Circulating level of sPD-1 and PD-1 genetic variants are associated with hepatitis B infection and related liver disease progression

Background: Programmed cell death-1 (PD-1) variants and circulating level of soluble PD-1 are associated with susceptibility to malignant and infectious disease. This study aimed to examine the association of PD-1.5 and PD-1.9 variants, and plasma sPD-1 level with hepatitis B virus (HBV) infection and disease progression. Methods: The study cohort consisted of adults infected with HBV (n=513) - stratified by clinical course, including chronic hepatitis B (CHB, n=173), liver cirrhosis (LC, n=134) and hepatocellular carcinoma (HCC, n=206) - and matched healthy controls (HC, n=196). The PD-1.5 (rs2227981 C/T) and PD-1.9 (rs2227982 C/T) genetic variants were genotyped by Sanger sequencing, and plasma sPD-1 levels were quantified by enzyme immunoassay. Results: Plasma sPD-1 levels were significantly higher among patients infected with HBV. The highest plasma sPD-1 levels were observed in patients with CHB, followed by patients with LC and HCC. In addition, the plasma sPD-1 levels correlated positively with liver inflammation [aspartate transaminase (AST): rho=0.57, P<0.00 01; alanine aminotransferase: rho=0.57, P<0.0001], and were positively correlated with liver fibrosis [AST to platelet ratio index score: rho=0.53, P<0.0001). The PD-1.9 TT genotype was less common in patients with CHB compared with patients with LC, HCC, and HCC+LC in both codominant and recessive models (P<0.01), and was found to be a risk factor for HCC predisposition {HCC vs non-HCC: odds ratio (OR) 2.0 [95% confidence interval (CI) 1.13-3.7], P-adj=0.017}. The PD-1.5 CT genotype was associated with reduced risk of acquiring HCC [OR 0.6 (95% CI 0.4-0.9), P-adj = 0.031]. Conclusion: sPD-1 level was associated with liver inflammation and progression of liver fibrosis, and the PD-1.5 and PD-1.9 variants were associated with HBV infection and progression of liver disease. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

This study found that PD-1.5 and PD-1.9 genetic variants, as well as plasma sPD-1 levels, are associated with hepatitis B virus infection and disease progression. Plasma sPD-1 levels are positively correlated with liver inflammation and fibrosis progression, while PD-1.5 and PD-1.9 genetic variants are associated with the risk of hepatocellular carcinoma.