Immunological evaluation in oral lichen planus with chronic hepatitis C.

Oral lichen planus (OLP) is frequently associated with hepatitis C virus (HCV) infection. We have previously reported that the pathogenesis of OLP arises from host rather than viral factors. In this study, we investigated the role of these factors in 41 patients with chronic hepatitis C: 22 with OLP (group 1) and 19 without OLP (group 2). All patients had antibodies to HCV (anti-HCV) and were serum HCV RNA-positive; none were HBsAg-positive. Immune abnormalities in serum were evaluated by testing for antinuclear antibody (ANA), rheumatoid factor (RF) activity, immunoglobulins (IgG, IgM, and IgA), and cryoglobulin. The rate for ANA positivity and IgM levels were significantly higher in group 1 than in group 2 (P < 0.05). Mean age in group 1 was significantly higher in group 2 (P = 0.0001). Of the factors tested, ANA, IgM, and age, logistic regression showed that age correlated independently with OLP (P = 0.003). In 5 patients in group 1, the infiltrating lymphocytic subsets of the OLP lesion were examined histopathologically. Predominant T cell infiltration was shown in all 5 patients. In addition to host factors, wer also examined viral factors in both groups of patients, measuring serum HCV RNA level and determining HCV genotype. There were no significant differences between the groups in these viral factors. This study suggested that host factors induced by the HCV infection are more important than viral factors in the pathogenesis of OLP associated with hepatitis C.