PCK1 and rheumatoid arthritis: Correlation analysis (Figs. 5B–5E) indicated that, in RA, PCK1 displayed a positive correlation with plasma cells (R = 0.53, P = 0.001), while exhibiting negative correlations with M2 macrophages (R = −0.34, P = 0.043) and memory resting CD4+ T cells (R = −0.42, P = 0.013).