Expression and significance of Th17 and Treg cells in peripheral blood of patients with systemic lupus erythematosus

Objective: To explore the expression and significance of Th17 and Treg cells in peripheral blood of patients with systemic lupus erythematosus (SLE).

Methods: Thirty active SLE patients (including 17 SLE patients with lupus nephritis), 20 inactive SLE patients and 20 healthy controls were enrolled. The expressions of Th17 cells and CD4+CD25+Foxp3+Treg cells in peripheral blood mononuclear cells (PBMC) were evaluated by flow cytometry. The correlations between the expression of Th17 cells, CD4+CD25+Foxp3+Treg cells and disease activity (SLEDAI), as well as the ratios of Th17 cells and Treg cells (Th17/Treg) in SLE patients and healthy controls were analyzed respectively.

Results: The expression of Th17 cells in PBMC of SLE patients was higher than that in healthy controls [(1.39 ± 0.60)% vs (0.80 ± 0.33)%, P < 0.01] while the expression of CD4+CD25+Foxp3+Treg cells decreased in SLE patients [(3.09 ± 1.54)% vs (6.04 ± 1.49)%, P < 0.01]. The increased expression of Th17 cells and reduced CD4+CD25+Foxp3+Treg cells in PBMC were positively correlated with SLEDAI and negatively correlated with complements C3 and C4. There were increased expression of Th17 cells and reduced CD4+CD25+Foxp3+Treg cells in PBMC of lupus nephritis versus SLE patients without nephritis.

Conclusions: There is an abnormal elevation of Th17 cells and decrease of CD4+CD25+Foxp3+Treg cells in PBMC of SLE patients. The imbalance between Th17 and Treg cells may play a critical role in the pathogenesis of SLE.