Lupus (2016) 0, 1–7 http://lup.sagepub.com PAPER Role of MMP-7 in the pathogenesis of systemic lupus erythematosus (SLE) H Vira 1 , V Pradhan 1 , V Umare 1 , A Chaudhary 1 , A Rajadhyksha 2 , M Nadkar 2 , K Ghosh 1 and A Nadkarni 1 1 Department of Clinical and Experimental Immunology, National Institute of Immunohaematology, Mumbai, India; and 2 Department of Medicine, King Edward Memorial Hospital, Mumbai, India Systemic lupus erythematosus (SLE) is a clinically heterogeneous chronic, inflammatory auto- immune disorder. The association of MMP-7 and disease severity is still unclear. A total of 150 SLE patients and matched healthy controls were recruited for this study. Disease activity was scored according to SLEDAI (98 active and 52 inactive disease). Mean serum MMP-7 levels were significantly higher in SLE patients than controls (p < 0.001). Patients with active disease showed higher levels (16.24  6.2 ng/ml) as against inactive disease (10.50  3.97 ng/ml) (p  0.0001). Mean MMP-7 mRNA expression was significantly higher in patients (RQ ¼ 3.16  0.93) as compared to controls (RQ ¼ 2.21  0.89, p ¼ 0.006). A positive correlation between MMP-7 levels, mRNA expression and SLEDAI score was observed (r ¼ 0.563, r ¼ 0.427). The MMP-7 181 G allele was found to be significantly higher among SLE patients (p < 0.0001). A significant association was noted between MMP-7 181 A/G þG/G geno- types with renal (p ¼ 0.0027) and CNS (p ¼ 0.0031) manifestations and anti-dsDNA autoantibodies (p ¼ 0.0312). Serum MMP-7 levels and mRNA expression were elevated in advanced stages of SLE, indicating that MMP-7 is associated with disease activity in SLE. Lupus (2016) 0, 1–7. Key words: Autoantibodies; MMP-7 polymorphism; mRNA expression; India Introduction Systemic lupus erythematosus (SLE) is a complex chronic autoimmune disorder that, despite a large number of studies, has an aetiology that is not completely understood. Among the effects of the inflammatory mediators, the induction of matrix metalloproteinases (MMPs) has been demonstrated. The primary pathological findings in patients with SLE are those of inflammation, vasculitis, immune complex deposition, and vasculopathy. 1,2 MMPs are zinc-dependent enzymes that are involved in many normal biological and patho- logical processes such as inflammation and auto- immunity. 3,4 MMP-7 (Matrilysin 1) is produced in both the tubular and glomerular compartment. It was described to be involved in several types of renal diseases with glomerular involvement, including diabetic nephropathy and X-linked Alport syndrome. 5 It has also been reported that MMP-7 facilitates immune access to the central nervous system (CNS) in experimental autoimmune encephalomyelitis (EAE), which is an induced form of autoimmune disorder resembling multiple scler- osis (MS) in an animal model. 6 Accumulation of Matrilysin (MMP-7) is shown to be involved in the remodelling of elastotic areas in sun-damaged skin. 7 Hence it may play a role in mucosal mani- festations involving a malar/discoid rash induced by sun exposure in SLE. In the present study we tried to investigate the role of MMP-7 in pathogen- esis and disease activity of SLE. Material and methods A total of 150 SLE patients (135 females and 15 males) fulfilling the revised American College of Rheumatology (ACR) classification criteria for SLE (1997) 7 were recruited along with 150 age- and sex-matched healthy controls (132 females and 18 males) without any concurrent infections. Correspondence to: Anita Nadkarni, National Institute of Immunohaematology, Department of Clinical and Experimental Immunology, 13th Floor, NMS Bldg., King Edward Memorial Hospital, Parel, Mumbai 400012, India. Email: anitahnadkarni@yahoo.com Received 18 May 2016; accepted 9 November 2016 ! The Author(s), 2016. Reprints and permissions: http://www.sagepub.co.uk/journalsPermissions.nav 10.1177/0961203316682855