[Expression of CD4+ CD25+ CD127(low/-) T cells in patients with systemic lupus erythematosus].

OBJECTIVE: To detect the new and old surface markers of regulatory T cells (Treg cells) in the CD4+ T cells of the patients with systemic lupus erythematosus (SLE) in order to reveal the role of Treg cells in the pathogenesis of SLE.

METHODS: Peripheral blood samples were collected from 29 newly diagnosed and treatment-naïve SLE patients, 3 males and 26 females, aged (34 +/- 13), and 24 sex and aged-matched healthy controls. Three-color flow cytometry was used to detect the CD4+CD25+ CD127(low/-) T cells, CD4+CD25high T cells, and CD4+CD25+FOXP3+ T cells. The serum anti-nuclear antibody (ANA), anti-ds-DNA antibody, anti-smooth muscle antibody, anti-nucleosome antibody, anti-C1q, C3, and C4 were detected. Blood and urine routine examinations were conducted.

RESULTS: The proportion of blood CD4+ CD25+CD127(low/-) T cells of the SLE patients was not significantly different from that of the controls (P > 0.05), however, the proportions of CD4+CD25+FOXP3+ T cells and CD4+CD25high T cells of the SLE patients were 2.1 +/- 1.2 and 0.8 +/- 0.4 respectively, both significantly lower than those of the controls (4.0 +/- 1.4 and 1.8 +/- 0.8 respectively, both P <0.01). The ratios of the CD4+CD25+CD127(low/-) T cells, CD4+CD25high T cells, and CD4+CD25+FOXP3+ T cells to the CD4+CD25+ T cells of the SLE patients were 0.5 +/- 0.1, 0.1 +/- 0, and 0.3 +/- 0.1 respectively, all significantly lower than those of the controls (0.6 +/- 0.1, 0.2 +/- 0.1, and 0.5 +/- 0. respectively, all P <0.01). The level of CD4+CD25+CD127(low/-) T cell was positively correlated with the levels of CD4+CD25+FOXP3+ T cells and CD4+CD25high T cell (both P < 0.01). The levels of these 3 kinds of cells and their ratios to CD4+CD25+ T cells had no correlation with age, sex, course, IgG, IgA, IgM, urine protein, TIPU, anti-dsDNA, anti-C1q, anti-nuclear body antibody (all P > 0.05), however, were significantly associated negatively with SLE disease activity index, P < 0.05). Only the CD4+CD25+CD127(low/-) T cells/ CD4+CD25+ T cells was negatively correlated with C4 (P <0.01).

CONCLUSION: The relative ratio of Treg cells to the activated CD4+ T cells may play an important role in the pathogenesis of SLE.