Investigation of stimulator of interferon genes (STING) expression levels among individuals with chronic hepatitis b infection and who have naturally acquired immunity against 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, using a number of second messengers to activate specific transcription factors for synthesis of cytokines such as interferon (IFN) alpha, IFN beta, tumor necrosis factor (TNF) alpha and interleukin (IL)-6 and is thought to be an important member of the immune system against HBV. The main purpose of this study is 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 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) was isolated afterwards. Total RNA was isolated from PBMC. After cDNA synthesis of the total RNA, STING gene expression levels were determined by real-time polymerase chain reaction (RT PCR) method. After RT PCR, normalization was performed by applying the 2^(-∆∆CT) formula. 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. To our knowledge, this is the first study investigating the role of STING expression in chronicity of HBV. Although the average expression level of naturally immunized individuals was calculated as approximately 10% higher than that of hepatitis B infected patients, no significance was found, statistically.