PDCD1 and rheumatoid arthritis: The improvement in disease activity observed in RA patients was associated with the tolerogenic effects of the peptide-based therapy DEN-181, including an early expansion of PD1+ collagen type II– and citrullinated vimentin–specific T cells, followed by a reduction in ACPAs, an increase in CCR7+ naïve T cells and a decrease in memory B cells (204).