The correlation analysis of GVHD patients showed positive correlations between MMP-9 and conjunctival staining (rho = 0.55, p ≤ 0.001), and between MMP-9 and OSDI score (rho = 0.3, p=0.01); moreover, it showed a weak inverse correlation between MMP-9 and Schirmer test I (rho = −0.25, p=0.04). This evidence concerns the gene MMP9 and graft versus host disease.