[Analysis of HLA-B locus gene polymorphism in Sichuan Yi ethnic group and Xinjiang Uygur ethnic group].

The polymorphism of HLA-B alleles in Sichuan Yi and Xinjiang Uygur population was investigated using the PCR-SSP method. Twenty one alleles were detected in HLA-B loci in 106 Sichuan unrelated Yi healthy subjects. Of them, B*40, B*15 and B*51 were the most common alleles with an allele frequency of 0.1981, 0.1368, 0.1274, respectively; while B*47, B*44, B*18, B*57 and B*78 were the rare alleles with an allele frequency of 0.0189, 0.0142, 0.0094, 0.0047 and 0.0047, respectively. The distribution of HLA-B allele frequencies in Sichuan Yis was between Southern Han and Northern Han. In 110 Xinjiang unrelated healthy Uygur subjects, 27 alleles were detected in HLA-B loci. Of them, B*35 and B*51 were the most common alleles with an allele frequency of 0.1136 and 0.1136, respectively; while B*41, B*56 and B*78 were the rare alleles with a frequency of 0.0045, 0.0045 and 0.0091, respectively. Frequencies of "Caucasoid origin" HLA alleles such as B*08, B*35 and B*50 in Xinjiang Uygurs were higher than other ethnic groups in China. The result of chi2 tests showed that the distributions of HLA-B alleles in Yi and Uygur ethnic groups were in Hardy-Weinberg equilibrium. Heterozygosity (H), discrimination power (DP) and probability of paternity exclusion (EP) of HLA-B locus from Sichuan Yi ethnic group were computed to be 0.8977, 0.9661 and 0.8009; and those from Xinjiang Uygur ethnic group were 0.9372, 0.9857 and 0.8732. The data obtained in this study on the distributions of HLA-B alleles in the Sichuan Yi and Xinjiang Uygur population provide important group genetics information for forensic and paternity tests to estimate the frequency of a DNA profile in these two populations, and can be used in transplant matching, anthropological and disease association studies.

Association of HLA-B alleles with human immunodeficiency virus type 1 infection in the Yi ethnic group in Sichuan province.

OBJECTIVE: To determine the distribution of HLA-B alleles in the Chinese Yi ethnic group and its association with HIV infection. METHODS: One hundred and six unrelated healthy HIV negative and 73 HIV positive Chinese Yi ethnic individuals were typed by PCR-SSP. RESULTS: The frequency of alleles B*07, Bx 35, and B*46 were increased in HIV-1-positive subjects, whereas the alleles B*55, B*44 and B*78 were absent in the HIV-infected persons studied. The B*46 allele was present in a significantly higher gene frequency among HIV-1-positive individuals (P=0.02, OR=3.32, 95% CI=1.13-9.78) compared with control subjects. CONCLUSION: HLA-B*46 may be associated with its susceptibility to HIV-1 infections.

Community-based survey of HCV and HIV coinfection in injection drug abusers in Sichuan Province of China.

AIM: To investigate the prevalence and risk factors of HCV/HIV coinfection in injection drug abusers (IDAs) in Lianshan Yi Autonomous Prefecture of Sichuan province, China. METHODS: From November 8, 2002 to November 29, 2002, a community-based survey was conducted to investigate the demographic characteristics, patterns of shared injectors devices and sexual behaviors in IDAs. Blood samples were also collected to test HCV and HIV infection. A total of 379 subjects were recruited in the study through community outreach and peer recruiting methods. RESULTS: Of the 379 IDAs, the HCV prevalence and HIV prevalence were 71.0% and 11.3%, respectively, and HCV/HIV coinfection was 11.3%. HCV infection was found in 100% and 67.3% of HIV-positive and HIV-negative IDAs, respectively. HIV prevalence was 16.0% in HCV positive IDAs while none of the HCV negative IDAs was positive for HIV. Ethnicity, shared needles or syringes and cotton in the past 3 mo and syphilis infection were associated with HCV/HIV coinfection shown by univariate analysis using chi-square test. Multivariate logistic regression analysis showed that shared needles or syringes in the past 3 mo (Odds ratio=3.121, 95% CI: 1.278-7.617, P<0.05) and syphilis infection (Odds ratio=2.914, 95% CI: 1.327-6.398, P<0.01) were significantly associated with HCV infection. No statistically significant association was found in univariate analysis between sexual behaviors and HCV/HIV coinfection. CONCLUSION: Shared needles and syringes in the past 3 mo and syphilis infection were significantly associated with HCV infection. Further sero-epidemiological prospective cohort studies should be conducted to clarify the impact of syphilis and high risk sexual behaviors on HCV transmission through unprotected sexual intercourse.