Investigation of IL-1 beta, IL-1 receptor antagonist and IL-8 gene polymorphisms in patients with chronic hepatitis B and C

The host immune response is closely related to the prognosis of disease and viral persistence in hepatitis B (HBV) and hepatitis C virus (HCV) infections. Although it is well known that cytokines and genetic factors play important roles in the pathogenesis of chronic HBV and HCV infections, the underlying mechanisms are not fully understood. This study was conducted to determine the role of interleukin (IL)-1β, IL-1 receptor antagonist (IL-1RA) and IL-8 gene polymorphisms in chronic hepatitis B and C infections. A total of 361 subjects, 171 with chronic hepatitis B (62 female, 109 male; age range: 18-74 yrs) and 104 with chronic hepatitis C (63 female, 41 male; age range: 25-79 yrs), and a control group of 86 healthy subjects (41 female, 45 male; age range: 18-72 yrs) were included in the study. Following the DNA extractions from peripheral blood leukocytes of the study groups, single nucleotide polymorphisms of IL-1β -31, -511, +3954; IL-1RA and IL-8 -251, -353, -738, -845 gene regions were investigated by using specific primers with real-time PCR method. It was found that the genotype frequency of IL-8 -251 AT (OR: 7.895, p= 0.003) and IL-8 -738 TA (OR: 6.317, p= 0.007) in patients with chronic hepatitis B and the genotype frequency of IL-1β-31 CT (OR: 6.757, p= 0.001), IL-1β -511 CT (OR: 4.060, p= 0.004), IL-8 -251 AT, (OR: 13.622, p= 0.001), IL-8 -738 TA (OR: 14.058, p= 0.001), and IL-8 -845 TC (OR: 2.539, p= 0.004) in patients with chronic hepatitis C was significantly higher than the control group. When the allelic frequency was compared between chronic hepatitis B patients and the control group, it was determined that IL-1β +3954 T allel increased the disease risk 1.5 times (p< 0.05), however, no statistically significant difference was detected for the other allels. It was also determined that IL-8 -845 C allel increased the disease risk 0.6 times in chronic hepatitis C (p< 0.05) and no statistically significant difference was detected for the other allels (p> 0.05). In conclusion, IL-1β -31, -511 and IL-8 -251, -738, -845 gene polymorphisms may play a role in the chronicity of hepatitis B and C infection. In order to determine the importance of this cytokine polymorphisms in hepatitis B and hepatitis C virus infections, large-scale studies with different patient groups such as carriers, chronic hepatitis, cirrhosis, and hepatocellular carcinoma should be conducted to elucidate the molecular mechanisms underlying the disease process.