Leukostasis, leading to microvessel occlusion and increased adherence of leukocytes to the surface of the retinal vascular endothelium secondary to the overexpression of β2-integrin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, has been found in studies both in people with diabetes and in animals with iatrogenically induced diabetes [26]. The gene discussed is ICAM1; the disease is diabetes mellitus.