Immunology Letters 164 (2015) 18–24 Contents lists available at ScienceDirect Immunology Letters j our na l ho me page: www.elsevier.com/locate/immlet Association of MMP-9 gene polymorphisms with Behc ¸ et’s disease risk Abir Naouali a,∗ , Wajih Kaabachi a , Kalthoum Tizaoui a , Amira Ben Amor a , Agnès Hamzaoui a,b , Kamel Hamzaoui a a Department of Basic Sciences, Medicine Faculty of Tunis, University Tunis El Manar, Tunis 1007, Tunisia b A. Mami Hospital, Ariana Homeostasis and Cell Dysfunction, UR/12-SP-15, Tunisia a r t i c l e i n f o Article history: Received 8 July 2014 Received in revised form 13 January 2015 Accepted 20 January 2015 Available online 29 January 2015 Keywords: Behc ¸ et’s disease Matrix metalloproteinases-9 Single nucleotide polymorphism a b s t r a c t The human matrix metalloproteinases (MMPs) are importantly involved in aneurysm formation. Since the clinical manifestations in Behc ¸ et disease (BD) include aneurysm formation among major symptoms, polymorphisms in MMP-9 might be associated with BD susceptibility. The aim of the current case–control study was to investigate the association of four single nucleotide polymorphisms (SNPs) in MMP-9 gene: -1562 C/T, 2003 G/A (R668Q), 836 A/G (Q279R) and 1721 C/G (R574P) with BD risk in the Tunisian pop- ulation. The distribution of MMP-9 gene polymorphisms was analyzed by polymerase chain-reaction (PCR) and restriction fragment length polymorphism (RFLP) for 240 BD patients and 288 controls. Our study indicated that the MMP-9 -1562 C/T polymorphism (rs3918242) was not associated with BD risk. We found a significant association of the MMP-9 2003 G/A (rs17577) with an increased susceptibility to BD. However, the MMP-9 1721 C/G polymorphism (rs2250889) had a protective role against the devel- opment of BD. Subgroup analysis based on stratification by gender revealed that the MMP-9 2003 G/A polymorphism was associated with a highly significant BD risk in women’s group (G vs. A: P = 0.0000001). However, the MMP-9 836 A/G polymorphism had a protective role in men’s group (G vs. A: P = 0.00043). The MMP-9 1721 C/G polymorphism was associated with a protective effect in both men and women groups (CG + GG vs. CC: P = 0.04 and P = 0.0002, respectively). The haplotype analysis did not show any association with BD risk. A significant difference in the MMP-9 serum levels were observed in the patient subgroup with ocular lesions manifestations. © 2015 Published by Elsevier B.V. on behalf of European Federation of Immunological Societies. 1. Introduction Behc ¸ et disease (BD) is a multisystemic and inflammatory dis- order [1] Although the pathogenesis of BD remains unclear, it is thought to have an immunologic cause [2]. Immune dysregulation involving T and B cells with hyperactive neutrophils, contribute to BD pathogenesis, in addition to genetic predisposition [3]. It is characterized by an increased proteolytic activity and a chronic degradation of extracellular matrix components such as collagen, elastin, fibronectin and laminin [4]. Matrix metalloproteinases (MMPs) are a family of zinc met- alloendopeptidases that degrade components of the extracellular matrix [5,6]. The human matrix metalloproteinase 9 (MMP-9) is synthesized as a zymogens with a molecular mass of 92 kDa and ∗ Corresponding author. Tel.: +216 97 068 282. E-mail addresses: naouali abir@yahoo.fr (A. Naouali), Kaabachi.wajih@gmail.com (W. Kaabachi), kalthoum.Tizaoui@yahoo.com (K. Tizaoui), emyra benamor@outlook.fr (A.B. Amor), agnes.hamzaoui@rns.tn (A. Hamzaoui), kamel.hamzaoui@gmail.com (K. Hamzaoui). activated by a variety of factors [7–9]. This family of proteases could be categorized into functional groups based on their sub- strate specificity [10]. MMP-9 acts as a pro-inflammatory factor [11] and play diverse roles under both physiologic and pathologic conditions [5,6,12]. The largest member of MMP-9 is expressed by macrophages located at the site of tissue damage and plays an important role in aneurysm formation [13]. MMP-9 seems to be involved in leukocyte trafficking cells [9]. Their expression is known to increase in various autoimmune, inflammatory, malignant and degenerative diseases, but this association does not necessarily imply a functional role in these pathologies [5,6,12]. Recently Pay et al. [14] reported that the matrix MMPs and particularly the MMP- 9 can be used as an activity indicator of Behc ¸ et’s disease [13]. In the same way Hamzaoui et al. [15] reported an increased MMP- 9 and TIMP-1 levels in cerebrospinal fluids of neuro-BD patients. The metalloproteinases activity is regulated at several different levels: in the gene expression and post-transcriptionally [16,17]. Based on the relevance of the MMP-9 in both inflammation and matrix remodeling, it was hypothesized that the genetic variations in the MMP-9 gene could be implicated in BD risk. A number of polymorphisms have previously been investigated for the MMP-9 http://dx.doi.org/10.1016/j.imlet.2015.01.005 0165-2478/© 2015 Published by Elsevier B.V. on behalf of European Federation of Immunological Societies.