ANALYSIS OF THE T-CELL RECEPTOR REPERTOIRE IN RHEUMATOID-ARTHRITIS

Objective. To evaluate whether there is a restricted T cell receptor r epertoire in rheumatoid synovium and to analyse the CDR3 region of the V beta families found to be more expressed in the synovial membrane t han in the peripheral blood, in order to ascertain the presence of clo notypic expansion of T lymphocytes. Methods. The level of expression o f individual V beta and V alpha families of the TCR was evaluated in p aired synovial membrane and peripheral blood T cells from 8 female pat ients affected by rheumatoid arthritis, using the RT-PCR method. Nucle otide sequences of the CDR3 region of some V beta families were analys ed in order to identify the presence of conserved sequences. Sequencin g was carried out with the dideoxy chain termination method using modi fied T7 DNA polymerase. Results. All of the V alpha and V beta familie s were amplified in both compartments of the 8 patients. Four patients did not show any preferential expression of the TCR alpha or beta cha ins in synovium compared with peripheral blood. The other 4 patients s howed increased expression of one or more V alpha and/or V beta famili es in the synovium. We did not find any correlation between the durati on of disease, rheumatoid factor status, HLA-DR type and the V gene fa milies which were elevated in the synovium. Analysis of the CDR3 regio n showed the presence of conserved amino acid sequences in the synoviu m, but not in the peripheral blood. Conclusion. The V families found t o be increased in 4 of the 8 patients studied were different, except f or V beta 1 which was more highly expressed in 2 patients. The presenc e of conserved amino acid sequences in the CDR3 region is consistent w ith an antigen-driven T cell expansion at the sire of autoimmune infla mmation. These findings do not support our original hypothesis of the possible usefulness of therapy based on the inactivation or eliminatio n of presumed pathogenic T cells using TCR-derived peptides or monoclo nal antibodies against particular TCRs.