a UMAP of integrated PsA blood, synovial fluid and synovial tissue memory CD4 and CD8 T cells (paired blood and synovial fluid from three patients; synovial tissue from two other patients). Clusters coloured red comprise CD8 cells, clusters coloured blue are CD4 cells. Clusters in grey contain mixed CD4 and CD8 populations. b Heatmap showing memory CD4 and CD8 immune subset signatures. The relative expression of marker genes (columns) across cell clusters (rows) is shown. c–e UMAPs showing the contribution of PBMC, SFMC and synovial fluid-derived T cells to the integrated UMAP from (a). f–h Volcano plots showing differential expression of genes between blood and synovial fluid T cells in HLA-DR-low (f), HLA-DR-high (g) and ZNF683+ (h) clusters (Supplementary Data 3a–c). Statistics calculated using two-sided Wilcoxon Rank Sum test with Bonferroni correction. Genes where adjusted p value < = 1E−04 and average logFC is greater than 0.75 or less than −0.75 are labelled and shown as red circles. Dotted lines indicate significance and average logFC cut-off for displaying labelled genes (paired blood and synovial fluid from three patients). Source data are provided as a Source Data file.