Figure 5.

Transcriptional profiling of entheseal mucosal‐associated invariant T (MAIT) cells and proinflammatory cytokine induction. A, Stratification of MAIT cell subsets based on their expression of T cell receptor Vα7.2 and CD161 in entheseal soft tissue (EST), perientheseal bone (PEB), and peripheral blood (PB) from non‐axial spondyloarthritis patients. MAIT cells expressing tissue resident/memory markers were identified by CD69 expression, and naive/circulating MAIT cells were identified by CD45RA expression. Results are shown as the mean percentage (n = 5). B, Basal expression of cytokines, chemokines, growth factors, signaling molecules, and tissue residency markers. Expression values are the log₁₀ change in threshold cycle relative to the values for hypoxanthine guanine phosphoribosyltransferase (n = 7). The color key denotes differential gene expression, in which values <–1 indicate lower relative expression and values >1 indicate higher relative expression. Gray indicates absence of expression. P = 0.038 by 2‐tailed t‐test for independent samples for the difference in expression of CCR6 by MAIT cells from peripheral blood and MAIT cells from perientheseal bone. C, Intracellular tumor necrosis factor (TNF) and interleukin‐17 (IL‐17) cytokine expression in conditions with or without stimulation with phorbol myristate acetate (50 ng/ml) and ionomycin (1 μg/ml) for 3 hours in the presence of BD GolgiPlug protein transport inhibitor in perientheseal bone–derived MAIT cells (n = 2).