Elevated Neutrophil Elastase in Tears of Ocular Graft-Versus-Host Disease Patients

Abstract

To investigate the levels of neutrophil elastase (NE), matrix metalloproteinases (MMPs), and myeloperoxidase (MPO) in tear washes of patients with ocular graft-vs-host disease (oGVHD). Case-control study. Based on established criteria, oGVHD patients (n= 14; 28 eyes) and age-/sex-matched healthy controls (n= 14; 28 eyes) were enrolled. Tear washes were collected and analyzed for NE using a single-analyte enzyme-linked immunosorbent assay (ELISA). MMPs (1, 2, 3, 7, 8, 9, 12), MPO, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 were analyzed using multianalyte bead-based ELISA assays. Total MMP activity was measured using a fluorimetric assay. Correlation studies were performed between NE, MMP-8, MMP-9, and MPO within study groups. NE, MMP-8, MMP-9, and MPO levels were elevated in oGVHD tears when compared with controls (P < .0001). NE was the most elevated analyte. MMP activity was higher and TIMP-1 levels were lower in oGVHD than in control (P < .0001). In oGVHD, NE significantly correlated with MMP-8 (r= 0.92), MMP-9 (r= 0.90), and MPO (r= 0.79) (P < .0001). MMP-8 correlated with MMP-9 (r= 0.96, P < .0001), and MPO (r= 0.60, P= .001). MMP-9 correlated with MPO (r= 0.55, P= .002). In controls, NE, MMP-9, and MPO significantly correlated with each other (P < .0001). The marked increase in NE in oGVHD tears that correlated strongly with elevated MMP-8, MMP-9, and MPO suggests a common neutrophilic source and provides evidence of neutrophil activity on the ocular surface of oGVHD patients.