RESUMO
Occult hepatitis B infection [OBI] is a form of hepatitis, which in despite of absence of detectable HBsAg, HBV-DNA is present in peripheral blood of patients. Evaluation the relationship between alleles of+1188 in region of IL-12 with serum level of cytokine in patients with occult HBV infection. In this study, the plasma samples of 3700 blood donors were tested for HBsAg and anti-HBc by ELISA. The HBsAg negative ve and anti-HBc positive samples were selected and screened for HBV-DNA by PCR. HBV-DNA positive samples assigned as OBI cases and PCR-SSP and ELISA were performed to examine the polymorphisms in region of [+1188 and serum level of IL-12] respectively. The results showed that there is a significant difference in CC allele of+1188 region of IL-12 in two groups and no difference in the other evaluated genes. There is not any significant difference in serum level of IL-12 between OBI patients and controls. Our results also showed that there isn't any significant statistically relation between alleles of+ 1188 region of IL-12 with serum level of cytokine. According to the results of this study it could be concluded that OBI patients unable to produce enough quantity of IL-12 and it may be related to different IL-12 gene. CC allele was associated with OBI, hence, it seems that +1188 region of IL-12 gene has an important role in expression of IL-12 gene. Evaluation of relation between polymorphisms in +1188 region of IL-12 gene and its expression. In vitro and under mitogene affect can useful because no association was seen between serum level of IL-12 and alleles of this region