Increased ratio of Th17 cells to SIGIRR+CD4+ T cells in peripheral blood of patients with SLE is associated with disease activity.

To investigate the clinical significance of the ratio of T helper cell 17 (Th17) cells to single immunoglobulin IL-1-related receptor (SIGIRR)+ cluster of differentiation (CD4)+ T cells in patients with systemic lupus erythematosus (SLE), novel data and data from previous studies were analyzed. The frequency of Th17 cells in peripheral blood mononuclear cells (PBMCs) and their correlation with clinical data were evaluated in 48 patients with SLE and 38 healthy controls through flow cytometry. Compared with healthy controls, the percentage of Th17 cells was significantly increased in the PBMCs of patients with SLE (Z=-5.82, P<0.001). Compared with inactive SLE (ISLE), the percentage of Th17 cells in active SLE (ASLE) were significantly increased (Z=-4.26, P<0.0001). Compared with patients without lupus nephritis, the frequency of Th17 cells was significant increased (Z=-2.20, P=0.028). The frequency of Th17 cells was inversely correlated with the frequency of SIGIRR+CD4+ T cells (r=-0.61, P<0.001). The ratio of Th17 cells to SIGIRR+CD4+ T cells in ASLE was significantly increased compared with healthy controls or patients with ISLE (P<0.001) and was inversely correlated with complement component 3 and complement component 4, and positively correlated with SLE disease activity index and 24-h proteinuria (P<0.05). In summary, increased numbers of Th17 cells and decreased numbers of SIGIRR+CD4+ T cells in patients with SLE suggested that SIGIRR+CD4+ T and Th17 cells may be involved in the pathogenesis of SLE.

The decreased frequency of SIGIRR-positive CD4+ T cells in peripheral blood of patients with SLE and its correlation with disease activity.

Recently, many studies have shown that Single immunoglobulin interleukin-1 receptor related protein (SIGIRR), a member of the IL-1R family acting as a negative regulator of TLR/IL-1R signaling, affects autoimmune responses in animal model of systemic lupus erythematosus (SLE). However, the role of SIGIRR in the pathogenesis of human SLE has not been widely explored. In this study, we analyzed the frequency of SIGIRR-positive CD4+ T cells in peripheral blood mononuclear cells (PBMCs) of SLE patients and its correlation with disease activity as well as the clinical data. Circulating SIGIRR-positive CD4+ T cells were quantified in 51 SLE patients and 38 healthy controls by using flow cytometer. Results showed that the percentages of SIGIRR-positive CD4+ T cells were decreased in the PBMCs of SLE patients compared with healthy controls (Z = -5.49, P < 0.001). The frequency of SIGIRR-positive CD4 + T cells were also significantly decreased in SLE patients with nephritis than those without nephritis (Z = -3.71, P < 0.001). In addition, there was significant correlation between the percentages of SIGIRR-positive CD4+ T cells and SLEDAI score (r s = -0.74, P < 0.001), 24-hour urine protein (r s = -0.62, P < 0.001), Scr (r s = -0.65, P < 0.001), ESR (r s = -0.60, P < 0.001), C3 (r s = 0.53, P < 0.001) as well as C4 (r s = 0.52, P < 0.001). However, there was no correlation between the proportion of SIGIRR-positive CD4+ T cells and glucocorticoid dose (P = 0.59). In summary, decreased numbers of SIGIRR-positive CD4+ T cells in SLE patients and its correlation with SLEDAI score as well as the clinical data suggest that SIGIRR may be involved in the pathogenesis of SLE.