Antibodies to mutated citrullinated vimentin in patients with chronic hepatitis C Virus genotype IV infection-related arthropathy

Abstract

One of the extra-hepatic manifestations of hepatitis C virus (HCV) infection is polyarthritis that mimics rheumatoid arthritis (RA). Anti-mutated citrullinated vimentin (MCV) was recently introduced in the diagnostic workup of RA, but its exact role in HCV infection and its related arthropathy is still unclear. The aim of the study is to determine the prevalence of anti-MCV antibodies in HCV-infected patients with or without articular involvement, and to investigate whether anti-MCV antibodies have an additional role to anticyclic citrullinated peptide (CCP) antibodies and rheumatoid factor (RF) in differentiating patients with RA from patients with HCV-related arthropathy. Fifty-five HCV-infected patients (HCV RNA positive) and 30 RA patients (fulfilling the American College of Rheumatology classification criteria for RA and negative for HCV) were included. Anti-MCV antibodies, anti-CCP antibodies, RF and cryoglobulins were measured. Articular involvement in hepatitis C patients was evaluated. Articular involvement was detected in 30/55 (54.5%) of HCV-infected patients. The most frequent pattern was symmetric polyarthralgias and the most frequent joints to be involved were the wrists, metacarpophalangeal joints, shoulders and knees. In HCV arthropathy, anti-MCV was positive in 9/30 (30%), anti-CCP in 0% and RF in 22/30 (73.3%). Whereas, in chronic HCV without arthropathy, anti-MCV was positive in 8 patients (32%), anti-CCP in one patient (4%) and RF in 23/25 (92.0%). There was no significant difference between the two HCV groups as regards the frequencies of anti-MCV (P = 0.89), anti-CCP (P = 0.93) and RF (P = 0.15). In RA, anti-MCV was positive in 93.3% anti-CCP in 96.7% and RF in 86.7%. There was no significant difference in RF between RA and HCV arthropathy (P = 0.33). Meanwhile, there was a highly significant difference between both groups regarding anti-MCV and anti-CCP (P < 0.0001 for each). The sensitivity of anti-MCV, anti-CCP and RF for RA was 93.3, 96.7 and 86.7%, respectively. Whereas their specificity was 69.1, 98.2 and 18.2%, respectively. In addition, the mean levels of anti-MCV and anti-CCP were significantly increased in RA than in all HCV patients (P = 0.038 and P < 0.0001, respectively). Meanwhile, there were no significant differences in mean levels of anti-MCV and anti-CCP between HCV patients with arthropathy and those without arthropathy (P = 0.11 and P = 0.73, respectively). Also, there were no differences in mean RF between both HCV groups. There was a significant positive correlation between anti-MCV and anti-CCP levels in patients with HCV-related arthropathy (r = 0.39, P = 0.032) and in those without arthropathy (r = 0.578, P = 0.002). Cryoglobulins were detected in 7/30 HCV-related arthropathy (23.3%) and were positively correlated with anti-MCV(r = 0.485, P = 0.007). Anti-CCP still attains the major role in differentiating RA from HCV arthropathy. Anti-MCV seems to play no additional role in this aspect. The role of mutation of vimentin in the pathogenesis of HCV arthropathy is not as clear as it is for RA and needs further investigation.