Phenotype characteristics of CD4+CD25+/highCD127low/-T cells in rheumatoid arthritis and osteoarthritis patients in different compartments. Samples were stained with anti-CD4–fluorescein isothiocyanate (clone 2A3), anti-CD25–allophycocyanin (clone RDR5), and anti-CD127–peridinin chlorophyll protein complex cychrome 5.5 (clone RDR5) to identify CD4+CD25+/highCD127low/- cells. The cells were further stained for the following surface markers: CD45RA (clone HI100; BioLegend), CD45R0 (clone UCHL1; BioLegend), CD69 (clone FN50), CD152 (cytotoxic T-lymphocyte antigen 4 (CTLA-4), clone BN13), CD154 (CD40L, clone 89-76), CD274 (PD-L1, clone 29E.2A3; BioLegend), CD279 (PD-1, clone MIH4) and CD62L (L-selectin, clone DREG-56). Cells stained with isotype controls are shadowed in the histograms. The boldface line represents the CD4+CD25+/highCD127low/- T cells. GITR, Glucocorticoid-induced tumour necrosis factor receptor; OA, Osteoarthritis; PB, Peripheral blood; RA, Rheumatoid arthritis; SM, Synovial membrane.