Hepatitis C virus-associated oral lichen planus: is the geographical heterogeneity related to HLA-DR6?

BACKGROUND: The association between hepatitis C virus (HCV) and oral lichen planus (OLP) is more common in the Mediterranean area and Japan, possibly because of immunogenetic factors. METHODS: Intermediate-resolution HLA-DRB typing by hybridization with oligonucleotide probes was performed in 31 Italian OLP patients with HCV infection, in 45 Italian OLP and in 48 British OLP patients without HCV infection. As healthy controls we included data from 145 unrelated Italian and 101 unrelated British bone marrow donors. RESULTS: Italian HCV+ve OLP patients possessed the HLA-DR6 allele more frequently than Italian and British OLP patients without HCV infection (51.6\% vs. 17.7\% vs. 16.7\%; P corrected = 0.028 and 0.017, respectively). There was no difference in the frequency of the HLA-DR6 allele between Italian and British control subjects. CONCLUSIONS: The present data suggest that HLA-DR6 may be responsible for the peculiar geographic heterogeneity of the association between HCV and OLP.