Does Novel IL-33 Correlates with TNF- alpha in RA and SLE?

ABSTRACT

Production of high amounts of inflammatory cytokines plays direct role in disease pathogenesis, including that of systemic lupus erythematosus [SLE] and rheumatoid arthritis [RA]. To investigate whether serum levels of novel IL- 33 and TNF- alpha are higher in Egyptian RA and SLE patients than controls and to compare serum levels of the novel IL-33 with TNF- alpha in RA and SLE with assessing their correlation to clinical disease activity and laboratory findings. 24 SLE, 25 RA and 25 controls were enrolled in this study. Disease activity was evaluated using SLEDAI for SLE patients and DAS 28 for RA patients. IL-33 and TNF- alpha serum levels were determined using sandwich enzyme immunoassay. A significant statistical difference of IL-33 level between SLE and RA groups [P=0.002] and between SLE and control groups existed [P<0.001]. However, a non-significant difference existed between RA and control groups [P=0.340]. There was a significant statistical difference of TNF-alpha level between SLE and control groups [P<0.001] and between RA and control groups [P<0.001], which didn't exist between RA and SLE groups [P=0.070]. A significant positive correlation of serum IL-33 level with serum TNF- alpha level in SLE patients occurred [r=0.505, P=0.012], which was not found in RA [r=-0.023, P=0.912] or in the controls [r=-0.168, P=0.601]. A significant positive correlation was found between TNF- alpha level and SLE patients with high disease activity [r=0.446, P=0.029], which didn't exist with IL-33 [r=0.227, P=0.286]. There was no correlation between serum IL- 33 and DAS 28 [r=0.205, P=0.326], however a negative correlation occurred with TNF- alpha [r=-0.404, P=0.045]. Serum levels of TNF- alpha and novel IL-33 were higher in RA and SLE Egyptian patients than controls. A significant positive correlation occurred between serum IL-33 and serum TNF- alpha in SLE but not in RA patients. Most clinical and laboratory variables in RA and SLE patients did not correlate with either serum IL-33 or TNF- alpha levels