Comparison of ISG15, IL28B and USP18 mRNA levels in peripheral blood mononuclear cells of chronic hepatitis B virus infected patients and healthy individuals.

Aim: The purpose of this study was to evaluate the expression level of Interferon-stimulated Gene 15 (ISG15), Interleukin28B (IL28B) or IFN-lambda-3 and Ubiquitin specific peptidase 18 (USP18) genes in Peripheral Blood Mononuclear Cells (PBMCs) of patients with chronic active and inactive hepatitis B in comparison with healthy individuals.

Background: Despite the presence of the vaccine for hepatitis B virus (HBV), it remains a public health challenge. The effort to uncover the immune genes attributed to infection outcome is going through.

Methods: This Cross-sectional study was conducted on hepatitis B infected patients that were admitted to the Clinic of Liver diseases, Shiraz, January-November 2016. Patients were divided into two groups including active and inactive chronic regarding relevant World Gastroenterology Organization Global Guideline. They were mono-infected with HBV, and HCV or HIV co-infection was excluded from the study. Gene expression analysis was performed on fresh PBMCs samples with the help of Real-time PCR method.

Results: Interleukin 28B gene expression showed no statistically significant difference between the three studied groups (P>0.05). The expression level of ISG15 was significantly higher in the healthy control group compared to active (P= 0.0068) and inactive chronic subjects (P<0.0001). Similarly, USP18 expression level in the control group was also significantly higher compared to the active (P= 0.0228) and inactive chronic patients (P=0. 0226).

Conclusion: The results of this study showed that the expression level of ISG15 and USP18 but not IL28B were higher in healthy individuals than in those infected with HBV. This difference expression may highlight the role of ISG15 and USP18 in the immune-related mechanism of HBV infection.