Table 1.

Summary of studies involving aberrant Tfh and Tfr cells in human RA.

Tfh Cells in RA	Findings
Arroyo-Villa et al. [65]	RA patients with active disease have a higher frequency of Tfh cells and a higher Tfh/Tfr ratio resulting from lower Tfr frequencies
Zhang et al. [66]	Increased frequencies of Tfh cells and IL-21 in RA patients which correlates positively with DAS28
Wang et al. [67], Zhou et al. [69]	Increased frequencies of Tfh cells in newly diagnosed RA patients correlating with activated B cells and DAS28
Niu et al. [68]	Elevated frequencies of Tfh cells, IL-21 and PD-1 in RA patients with active disease
Nakayamada et al. [70]	Higher proportions of Tfh cells in RA patients with active disease and, treatment with Abatacept reduces Tfh cell levels.
Su et al. [71]	Elevated frequencies of Tfh cells in RA patients compared to HCs
Tfr cells in RA
Su et al. [71]	Decreased frequencies of Tfr cells in RA patients compared to HCs
Wang et al. [72]	Increased levels of Tfr cells in RA patients compared to HCs
Macdonald et al. [73]	Elevated percentages of Tfr cells in RA patients
Liu et al. [74]	Higher frequencies of Tfr and Tfr/Tfh cell ratio in RA patients with stable remission

RA; Rheumatoid Arthritis, Tfh; T follicular helper cells, Tfr; T follicular regulatory cells, PD-1; Program cell death 1, DAS28; Disease activity score evaluated in 28 joints, HCs; healthy controls.