The Study on P-Glycoprotein Expression on Peripheral Lymphocytes of Refractory Rheumatoid Arthritis Patients

Background: To explore the potential mechanism of P-gp expression in multi-drug resistance of refractory RA formation. Methods: 45 patients diagnosed of rheumatoid arthritis from March 2012 to June 2013 were enrolled in our present study and divided into early RA treated group, effective group and refractory group. 15 healthy controls under physical examination were also recruited. The expression of P-gp on peripheral blood lymphocyte was detected by flow cytometry. Pearson's correlation coefficient was used for analyzing of correlation of P-gp expression level with therapeutic outcome. Results: 1. There was no significant difference of P-gp expression on the peripheral blood lymphocytes between patients with early RA treated group and healthy controls (P > 0.05); 2. P-gp expression in effective group was higher than in both healthy controls and early RA treated group (P < 0.05); 3. P-gp expression was significantly higher in RA refractory group than healthy controls as well as early treated group and effective group (P < 0.05); 4. There was no correlation of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP). Rheumatoid factor (RF), disease activity (DAS28 score) with P-gp expression on peripheral blood lymphocytes in RA patients. Conclusion: Increased peripheral blood lymphocytes expression of P-gp may be one of the formation mechanisms of multi-drug resistance in refractory RA patients.