TPH1 and rheumatoid arthritis: In T cell subpopulations, a significant increase in cTh1 cells, cTfh1 cells, and Tph cells, and a significant decrease in cTh17 cells, cTh17.1 cells, and CD8+ Treg cells were observed in the Karuizawa patients with RA compared those from Tsukuba after the IPW adjustments (Fig. 3A).