Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disorder that occurs in genetically prone
individuals. Autoimmunity could not be simply explained by Th1/Th2 cell paradigm. T helper 17(Th17) cells
producing the cytokine interleukin-17 (IL-17) may explain the promotion and progression of autoimmune
phenomena. This study aimed to investigate the role of Th17cells, IL-17 and interleukin-23 (IL-23) in the
pathogenesis of SLE and their correlation with disease activity. The frequencies of circulating Th17 cells in
15 patients with active SLE, 15 patients with inactive disease and 15 healthy control subjects were measured
using Flowcytometry after stimulation with phorbol myristate acetate (PMA) and ionomycin for 4 hours.
Serum levels of IL-17 and IL-23 were measured using the enzyme linked immunosorbent assay (EUSA).
Significantly higher mean frequencies of circulating Th17 cells were found in active SLE patients (1.54 t
0.38%, P<0.001) and Inactive SLE patients (1.23t 0.25%, P=0.009) compared to the control group (0.88 t
0.41%). The frequencies of circulating Th17 cells positively correlated with the SLEDAI score (r = 0.812,
P<0.001). The serum levels of IL-17 and IL-23were significantly higher in active SLE (P<0.001) and inactive
SLE patients (P<0.001) than the control group while, serum levels of both cytokines correlated positively with
SLEDAI score (r =0.661, P.< 0.01 and r =0.701, Pc 0.01 respectively). There was significant positive correlation
between the frequency of circulating Th17 cells and plasma levels of IL-17 and IL-23 (r = 0.789, P< 0.001) and
(r = 0.792, P < 0.001) respectively. Results of this study provides evidence of a role of Th17 cells in the
pathogenesis of SLE, and offer scientific rationale for the utility of Th17 cells, IL-17 and IL-23 as biological
markers for SLE disease activity. This would raise the possibility of anti-IL-17 and anti-IL-23 as innovative
therapeutic options in controlling disease activity of SLE. |
