Fig. 2

Specific activation of EP4 promotes Th17 cell expansion and upregulation of IL23 receptor in ankylosing spondylitis. a Representative example of flow cytometric analysis and b summary of the results of IL-17 measurement in purified CD4⁺ T cells from healthy controls (HC), patients with AS, and patients with RA after 4 days of in vitro cell culture in the presence of the EP4 agonist misoprostol, PGE₂, or the EP2 agonist butaprost (HC n = 11; AS n = 8; RA n = 11; *p < 0.05, **p = < 0.01, p value calculated using Friedman test). c RT-PCR analysis of IL23R mRNA expression in CD4⁺ T cells from patients with AS after 3 days of in vitro stimulation with PGE2 or an EP4 or EP2 agonist. Data are shown as relative expression. d Flow cytometry analysis of IL-23 receptor expression in IL-17⁺ CD4⁺ T cells from patients with AS after 3 days of in vitro stimulation with an EP4 agonist (*p < 0.05; p value calculated using Wilcoxon test) or e after 3 days of stimulation with PGE₂ or an EP2 agonist. f Analysis of IL23R expression by RT-PCR and by flow cytometry (g) in CD4⁺ T cells from patients with RA, PsA, and SLE after 3 days of in vitro stimulation with PGE₂ or an EP4 or EP2 agonist. Data are shown as relative expression (RT-PCR: n = 6; *p < 0.05, **p < 0.01; flow cytometry: RA n = 5, PsA n = 4, SLE n = 3; p value was calculated using Friedman test). The percentage of positive cells is expressed as mean ± SEM