A study on genotypes of hepatitis B virus among hemodialysis patients in Khuzestan province

Introduction and objective: hepatitis b virus (hbv) is a member of hepadnaviridae and a major causative agent of chronic and acute hepatitis, liver cirrhosis and hepatocellular carcinoma. genotype determination of hbv is based on pcr-rflp and sequencing of genome of the virus. the genotype formation is mainly due to mutations of hbv precore, s, and ymdd (tyrosine-methionine-aspartate-aspartate motif in the c domain of the hbv dna polymerase gene) genome area. moreover, some of the mutant hbv remains undetectable by serological tests (occult hepatitis). since the genotypes of hbv and occult hepatitis b has not been studied in our area, this study was conducted to determine both occult hepatitis b infection and genotypes among hemodialysis patients. materials and methods: two hundred and fifty hemodialysis patients were selected in this study. the sera of the patients were collected and the extracted dna was used as template of pcr to amplify a 479bp fragment of the viral genome. the pcr products were digested by ava2 and mbo1 restriction enzymes. based on rflp patterns, the genotypes were determined. the hbv markers including; hbv surface antigen (hbsag), hepatitis bc antibody (hbcigg), hepatitis b virus e antigen (hbeag) and hepatitis b virus e antibody (hbeab) were carried out for all the patients by elisa test. results: fifty (20%) out of 250 sera showed positive hbv by pcr. out of the 50 positive cases for hbv, 46(92%) belonged to genotype d2 and 2(4%) cases of them were b6 genotype. ten cases were positive for hbv by pcr test but negative by elisa test (4% occult hepatitis). conclusion: prevalence of hbv infection was high among the dialysis patients (20%), and occult hepatitis b was 4% in these patients. the dominant genotype of hbv was d2 (92%) followed by genotypes b6 (4%) in hemodialysis patients.