PRTN3 and rheumatoid arthritis: Recently, the T peripheral helper cells have gained much interest in RA, as possible cells to interact with B cells in extrafollicular responses, either in conjunction with germinal centre reactions in secondary lymphoid organs or in the inflamed joints.116 117 Circulating T peripheral helper (HLA-DR+Tph) memory cells have been shown to be increased in both ACPA+at risk individuals, pre-RA individuals and RA patients in comparison to HCs.