Significance of antikeratin antibodies in discrimination between rheumatoid arthritis and polyarthritis associated with hepatitis C infection

ABSTRACT

Hepatitis C virus [HCV] injection is often associated with extrahepatic manifestations among which arthropathy is common. HCV-related arthritis commonly present as rheumatoid-like arthritis, with positive rheumatoid factor [RF]. In this study, we try to distinguish between rheumatoid arthritis [RA] and polyarthritis associated with HCV infection using a marker more specific to RA than the rheumatoid factor [RF] namely anitkeratin antibody [AKA]. Serum AKAs were evaluated [by indirect immunofluorescence technique] in two groups of patients ,all were RF seropositive. Group I. 25 patients with HCV associated polyarthralgia or arthritis. Group II 25 patients with RA fulfilling the American college of Rheumatology [ACR] revised criteria. In addition 15 healthy individuals served as controls. All patients of group II as well as healthy controls were HCV seronegative. Other investigations were done for all groups such as erythrocyte sedimentation rate [ESR], C reactive protein [CRP] and antinuclear antibody [ANA]. Plain X ray of both hands were done for all patients to exclude the patients with bone erosion. The study revealed that anitkeratin antibodies were detected in 15/25 [60%] patients with true RA and only 3/25[12%] patients with HCV-related arthritis. AKA were not found in the sera of the healthy controls. The specificity and sensitivity of AKA in RA group were 88% and 60% respectively. Anitkeratin antibody is highly specific for RA and its estimation may increase the diagnostic performance of RA. AKA is a useful marker in discrimination between patients with true RA and those with HCV-associated arthritis