To study the proportion of regulatory T cells (Tregs) in peripheral blood of patients with rheumatoid arthritis (RA) and investigate the significance of Tregs change in the incidence and inflammatory activity of RA.
Three-color fluorescence flow cytometry was used to detect the CD4, CD25 and CD127 markers in the peripheral blood lymphocytes of 25 RA patients and 31 healthy volunteers (HVs). The proportions of CD4(+)CD25(+), CD4(+)CD25(high), CD4(+)CD25(+)CD127(-) and CD4(+)CD25(high)CD127(-) cells were compared between the two groups and correlation analysis was conducted between Tregs and disease activity indices which including disease activity score (DAS28-4), tender joint count (TJC), swollen joint count (SJC), time of morning stiffness, patient's global assessment of disease activity on a 100 mm VAS by doctor and patients, erythrocyte sedimentation rate and C-reactive protein.
The proportions of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(high)CD127(-) cells in CD4(+) peripheral T lymphocytes were (2.53 +/- 0.85)% and (0.91 +/- 0.32)% respectively in RA group, while they were (3.22 +/- 0.97)% and (1.25 +/- 0.41)% in HV group. Both of the proportions of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(high)CD127(-) cells were lower in RA group comparing with HV group, and both were significantly different between the two groups (P < 0.05). Correlation analysis indicated significant negative correlations of the proportions of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(high)CD127(-) cells with DAS28-4 and TJC (P < 0.05), furthermore, CD4(+)CD25(high)CD127(-) T cells still showed significant negative correlation with the SJC and patient's global assessment of disease activity on a 100 mm VAS by patients (P < 0.05).
The proportion of Tregs decreased in peripheral blood lymphocytes of patients with RA and the abnormality of Tregs may play an important role in the incidence and inflammatory activity of RA.