Figure 3. Expansion of CD38hiCD127− CD8 T cells in ICI-arthritis (ICI-A).
a) tSNE visualization of FlowSOM metaclusters of CD8 T cells from ICI-A (n=6), RA (n=5) and PsA (n=5) synovial fluid. The red circle indicates area that includes MC1–3 with increased density in ICI-A. Black circle indicates area of MC5 with lower density in ICI-A. b) Frequency of FlowSOM metaclusters of CD8 T cells from ICI-A, RA and PsA synovial fluid. c) Heatmap of marker expression in CD8 T cell metaclusters. d) tSNE plots of mass cytometry data showing expression of indicated markers on CD8 T cells from ICI-A, RA and PsA synovial fluid. e,f) Biaxial gating (e) and quantification (f) of CD38hiCD127- cells among CD8 T cells from ICI-A, RA and PsA synovial fluid detected by mass cytometry. g) UMAP overlay of signature scores for gene sets that correlate with CD38, IL7R (CD127) or PDCD1 (PD-1) expression derived from bulk RNA-seq data. h) Representative flow cytometric plots and summarized frequency of intracellular granzyme B, perforin, IFN-γ, and TNF in CD38hiCD127− and CD38−CD127+ populations from ICI-A synovial fluid, detected after PMA/ionomycin stimulation (n=3 donors). i) Frequency of intracellular Ki67 in sorted CD38hiCD127− and CD38−CD127+ populations from ICI-A synovial fluid (n=7). Mean ± SD shown. j) Cytotoxicity assay of sorted CD38hiCD127− or CD38−CD127+ CD8 T cells from synovial fluid. Control condition contains only target cells without CD8 T cells. Data represents ≥6 individual experiments. *p<0.05, **p<0.001, ***p<0.0001 by Kruskal-Wallis test in (b), (f), (h) and (i).