High incidence of autoantibodies in Taiwanese patients with oral submucous fibrosis

Background: Previous study has shown a high incidence of autoantibodies including antinuclear (ANA), antismooth muscle (SMA), antigastric parietal cell (GPCA), antithyroid microsomal (TMA), and antireticulin antibodies in a small group of 26 patients with oral submucous fibrosis (OSF). The reasons why some of the OSF patients have high titers of autoantibodies in serum have not been completely explained and no further study on autoantibodies in OSF patients has been done in a large group of patients. Methods: In this study, we determined the serum levels of ANA, SMA, GPCA, and TMA in a large group of 109 male Taiwanese patients with OSF by an indirect immunofluorescence technique (for ANA, SMA, and GPCA), and by a semiquantitative microtiter particle agglutination test (for TMA). The presence of serum autoantibodies in OSF patients was further correlated with patients' oral habits and the severity of OSF measured by maximum mouth opening (MMO) and sites of involvement. Results: We found that the frequencies of presence of serum ANA (23.9%), SMA (23.9%), and GPCA (14.7%) in OSF patients were significantly higher than those (9.2, 7.3, and 5.5%, respectively) in healthy control subjects (P<0.01, P<0.005, and P<0.05, respectively). Although the frequency of presence of TMA (5.5%) in OSF patients was also greater than that (2.8%) in healthy control subjects, the difference was not significant (P>0.05). The presence of serum GPCA in OSF patients was significantly associated with daily areca quid (AQ) consumption (P<0.05). The presence of serum ANA in OSF patients associated with daily AQ consumption was of borderline statistical significance (P=0.066). However, no significant correlations were demonstrated between the presence of serum autoantibodies in OSF patients and other variables of oral habits, MMO, and sites of involvement. Conclusions: In this study, all the 109 OSF patients had AQ chewing habit and 73.4% of the OSF patients swallowed the 'juice' of AQ during the chewing process. The presence of serum GPCA and ANA in OSF patients was associated with daily consumption of AQs. AQ chewing caused mucosal microtrauma, and ulcerations facilitated the diffusion of genotoxic and cytotoxic AQ ingredients into the oral and gastric tissues. Altered autoantigens released from AQ ingredients-damaged cells may induce autoantibody production. Higher frequencies of specific HLA-DR antigens in OSF patients may also help autoantibody production. Therefore, we conclude that the high incidence of autoantibodies in OSF patients may be due to AQ chewing habit, toxic AQ ingredients, and genetic susceptibility of the OSF patients.