Elevation of plasma interleukin-18 concentration is correlated with disease activity in systemic lupus erythematosus.
BACKGROUND
Previous studies have indicated that the autoimmune phenomenon might be caused by an imbalance of T-helper cell (Th) cytokines.


METHODS
We investigated the plasma concentrations of a novel pro-inflammatory Th1 cytokine, interleukin (IL)-18, and its inducer, IL-12, in patients with systemic lupus erythematosus (SLE) and correlated them with the SLE disease activity index (SLEDAI). Plasma IL-18 and IL-12 concentrations of 40 SLE patients and 18 sex- and age-matched control subjects were measured by enzyme-linked immunosorbent assay.


RESULTS
Plasma IL-18 and IL-12 concentrations were significantly higher in SLE patients than in control subjects [median (interquartile range): IL-18, 320.0 pg/ml (164.4-475.6 pg/ml) vs 130.1 pg/ml (57.8-202.4 pg/ml), P<0.001; IL-12, 143.3 pg/ml (39.4-247.2 pg/ml) vs. 84.7 pg/ml (29.3-140.1 pg/ml), P<0.001]. Increases in IL-18 concentration correlated positively and significantly with SLEDAI score (r = 0.449, P = 0.004).


CONCLUSIONS
The novel cytokine IL-18 might play a crucial role in triggering the inflammatory processes in SLE.
Wong
C K
CK
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong, China.
Li
E K
EK
Ho
C Y
CY
Lam
C W
CW
D000293:Adolescent; D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D018664:Interleukin-12 / Q000097:blood; D020382:Interleukin-18 / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D011239:Prednisolone / Q000627:therapeutic use; D012016:Reference Values
D005938:Glucocorticoids; D020382:Interleukin-18; D018664:Interleukin-12; D011239:Prednisolone