To identify features of the T cell receptors (TCRs) present on clonally expanded T cells in the joints of patients with similar types of childhood rheumatic disease. Vbeta8 and Vbeta20 TCRs were selected as prototypic for polyarticular juvenile rheumatoid arthritis (JRA) and pauciarticular/juvenile spondylarthropathy (SpA), respectively.
The portion of the TCR beta chain involved in antigen recognition in the synovial tissue, synovial fluid, and peripheral blood from patients with JRA and juvenile SpA was cloned and sequenced. The frequency of expanded clonotypes, size of expansions, the Jbeta region, and sequence motifs were determined for >2,000 sequences.
The majority of Vbeta20 and Vbeta8 clonal expansions were found in the joint rather than the peripheral blood. While instances of both Vbeta8 and Vbeta20 clonal expansion were detected in all disease types, the features of these expanded clonotypes were specific for disease type and Vbeta family. For example, Vbeta20 clonal expansion was characterized by many small expanded clonotypes in samples from patients with pauciarticular JRA and juvenile SpA while single large Vbeta8-specific expansions were found only in patients with polyarticular disease. Motifs specific to individual patients were identified, and for Vbeta20 clonotypes, a motif was found in synovial tissue samples.
Identification of common TCR features in oligoclonal expansions within individual patients and between patients with the same type of JRA suggests the recognition of a common or limited group of antigens in these diseases.