Fig. 4

Induction of IgG4 production by circulating follicular helper T (Tfh) cell subsets. Sorted Tfh cell subsets (Tfh1, Tfh2, and Tfh17 cells) from patients with IgG4-related disease (IgG4-RD) or healthy controls (HC) were co-cultured with autologous naive B cells for 7 days, and IgG (a) and IgG4 (b) in the supernatant was measured by cytometric bead array. The IgG4:IgG ratio was calculated (c). **P < 0.05; ***P < 0.0001 for analysis using the Kruskal-Wallis test; *P < 0.05 for analysis using the Mann-Whitney U test