Background/Purpose:

RA is associated with shared epitope (SE)+ HLA-DRB1 alleles, including HLA-DRB1*0401, and development of anti-citrullinated protein autoantibodies. The preferential binding of citrullinated vimentin to HLA-DRB1*0401 and the correlation between disease activity and the frequency of citrullinated vimentin-specific T cells suggest that citrullinated vimentin selects and expands antigen-experienced T cells in SE+ RA patients. TCR diversity is generated through gene rearrangement, insertions and deletions of the genes encoding the Vα and Vβ chains. TCR Complementarity Determining Regions (CDR) interact directly with peptide-HLA (pHLA). If selection bias has occurred as a result of TCR-pHLA interactions, different individuals may share a similar TCR repertoire to a given pHLA. While deep sequencing synovial tissue has demonstrated oligoclonality, the antigens recognised by these clones are unknown. To obtain more direct evidence that presentation of citrullinated-vimentin shapes the repertoire in SE+ individuals, we profiled TCR repertoire diversity among single vimentin(59-71)cit-64-specific CD4+ T cells.

Methods: Single vimentin(59-71)cit-64-specific CD4+ T cells were sorted from peripheral blood mononuclear cells (PBMC) of 8 HLA-DRB1*0401+ RA patients and 6 HLA-DRB1*0401+ healthy controls (HC), based on staining with fluorescent pHLA tetramers. Sorted cells were simultaneously analysed for expression of CD25 and CD127. At sampling, 2 of the 8 patients had been treated for 18 and 41 months, respectively, 1 had recent-onset untreated RA and 5 had recent-onset RA. PBMC were collected pre- and 1-9 months post-treatment with disease modifying anti-rheumatic drugs. Paired TCR TRAV and TRBV sequences were analysed using multiplex, nested PCR and sequencing.

Results:

A total of 486 vimentin(59-71)cit-64-specific CD4+ T cells with productive TRAV and TRBV sequences were analysed from 8 patients and 6 HC (255 TRAV and 370 TRBV from RA patients; 97 TRAV and 116 TRBV from HCs). Among these T cells, the repertoire encoding TCRα and TCRβ was highly diverse in all patients and HC, and included a large number of unique CDR3 sequences. However, TCR usage in the epitope-specific population differed between RA patients and HC. In RA patients, TRAV26-1 (8%) and TRBV20-1 (13%) predominated while in HC, TRAV13-2 (12%) and TRBV20-1 (12%) were dominant. We did not observe preferential usage in the length of CDR3α or CDR3β. Repeated sequences of individual clonotypes were observed in 3/8 RA patients, but in none of the 6 HC. This oligoclonality was present in pre- and post-treatment samples, and in some cases the same sequences were observed in the same individual across time-points. The repeated sequences were exclusively derived from CD25+CD127+ effector CD4+ T cells.

Conclusion: These data demonstrate a wide range of possible TCRs available for recognition of the vimentin(59-71)cit-64 epitope in PB CD4+ T cells of RA patients and HC. While CD4+ T cells recognising citrullinated self-antigens are present in RA patients and HC carrying HLA-DRB1*0401, repeated clonotypic sequences only among RA patients suggests selective citrullinated self-antigen-driven oligoclonal effector T cell expansion in disease.

« Back to 2015 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/profiling-at-the-single-cell-level-reveals-evidence-for-antigen-driven-oligoclonal-expansion-of-citrullinated-vimentin-specific-cd4-t-cells-in-peripheral-blood-of-rheumatoid-arthritis-ra-patients/