Molecular analysis of human leukocyte antigen class I and class II allele frequencies and haplotype distribution in Pakistani population.

AIM: Distribution of HLA class I and II alleles and haplotype was studied in Pakistani population and compared with the data reported for Caucasoid, Africans, Orientals and Arab populations. MATERIALS AND METHODS: HLA class I and II polymorphisms in 1000 unrelated Pakistani individuals was studied using sequence-specific primers and polymerase chain reaction and assay. RESULTS: The most frequent class I alleles observed were A*02, B*35 and CW*07, with frequencies of 19.2, 13.7 and 20%, respectively. Fifteen distinct HLA-DRB1 alleles and eight HLA-DQB1 alleles were recognized. The most frequently observed DRB1 alleles which represented more than 60% of the subjects were DRB1 *03, *07, *11 and *15. The rare DRB1 alleles detected in this study were HLADRB1 *08 and *09, having frequencies of 0.9 and 1.7%, respectively. In addition, at DRB1-DQB1 loci there were 179 different haplotypes and 285 unique genotypes and the most common haplotype was DRB1*15-DQB1*06 which represented 17% of the total DRB1-DQB1 haplotypes. In our population, haplotype A*33-B*58-Cw*03 comprised 2.8% of the total class I haplotypes observed. This haplotype was seen only in the oriental populations and has not been reported in the African or European Caucasoid. CONCLUSION: Our study showed a close similarity of HLA class I and II alleles with that of European Caucasoid and Orientals. In Pakistani population, two rare loci and three haplotypes were identified, whereas haplotypes characteristic of Caucasians, Africans and Orientals were also found, suggesting an admixture of different races due to migration to and from this region.

Prevalence of hepatitis G virus in Pakistani children with transfusion dependent beta- thalassemia major.

We ought to obtain data on the prevalence of the newly discovered tranfusion transmittable hepatitis G virus in polytransfused b- thalassemia major children. Each individual had received multiple blood transfusions, from 12 to 36 per year. No documentation of prior hepatic infection was available. Serum samples were collected prospectively from the randomly selected subjects and were analyzed for HGV RNA by polymerase chain reaction using primer specific for two different regions of the HGV genome. Among the 100 individuals examined 21 were positive for HGV RNA. Four patients had evidence of dual infection, both HGV RNA and HCV RNA were isolated from their sera. While in one sample presence of both HGV RNA and HBV DNA was established. Only one child was positive for hepatitis E antibodies. The sera of 10 children were reactive for hepatitis B surface antigen whereas 35 individuals were positive for hepatitis C virus antibody. The ALT levels were variable in HGV infected children. Four out of 16 (25%) showed peak ALT levels of 218 IU/I, 8/16 (50%) children demonstrated slightly elevated ALT levels whereas 25% individuals showed normal ALT levels. Alkaline Phosphatase levels were elevated in 90% of the children and 20% patients of this series also had higher GGT levels. The observed AP levels were not statistically different among HGV, HGV/HCV or HGV/HBV groups. Even though the ALT levels were deranged in the children with HGV alone but none of the children had demonstrated symptoms of liver disease, their direct and total bilirubin levels were normal and no complain of jaundice was recorded. In conclusion, our findings suggested that like other blood borne hepatic viruses, HGV is also prevalent in the high risk group of multiple transfused patients in Pakistan but our results support the absence of any causal relationship between HGV and hepatitis.