring polymorphisms in the integrase region in 104 treatment-naive and 10 treatment-experienced patients infected predominantly with HIV-1 CRF06_cpx and its recombinant with subtype A1 and/or CRF03_AB viruses. No primary drug resistance mutations against integrase inhibitors were found, but resistance-associated polymorphisms such as V72I, L74I, V201I, and T206S were seen in more than 90% of viruses. Substitutions E157Q and E157K, associated with raltegravir resistance, were found in only two CRF06_cpx strains. We conclude that similar to other HIV-1 non-B subtypes, the CRF06_cpx and its recombinants with subtype A1 and CRF03_AB are rich in integrase region natural polymorphisms, which may impact the development of resistance against integrase inhibitors.