Association between Serum Matrix Metalloproteinase- (MMP-) 3 Levels and Systemic Lupus Erythematosus: A Meta-analysis

INTRODUCTION: Matrix metalloproteinase (MMP) is an emerging disease marker in rheumatic diseases. This is a meta-analysis aimed at systematically reviewing association between serum MMP-3 levels and systematic lupus erythematosus (SLE) activity, which sought to raise interest in MMP-3 as a putative biomarker. METHODS: We conducted a meta-analysis of serum MMP-3 levels in patients with SLE and controls. We performed a PubMed search, EMBASE search, and forward search of the retrieved articles published until Oct. 1, 2018. In addition to this, we included data from a case-control study on a national pediatric SLE cohort, in which serum MMP-3 levels were measured in 11 SLE patients and 9 controls (unpublished). Subgroup analyses based on gender and disease activity were performed. RESULTS: A total of 662 cases and 771 controls including 651 patients and 762 controls from 11 publications were studied. We observed significantly higher MMP-3 levels in SLE patients compared to healthy controls (P < 0.001, Hedges' g: 2.104, 95% CI 1.426-2.782). In subgroup analyses, we found a significant elevation of MMP-3 in the patients with nephritis compared to those without (P = 0.006, Hedges' g: 0.611, 95% CI 0.611-1.704). This finding was consistent between patients with persistent proteinuria and those without (P = 0.023, Hedges' g: 1.535, 95% CI 0.207-2.862). Meta-analysis showed no association between MMP-3 levels and gender or anti-double strand DNA antibody titer. CONCLUSIONS: Our meta-analysis demonstrated significantly higher MMP-3 levels in SLE patients than in controls and in patients with renal involvement than in those without.