Plasma levels of soluble PD-1, TIM-3, LAG-3 and galectin-3 and the degree of liver fibrosis in CHC and the impact of successful antiviral treatment on their levels

Chronic hepatitis C (CHC), caused by the hepatitis C virus, commonly leads to liver fibrosis. CHC is also related to T-cell exhaustion, phenotypically manifesting as overexpression of inhibitory receptors (iRs), e.g., programmed death receptor-1 (PD-1), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) and lymphocyte activation gene 3 (LAG-3), which have corresponding plasma-soluble analogs. Galectin-3 (Gal-3) is a pro-fibrotic and pro-inflammatory molecule, but its role in CHC is controversial. The study aimed to assess the relationship between plasma levels of soluble PD-1 (sPD-1), sTIM-3, sLAG-3 and Gal-3 and the degree of fibrosis in CHC and successful CHC treatment effect on these markers. The study comprised 98 CHC patients, qualified for treatment with direct-acting antivirals. Plasma samples were collected prior to and six months post-treatment. iRs were determined by ELISA. sPD-1 levels were significantly higher in more advanced fibrosis (F2 + F3 vs. F0/1). Regardless of the degree of fibrosis, sPD-1 and sLAG-3 levels significantly decreased after therapy. sTIM-3 levels also decreased, however, mostly in patients with no or mild (i.e., F0/1) fibrosis. Furthermore, Gal-3 increased in patients with more advanced fibrosis (F2 + F3). sPD-1 is associated with liver disease stage in CHC and effective treatment is related to the iRs levels reduction.