Chronic hepatitis B and IL28B rs12979860 polymorphism: preliminary study

Frequency of interleukin 28B rs12979860 C>T variants in Filipino patients chronically infected with hepatitis B virus

Hepatitis B virus (HBV) is one of the most prevalent viral infections worldwide. Nearly 400 million individuals are chronic carriers of HBV. The aim of the present study was to determine the frequency of human interleukin 28B (IL28B) variants among treatment naive Filipino patients clinically diagnosed with chronic hepatitis B (CHB), and to compare the IL28B frequency distribution with various ethnic populations. Fifty-seven CHB patients and 43 normal controls were enrolled in this study. Real-time PCR was performed using the TaqMan genotyping assay for IL28B rs12979860. The allelic frequencies among normal controls were 0.94 and 0.06 for the IL28B rs12979860 C and T alleles, respectively. Eighty-eight percent were identified as homozygous for the IL28B C/C genotype and 12% were identified as heterozygous for the IL28B C/T genotype. Among CHB patients, the allelic frequencies were 0.90 for the IL28B C allele and 0.10 for the IL28B T allele. No IL28B T/T genotype was observed between the two groups. No significant difference in the distribution of IL28B genotypes was observed between normal controls and CHB patients. Allelic frequencies of IL28B among Filipinos were similar with other Asian populations but significantly different from Caucasians. The frequency of rs12979860 C>T variants among Filipino CHB patients has not yet been reported. These data provided new insight into the geographical frequency distribution of IL28B variants. Further studies are needed to determine the possible association between IL28B variants and response to pegylated-interferon-α plus ribavirin combination therapy among Filipino patients chronically infected with HBV.

Human genes involved in hepatitis B virus infection

Persistent hepatitis B virus (HBV) infection is a significant public health problem because it is a major cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC). Roughly one-third of the world population has been infected with HBV and there are about 350 million (5%-6%) persistent carriers. HBV causes 80% of all liver cancer cases and is the second most important carcinogen, after smoking tobacco. There is an approximate 90% risk of becoming a persistent carrier following perinatal infection in infants born to e antigen positive carrier mothers and a 30% risk in pre-school children. Only 5%-10% of adults become persistent carriers following infection. Of individuals persistently infected with HBV, 10%-30% will develop liver cirrhosis and HCC. These highly variable outcomes in both clearance rates and disease outcomes in persistently infected individuals cannot be fully explained by differences in immunological, viral or environmental factors. Thus, differences in host genetic factors may affect the natural history of hepatitis B.