1. ¹Department of Medical Research, China Medical University Hospital, Taichung, Taiwan, Republic of China
2. ²Graduate Institute of Acupuncture Science, College of Chinese Medicine, China Medical University, Taichung, Taiwan, Republic of China
3. ³Department of Biotechnology and Bioinformatics, Asia University, Taichung, Taiwan, Republic of China
4. ⁴Graduate Institute of Chinese Medical Science, College of Chinese Medicine, China Medical University, Taichung, Taiwan, Republic of China
5. ⁵Division of Immunology and Rheumatology, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan, Republic of China
6. ⁶Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, Republic of China
7. ⁷Department of Biological Science and Technology, China Medical University, Taichung, Taiwan, Republic of China

Correspondence: Dr F-J Tsai, Department of Medical Research, China Medical University Hospital, No. 2 Yuh Der Road, Taichung, Taiwan, Republic of China. E-mail: d0704@www.cmuh.org.tw

⁸These authors should be regarded as joint first authors.

Received 8 November 2006; Accepted 1 February 2007; Published online 15 March 2007.

Abstract

Interleukin (IL)-18, an important mediator of innate and adaptive immunity, plays multiple roles in chronic inflammation, in autoimmune diseases, in a variety of cancers and in number of infectious diseases. IL-18 promoter polymorphisms have been also noted associated with various inflammatory diseases. We investigated the association of IL-18 promoter polymorphisms (-656T/G, -607A/C and -137C/G) with systemic lupus erythematosus (SLE) in Taiwan Chinese patients and controls. Six haplotypes (hts) were identified from the three promoter polymorphisms. The genotype distribution of the ht1 (GCC), ht2 (TAC), ht4 (GAC) and ht5 (TCC) were different in patients and controls (P<0.002). Moreover, the haplotype and genotype frequencies of ht1 were significantly increased in patients with discoid rash (P=0.045, odds ratio (OR): 2.01, 95% confidence interval (CI): 1.01–4.00; P=0.027, OR: 5.13, 95% CI: 1.41–18.68). In addition, the homozygous genotype ht1/ht1 was significant increased in patients with serositis (P=0.015, OR: 9.78, 95% CI: 1.55–61.73). These observations suggest that the three promoter polymorphisms contribute to the genetic background of SLE pathogenesis.