Comparison of mRNA Levels of Stimulator of Interferon Genes (STING) in Individuals with Natural Immunity to Hepatitis B Virus (HBV), and in those with Chronic Hepatitis B Infection and without HBV

It has been estimated that currently 350-400 million people have been chronically infected with the hepatitis B virus (HBV) worldwide and approximately one million people die each year due to HBV related diseases. It has been suggested that the viral and host factors, especially the host immune system, may play a role in the chronicity of the HBV infection. Stimulator of interferon genes (STING) is one of the members of the pattern recognition receptor (PRR) that detects the presence of DNA in a human cell, activate synthesis of various cytokines and this protein is thought to be an important member of the immune system against HBV infection. Based on the assumption that there may be a relationship between the differences of STING expression in individuals and HBV chronicity, the aim of this study was to investigate STING gene expression levels in individuals naturally immunized against HBV, in chronic hepatitis B infected patients and in normal individuals who have not been exposed to HBV. A total of 90 volunteers have been included in the study from the age range of 18 to 65, in which the first group consists of 30 individuals naturally immunized against HBV, the second group consists of 30 chronically hepatitis B infected patients while the third group consists of 30 healthy population members who have not been exposed to HBV. Whole blood samples were taken from each participant and peripheral blood mononuclear cells (PBMC) were isolated afterwards. Total RNA was isolated from PBMC. After the synthesis of a:NA from the total RNA, STING gene expression levels were determined by real time polymerase chain reaction (Rt-PCR) method. Normalization was performed by applying the 2(-Delta)(Delta CT) formula after Rt-PCR procedure. STING expression level of the naturally immunized group was calculated as 0.084 +/- 0.026 on average, average STING expression level of healthy population group was 0.082 +/- 0.032 and STING expression level of chronically infected patients group was 0.075 +/- 0.022 on average. There was no statistically significant difference between the groups (p> 0.05). To our knowledge, this is the first study investigating the role of STING expression in the chronicity of HBV. Although there was no statistically significant difference between the groups, the data that showed STING expression levels in naturally immunized individuals were approximately 10% higher than those in chronic hepatitis B patients and was considered as an important finding.