D-mannose and N-acetylglucosamine moieties and their respective binding sites in salivary glands of Sjogren's syndrome

Objective. Sjogren's syndrome (SS) is an autoimmune exocrinopathy. The mann ose binding lectin (MBL), a pluripotent molecule of the innate immune syste m, is involved in the pathogenesis of autoimmune diseases. We investigated whether specific ligands for MBL and MBL related structures could be reliab le markers in cases of SS. Methods, The labial salivary glands of 19 patients fulfilling the diagnosti c criteria for primary (n = 11) and secondary SS (n = 8) were studied. Seve n healthy women served as controls. Computer assisted microscopy was employ ed to determine quantitatively the percentage of positive structures (acini , ducts, and interlobular connective tissue), the staining intensity, and t he level of staining heterogeneity for 4 glycohistochemical probes includin g wheat germ agglutinin and concanavalin (Con A) as lectins, and mannose an d N-acetylglucosamine as parts of neoglycoproteins. The data were evaluated by discriminant analysis. Results. The data strongly suggest that MBL related structures, if not MBL itself, could play distinct roles in the pathogenesis of primary versus sec ondary SS. Further, quantitative determination of the level of expression o f D-mannose and N-acetylglucosamine and their respective binding sites in l abial salivary gland acini offers a powerful diagnostic tool for distinguis hing primary from secondary SS. Conclusion. In SS labial salivary glands, determination of the level of acc eptor sites for wheat germ agglutinin, Con A, D-mannose, and N-acetylglucos amine provides information on the roles played by glycoforms in SS. The met hodology and data described in this paper should provide pathologists with objective diagnostic markers for SS, Our results should enhance the biologi cal understanding of this pathology.