ANALYSIS OF THE T-CELL RECEPTOR V-ALPHA REPERTOIRE AND CYTOKINE GENE-EXPRESSION IN SJOGRENS-SYNDROME

The antigen receptor diversity of pathogenic T cells in Sjogren's synd rome (SS) may have important implications in the development of the di sease; cytokines from these cells and other sources also play a role i n the pathogenesis of this disease. Using a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) technique, we have at tempted to correlate the presence of restriction in the T-cell recepto r (TCR) repertoire with cytokine profiles. We have analysed TCR V alph a family usage, and the expression of interleukin-1 alpha (IL-1 alpha) , IL-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, interferon-gamma (I FN-gamma) and tumour necrosis factor-alpha (TNF-alpha), in labial biop sies from 12 patients with SS and compared these with samples from thr ee patients with chronic sialadenitis (CS). Only one of the SS biopsie s showed evidence of V alpha restriction (three out of 18 gene familie s). Apart from this, expression patterns were similar in both patient groups. Four of the 12 SS samples demonstrated a 'limited heterogeneit y' of the V alpha repertoire with 3-4 families predominantly expressed , in particular V alpha 1 and V alpha 3. Peripheral blood lymphocytes were unrestricted. The cytokine profiles of the SS and CS biopsies wer e generally similar. However both IFN-gamma and IL-1 alpha were absent from CS, but present in SS samples. The expression of IFN-gamma in th e majority of the samples, together with a lack of IL-4 and IL-13 mRNA , suggests the predominance of a Th1 response in SS. There was no clea r association between the repertoire of V alpha genes expressed and th e cytokine profile observed. However, the V alpha restriction in one S S sample did correspond with a limited diversity of cytokines detected .