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

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.

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.

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).

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