Proportion of T follicular helper cells in peripheral blood of rheumatoid arthritis patients: a systematic review and meta-analysis

<b>Introduction:</b>Alterations in the levels and activity of Tfh may lead to impaired immune tolerance and autoimmune diseases. The aim of this study was to investigate the proportion and types of Tfh cells in the peripheral blood (PB) of RA patients. <b>Areas covered:</b>Comprehensive databases were searched for studies evaluating the proportion of Tfh cells in the PB of patients with RA compared to healthy control (HCs). The proportion of Tfh cells in RA patients was significantly higher than in HCs (SMD 0.699, [0.513, 0.884], p +CXCR5⁺ and CD4⁺CXCR5⁺ICOS⁺, didn’t show significant differences. Furthermore, higher proportion of Tfh cells defined by all definitions and a specified definition (CD4⁺CXCR5⁺PD-1^high) was observed when S⁺RA compared to S⁻RA patients. <b>Expert opinion:</b>The results demonstrate that circulating Tfh are highly elevated in RA patients highlights its potential use as a biomarker and a target for RA therapy.