PDCD1 and rheumatoid arthritis: MicroRNAs (miRNAs) predicted to target programmed death 1 (PD-1) or its ligands, TIM-3, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) or IRF9 downregulated in non-stimulated rheumatoid arthritis (RA) peripheral blood mononuclear cell (PBMC) compared with non-stimulated healthy control (HC) PBMC.