Immune response to extracellular matrix collagen in chronic hepatitis C-induced liver fibrosis

Hepatitis C virus (HCV) infection and its recurrence after orthotopic liver transplantation (OLT) are associated with the remodeling of extracellular matrix (ECM) components [particularly collagen (Col)], which leads to fibrosis. Our aim was to determine whether the development of antibodies (Abs) to self-antigen Col in HCV-infected patients correlates with the fibrosis stage and the peripheral cytokine response. Patients with chronic HCV infection, patients with HCV recurrence after OLT who had undergone a biopsy procedure, and healthy control subjects were enrolled. The HCV subjects (n = 70) were stratified as follows: (1) a non-OLT group without fibrosis (Scheuer stages 0-2), (2) a non-OLT group with fibrosis (Scheuer stages 3-4), (3) a post-OLT group without fibrosis (Scheuer stages 0-2), and (4) a post-OLT group with fibrosis (Scheuer stages 3-4). Serum samples were analyzed for Abs against Col1, Col2, Col4, Col5, and vimentin with enzyme-linked immunosorbent assays. Serum levels of cytokines were measured with multiplex bead immunoassays. The levels of Abs to Col1 were higher in the fibrosis groups versus the no-fibrosis groups and the controls for both non-OLT patients (P < 0.001) and post-OLT patients (P = 0.01). There were increased levels of Abs to Col2, Col4, Col5, and vimentin in the non-OLT fibrosis group (Col2, P = 0.0001; Col4, P = 0.122; Col5, P < 0.0001; vimentin, P = 0.36) and in the post-OLT fibrosis group (Col2, P = 0.006; Col4, P = 0.19; Col5, P < 0.0001; vimentin, P = 0.24) in comparison with the no-fibrosis groups. The non-OLT and post-OLT fibrosis groups demonstrated significantly higher T helper 2 (T(h) 2) and T helper 17 (T(h) 17) cytokine levels and lower T helper 1 cytokine levels in comparison with the no-fibrosis groups. Our results demonstrate that in HCV-infected patients, the levels of Abs to ECM Col1, Col2, and Col5 positively correlate with liver fibrosis, which is associated with a predominantly T(h) 2 and T(h) 17 cytokine profile.