Regulatory T Cells and Their Association with Serum Markers and Symptoms in Systemic Lupus Erythematosus and Rheumatoid Arthritis

Purpose: Impairment in number and functions of regulatory T cells (Treg) has been found to be associated with many autoimmune diseases including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This study was conducted to identify and compare Treg by flow cytometry using two different staining approaches. Methods: Treg were identified by using CD4+CD25+high and CD4 +CD25+CD127dim staining approaches in SLE and RA patients and healthy controls. Association of both identified Treg levels with various serum markers and clinical presentation was also examined. Results: Blood CD4+CD25+CD127dim cells levels were 11.4+3.57 %, 9.76+2.37 % and 6.95+1.16 %; while CD4+CD25+high cells were 1.46+1.09 %, 0.95+0.59 % and 1.87+1.14 % in SLE patients, RA patients and healthy controls respectively. Number of CD4+CD25+CD127dim cells was higher than CD4+CD25+high cells in blood samples of all three study groups. Levels of CD4+CD25+CD127dim cells were significantly higher in SLE and RA patients, compared to healthy controls, but this difference was not observed for CD4+CD25+high Treg. CD4+CD25+high levels showed significant correlation with serum C4, IFN-gamma and IL-10 levels in healthy subjects and with C4 levels and fever in SLE patients. CD4+CD25+CD127dim levels showed significant association with alopecia and oral ulcers in SLE patients only, but no correlation with measured serum markers. Conclusion: Results suggest that both staining approaches detect Treg differently and also that Treg play different role in pathogenesis of SLE and RA.