<i>MMP9</i> Genotype and Systemic T-Cell Subsets Correlate With Structural and Functional Outcomes in Neovascular Age-Related Macular Degeneration

Purpose: Genetic studies implicate the matrix metalloproteinase-9 (MMP9) locus in neovascular age-related macular degeneration (nvAMD) risk but genotype-phenotype associations of MMP9 with nvAMD are lacking. This study aimed to investigate the influence of MMP9 genotype and T-cell subset frequency on structural and functional treatment outcomes in nvAMD. Methods: We reanalyzed single-cell RNA sequencing data and used ELISA and flow cytometry in THP-1-derived monocytes to measure immune cell expression of MMP9 within human choroids. In a clinical nvAMD cohort of 38 patients, we genotyped the nvAMD risk single nucleotide polymorphism (SNP; rs4810482) and quantified retinal fluid using deep-learning-based optical coherence tomography (OCT) image analysis. On a subset of nine patients, we performed high-dimensional immunophenotyping. Results: MMP9 is predominantly expressed in mature THP-1-derived dendritic-like cells (ELISA, P = 0.009; flow cytometry, P = 0.001). Patients with the TC genotype of MMP9 exhibited greater disease severity compared to CC or TT genotypes with a significantly higher total retinal fluid volume (P = 0.009). Immunophenotyping revealed that higher proportions of circulating CD8+ effector memory T cells re-expressing CD45RA (TEMRA) were associated with increased residual subretinal fluid (P = 0.03), indicating persistent disease activity. Conclusions: MMP9 genotype affects structural and functional outcomes in patients with nvAMD. Along with the observed systemic immune dysregulation, these findings support the role of a MMP9-dendritic-T-cell axis in nvAMD immunopathogenesis and highlight this as a potential therapeutic target.