Functional MMP-9 polymorphisms modulate plasma MMP-9 levels in multiple sclerosis patients.

We have described that MMP-9 C(-1562)T and (CA)(n) polymorphisms contribute to multiple sclerosis (MS). Here, we evaluate whether plasma MMP-9 levels are related to disease severity, drug therapy resistance and polymorphisms. For sub-study 1, 36 patients with MS and 35 controls were recruited. For sub-study 2, 88 individuals (53 patients and 35 controls) were included in a cross-sectional analysis. MS patients presented higher MMP-9 activity (1.4±0.18 versus 0.93±0.18A.U. for control, P<0.05). Drug-therapy resistant individuals exhibited increased MMP-9 activity (1.96±0.25 versus 1.21±0.09A.U. for non-resistant patients). EDSS score was also related to MMP-9 levels. The CT+TT and HH genotypes had higher MMP-9 levels as compared to patients carrying the CC and LL. Drug therapy resistance, disease severity, MMP-9 plasma activity and polymorphisms are associated with MS.