Figure 4.

T regulatory cells expressing B cell help factors are enriched in oligo JIA synovial fluid. (A) Representative flow staining of B cell helper CD4⁺ T cell populations in oligo JIA PB and SF, gated on Tregs (CD3⁺CD4⁺CD127^loCD25⁺FOXP3⁺). In each experiment, the PD-1^hi gate was set by evaluating unstimulated Treg cells from PB (often paired PB and SF sample from the same patient were used) and controls. This PD-1^hi gate was then applied to SF samples from oligo JIA patients evaluated during the same experiment. (B) Percent of Tph-like Treg (PD-1^hiCXCR5^-), PD-1^intCXCR5⁺, and Tfr (PD-1⁺CXCR5⁺) cells among Tregs in the SF of oligo JIA patients (ANA^-: n=11, ANA⁺: n=9, blue circles), and in the PB of oligo JIA patients (ANA^-: n=5, ANA⁺: n=5, red circles), and controls (pediatric: n=5, adult: n=6, black circles). (C) Percent of Tph-like Treg (CD4⁺CD127^loCD25⁺FOXP3⁺PD-1^hiCXCR5^-) cells among total CD3⁺CD4⁺ T cells. (D) Representative flow staining of PD-1^hiCXCL13⁺ T cells in oligo JIA PB and SF, gated on Tregs. (E) Percent of PD-1^hiCXCL13⁺ and PD-1^hiICOS⁺ cells among Tregs in the SF of oligo JIA patients (ANA^-: n=10-11, ANA⁺: n=9), and in the PB of oligo JIA patients (ANA^-: n=5, ANA⁺: n=5) and controls (pediatric: n=4-5, adult). Oligo JIA; oligoarticular juvenile idiopathic arthritis; PB, peripheral blood; SF, synovial fluid; ANA, antinuclear antibody; pedi, pediatric; Tfr, T follicular regulatory cell. Summary data on bar graphs are mean ± standard error. P-value <0.05 (*); <0.01 (**), <0.001 (***), <0.0001 (****). Statistical testing: one-way ANOVA followed by multiple t-tests with Turkey correction.