PRDM1 and rheumatoid arthritis: The Spike-binding B cells were significantly enriched in CD27+ memory cells (p = 0.0078 and p = 0.031 for HD and patients, respectively), the CD71 activation marker (p = 0.031, D2m1 and p = 0.0078, D3m1 for HD and p = 0.031, D2m1 and p = 0.031, D3m1 for RA, respectively), and low-level expression of Blimp-1 transcription factor (significant only after D3 in patients, p = 0.031).