In spondyloarthritis (SpA) patients, arthritogenic peptides are presented by the risk allele HLA-B*27 to antigen-specific CD8+ T cells to initiate or maintain an autoimmune response, Deschler et al. (2022) used scTCR-seq to analyze CD8+ T cells in the patient’s synovial fluid (SF) and revealed a preferential expansion of the TCR TRAV- and TRBV- families, common motifs in the CDR3 loop and identical TCR chains across patients. This evidence concerns the gene CD8A and spondyloarthropathy.