ab1901

Immunohistologic markers of immune activation and changes of glycosylation of serum proteins in primary Sjögren's syndrome

V. Riccieri¹, A. Spadaro¹, L. Saso², G. Valentini², E. Taccari¹, B. Silvestrini²

¹Department of Medical Therapy, Rheumatology Unit; ²Department of Pharmacology of Natural Substances and General Physiology, University of Rome "La Sapienza", Italy

ABSTRACT
Obiective
To assess the possible correlations between the immune activation of certain surface antigens at the lip salivary gland (LSG) level, and changes in glycosylation of serum proteins in primary Sjögren's syndrome (SS).

Methods
LSG biopsy samples were obtained from 22 SS patients (mean age 56.3 years; mean disease duration 70.8 months) and prepared for immunohistochemical analysis using murine monoclonal antibodies for interleukin-2 receptor (IL-2R) (CD25) and for the class II major histocompatibility antigen HLA-DR. The glycosylation of serum proteins was evaluated in all patients by an enzyme-linked lectin assay (ELLA) using concanavalin A (Con A).

Results
In LSG specimens the presence of IL-2R was observed at the infiltrating level, mainly periductally, in 13 (59%) cases and on the epithelial cells of 14 (64%) patients. In 13 out of 22 SS patients (59%) a marked positivity both of the infiltrates and of the epithelium was found for anti-HLA-DR monoclonal antibody. The degree of expression of different antigens on LSG samples was correlated with their histologic class according to Tarpley evaluation. The positivity for IL-2R and HLA-DR molecules on glandular tissues was correlated. A significant increase in the total Con A reactivity of serum proteins was found in those patients expressing IL-2R and HLA-DR antigens on LSG specimens.

Conclusions
The co-expression of IL-2R and HLA-DR antigens on both the epithelium and infiltrates of LSG is consistent with a participation of these cells in the immune process of SS. Moreover, changes in the glycosylation of serum proteins seem to be related to the presence of these immunoactivation markers of the disease at the LSG level, suggesting that the control of protein glycosylation could be mediated by the same mechanisms involved in the tissue damage of SS.

Key words
Sjögren's syndrome, lip salivary glands, protein glycosylation.

Please address correspondence and reprint requests to: Dr. V Riccieri, Department of Medical Therapy, Rheumatology Unit, University of Rome "La Sapienza", P.le Aldo Moro 5, 00185 Rome, Italy.