These cells, together with those of the gingival epithelium, secrete cytokines such as interleukin (IL)-1β, IL-6, tumour necrosis factor α (TNF-α), and adhesion molecules such as endoglin and intercellular adhesion molecule 1 (ICAM-1), which increase the adhesion of PMNs and monocytes to endothelial cells and increase the permeability of the gingival capillaries, which leads to the accumulation of leukocytes in the infection zone [9]. The gene discussed is ICAM1; the disease is infection.