Figure 3.

Expression of P-glycoprotein on lymphocytes from patients with refractory rheumatoid arthritis, as determined by flow cytometry. P-glycoprotein (P-gp) expression on CD4⁺ or CD19⁺ peripheral blood lymphocytes from 20 normal volunteers (open bar) and 100 RA patients [responders, hatched bars; with inadequate response to DMARDs (DMARD-IR), closed bars]. The specific antibodies for staining and flow cytometric analysis were as follows: staining for P-gp using MRK16 [a specific monocloncal antibody (Ab) against P-gp; Kyowa Medex, Tokyo] with FITC-conjugated goat anti-mouse IgG Ab (BD Biosciences Pharmingen), cy-chrome-conjugated CD4 monoclonal Ab, cy-chrome-conjugated CD19 monoclonal Ab (BD Biosciences Pharmingen). Data represent the number of molecules expressed per cell, calculated using standard QIFIKIT beads. Values are mean ± SD of independent experiments. One-way ANOVA were used to compare data between groups. ^aP < 0.05, ^bP < 0.01, by multiple comparison. DMARD: Disease modifying antirheumatic drug; RA: Rheumatoid arthritis.