Salivary mucin MUC7 oligosaccharides in patients with recurrent aphthous stomatitis.

Objectives: The aetiology of recurrent aphthous stomatitis remains unknown. In this study, we investigate the composition of oligosaccharides from mucin MUC7 in recurrent aphthous stomatitis as these heavily O-glycosylated mucins confer many of saliva's protective properties such as defence against mucosal pathogens.

Materials And Methods: Unstimulated whole saliva samples were collected from six individuals, three with recurrent aphthous stomatitis and three corresponding sibling, without this condition. Oligosaccharides from salivary MUC7 were isolated and analysed by liquid chromatography-tandem mass spectrometry.

Results: The types of oligosaccharides identified in the patients and control subjects were similar; however, statistical evaluation indicated semi-quantitative differences between specific oligosaccharide classes. These changes focused on a reduction in terminal glycan residues including fucosylation, sialylation and sulfation on galactose.

Conclusions: This study was able to show differential MUC7 glycosylation in the patients suggesting functional changes to salivary mucins in this condition. The terminal glycans altered in disease have been shown to be important for a range of immunological and bacterial binding roles. Further investigation of these epitopes in a larger study may provide critical insights into the pathology of recurrent aphthous stomatitis.

Clinical Relevance: MUC7 glycosylation is altered in recurrent aphthous stomatitis. This may change the protective properties of this mucin against mucosal pathogens, which may effect this condition.