Natural polymorphisms of protease in protease inhibitor-naive HIV-1 infected patients in Korea: a novel L63M in subtype B.

To establish a baseline for monitoring resistance mutation to protease inhibitors (PI), we determined protease(PR) sequences in peripheral blood mononuclear cells obtained from 43 PI-naive Korean HIV-1 infected patients. Interestingly, phylogenetic analysis revealed that 41 of the sequences belonged to subtype B, one belonged to subtype A, and one was unique, not clustering with any subtype. Thirty-one (76%) of the 41 sub-type B sequences formed a subclade within subtype B, a so-called "Korean B cluster." Polymorphisms were observed at 34 (34.3%) of the PR codons. One patient (2.3%) harbored a primary resistance-conferring mutation, L90M along with L63P and A71V, and all 43 strains showed some secondary associated with drug resistance. The percentage of patients with 7, 5, 4, 3, 2, and 1, resistance mutations were 2%, 2%, 14%, 23%,37%, and 9%, respectively. A novel polymorphism in subtype B, L63M was detected in two patients. Another patient showed a gross deletion (257 bp) after codon 91. The average genetic distance of the 41 subtype B sequences to the HXB2 sequence was 3.0% (range, 1.0-5.1%). Six hemophiliacs were infected with a domestic strain of HIV-1 subtype B, while the other two hemophiliacs were infected with nondomestic subtype B and had lived outside Korea. Although this is the first report on the molecular nature of PR in Korea, there is also a need to establish baselines for nonsubtype B HIV-1.