Increased IL-18 in patients with systemic lupus erythematosus: relations with Th-1, Th-2, pro-inflammatory cytokines and disease activity. IL-18 is a marker of disease activity but does not correlate with pro-inflammatory cytokines.
OBJECTIVE
The aim of this study was to investigate the imbalance between Th-1 and Th-2 cytokines in systemic lupus erythematosus patients (SLE) and to asses if any of these cytokines could be related to disease activity.


METHODS
Twenty SLE patients and 20 healthy individuals were investigated. Blood samples were collected to evaluate, using ELISA method, serum levels of a wide array of cytokines including: Th-1 type cytokines (Interleukin (IL)-12, Interferon (IFN)-gamma), Th-2 cytokines (IL-4, IL-10), pro-inflammatory cytokines (tumor necrosis factor (TNF)-alpha, IL-1beta and IL-18). Disease activity was assessed using the SLE Disease Activity Index (SLEDAI). Data were evaluated using the Mann-Whitney and Spearman's rank tests.


RESULTS
The SLE patients group had a higher IL-4, IL-10, IL-12 and IL-18 serum concentration compared to the normal control group. IL-18 was negatively correlated with IL-4 and positively correlated with IFN-gamma. No serum cytokine level was correlated with disease activity except for IL-18, which was found strongly correlated with "active disease", defined as SLEDAI > 8 points. IL-18 showed no correlation with pro-inflammatory cytokines.


CONCLUSIONS
Our results show that Th-1 as well Th-2 cytokines can be elevated in SLE patients suggesting that lupus is a complex disease that may be supported by different cytokine patterns in different time-points. Only IL-18 has been found to be disease-activity related. The role of IL-18 in the pathogenesis of SLE might be important through apoptosis-mediating properties.
Amerio
P
P
Department of Immunodermatology, Dermatological Institute-IRCCS, Rome, Italy. p.amerio@idi.it
Frezzolini
A
A
Abeni
D
D
Teofoli
P
P
Girardelli
C R
CR
De Pità
O
O
Puddu
P
P
D000328:Adult; D015415:Biomarkers / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood; D020382:Interleukin-18 / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D018417:Th1 Cells / Q000378:metabolism*; D018418:Th2 Cells / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D015415:Biomarkers; D020382:Interleukin-18; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma