Objectives: To compare expression of salivary protein in Sjögren`s syndrome patients and healthy subjects.
Methods: Unstimulated whole saliva was collected from 16 females age matched individuals; 8 healthy subjects, and 8 primary SjS patients. Proteins were extracted and separated by 2-D SDS-PAGE using pH range of 3-10 followed by 9.5-16.5% gradient gel. Analytical gels were visualized by ammonical silver stain and digitalized using PDQuest software. Selected protein spots of interest were excised from a preparative gel stained by Coomassie Brilliant blue. The spots were analyzed by electrospray ionization - tandem mass spectrometry (ESI-MS/MS). Obtained data were searched against the SwissProt and NCBI non-redundant protein databases using Mascot software.
Results: We observed sub-division of SjS 2D-gels into 2 groups; a major group (6 patients) that demonstrates significant protein expression differences from healthy subjects and another group (2 patients) with similar pattern to the 8 healthy subjects.
Conclusions: This preliminary study demonstrates salivary protein expression differences between SjS and healthy subjects. Among the SjS group we found two patterns of protein expression with no direct correlation to their clinical, serolgic or histopathology state. This sub-division should be further explored. It may be possible that these two patterns represent different severity states of SjS or it may represent different stages of this disease.