A3AR expression level in PBMCs from RA patients. (a) Newly MTX treated RA patients. Western blots of the four patients at baseline and 10 weeks after MTX treatment are presented. Representative Western blots are shown at the bottom. (b) RA patients undergoing chronic treatment with MTX. Results are expressed as means ± standard error for 30 patients. (c) Double-stained immunofluorecence analysis of PBMCs from RA patients. A3AR expression on the cell surface of the CD4+ T cells was found. (d) Incubation of PBMCs from MTX-treated RA patients for 1 hour in RPMI 1640 supplemented with 10% foetal bovine serum in the presence of with CF101 (10 nmol/l) resulted in decreased expression of A3AR. A3AR, A3 adenosine receptor; AIA, adjuvant-induced arthritis; MTX, methotrexate; PBMC, peripheral blood mononuclear cell; RA, rheumatoid arthritis.