PDCD1 and rheumatoid arthritis: Indeed, significant correlations between individual values of ESR and/or serum CRP and PD-1+ cell frequencies and/or median expression were evident in several of the 59 innate/adaptive immunity cell subpopulations/subsets, both in seropositive (11/59; Table 2A, Supplementary Table 7A) and seronegative RA (6/59; Table 2B, Supplementary Table 7B), as well as in PsA (25/59; Table 2C, Supplementary Table 7C).