ABSTRACT
Occult Hepatitis B Infection [OBI] is a form of hepatitis in which despite of absence of detectable HBsAg, HBV-DNA is presented in patients peripheral blood. Responsible mechanisms of progression of OBI are unknown yet, but some investigators believed that the genetic and immunological parameters may be different. Cytokine network system could be leading alteration in viral immune response. IL-4 as an anti-inflammatory cytokines causes decreased immune function. Thus, regulatory factors which influences expression and function of IL-4 can be effective on immune system functions. As polymorphic variation in cytokine genes has regulatory effects on their expression and functions, this study investigates the association of-590 region polymorphisms of IL-4 with OBI. Determination of association between IL-4 polymorphisms with OBI. In this study, the plasma samples [FFP] of 3700 blood donors were tested for HBsAg and anti-HBs by ELISA. The HBsAg negative and anti-HBc positive samples were selected and screened for HBV-DNA by PCR. HBV-DNA positive samples assigned as OBI cases while HBV-DNA negative samples were used as control and PCR-RFLP was performed to examine the presence of polymorphisms in -590 regions of IL-4 genes of patients with OBI. 352 [9.51%] Out of 3700 blood samples were negative for HBsAg and positive for anti-HBc antibody. HBV-DNA was detected in 57[16.1%] of HBsAg negative and anti-HBc positive samples. Our results showed that none of the alleles had significant difference between patients and control group. Our results demonstrated that there is no significant difference between patients with OBI and control cases. Therefore, it seems that there is not any relation between these alleles and OBI and more study should be done on polymorphisms in other to cytokine genes in patients with OBI