There is an urgent need to investigate whether or not accumulations of CTL escape mutations at a population level increase the virulence of HIV-1 infection. In the present study, we have examined the impact of HLA class I allele expression on the level of pVL and rate of CD4+ T cell decline in

chronically HIV-1 infected Japanese patients who have distinct class I allele expression profiles compared to Caucasians or Africans, in that: (1) they selleck compound express neither major protective alleles (HLA-B27/B57) nor detrimental alleles (HLA-B*3502/B*3503/B53); and (2) they have a much narrower HLA distribution as represented by around 70% of Japanese people expressing HLA-A24 (18), and thereby

likely facilitate accumulation of CTL escape mutations at the population level. In a cross-sectional analysis, we found no significant associations between the level of pVL and individual HLA PI3K inhibitor class I allele expression in this unique Asian population, including HLA-B51 which ranked as the third most protective allele in Caucasians (7). Further analysis revealed that HLA-B51 has been losing its ability to control viremia in this population as the epidemic matures. However this is not the case for the other alleles, suggesting that unfavorable consequences of the accumulation of CTL escape mutations might be limited to particular HLA class I alleles. Nonetheless, these differences still pose a significant challenge for those designing globally effective HIV vaccines. In the present study, a total of 141 Japanese subjects who had been diagnosed with HIV-1 infection from 1995 to 2007, and had remained untreated, were enrolled. Dimethyl sulfoxide In order to exclude individuals diagnosed during an acute/early phase of infection, only those who were fully Western blot positive were enrolled, while those with a history of being HIV seronegative

within the year prior to their first visit to the clinics were excluded. Written informed consent was obtained from all participants, and the study was approved by the Institutional Review Boards of the Institute of Medical Science, the University of Tokyo (No. 11-2-0329). All the participants were Japanese and all had acquired HIV-1 through sexual intercourse; all but six were men, 96% of whom were MSM. PVL were measured by the Roche HIV Amplicore (Roche Diagnostics, Indianapolis, IN, USA). PVL and CD4+ T cell counts at the first available time points were used for the analyses. The median pVL was 19 000 RNA copies/ml (IQR: 5000–49 000 RNA copies/ml). The median CD4+T cell count was 351/μl (IQR: 273–444/μl) at the corresponding time point for each individual. The rates of decline in CD4+ T cell count (cells/year) were calculated using the values at 6 and 18 months after the first visit to the hospital.