Diabetes-induced increases in ROS production, vascular endothelial growth factor (VEGF) and intercellular adhesion molecule 1 (ICAM1) expression, leukocyte adhesion to the retinal vessels, and breakdown of the blood-retinal barrier were all prevented by deletion of the NADPH oxidase 2 (NOX2) gene [19,21]. The gene discussed is CYBB; the disease is diabetes mellitus.