CLONOTYPE ANALYSIS OF PERIPHERAL-BLOOD T-CELLS AND AUTOANTIGEN-REACTIVE T-CELLS FROM PATIENTS WITH MIXED CONNECTIVE-TISSUE DISEASE

T cells that recognize autoantigens may play a central role in the aut oimmune response. We have previously shown that autoantigen-reactive T cells (CD4(+)) to U1-small nuclear ribonucleoprotein A were found in the PBMC of patients with systemic lupus erythematosus or mixed connec tive tissue disease. To reveal clonotypes of such T cells that spread to the periphery, T cell clonal accumulations and their TCR-beta chain variable gene usages in fresh PBMC from eight patients with mixed con nective tissue disease were analyzed by a new method of single strand conformation polymorphism applying to TCR gene detection. The results revealed that the numbers of accumulated T cell clones (mean: 24.3 clo nes) were greater than the numbers of clones detected in healthy donor s (mean: 4.0 clones). Frequently used VP genes in these accumulated T cell clones were V beta 1, 3, 4, 5.2, 14, and 16. After the stimulatio n for these samples with the soluble recombinant U1-small nuclear ribo nucleoprotein A protein, proliferative T cell responses were observed. We found that T cell clones expressing more restricted TCR V beta gen es (1, 3, 5.2, and 14 families) accumulated in vitro. These results su ggest that autoantigen-reactive oligoclonal T cell accumulations are p resent in the peripheral blood from systemic autoimmune disease patien ts.