Increased beta 2 defensin in recurrent aphthous ulcer

Objectives It was hypothesized that beta 2 defensin (BD‐2) is increased in RAU lesions compared with healthy controls to promote anti‐microbial host defence. Methods RAU and control mucosa samples were subjected to quantitative real‐time PCR and immunostained for BD‐2, CD68, mast cell tryptase and 4‐hydroxynonenal (4HNE). The effect of tumour necrosis factor‐α (TNF‐α) ± interleukin‐17C (IL‐17C), without and with vitamin K3, was studied on BD‐2 expression in epithelial SCC‐25 cells. Results Although BD‐2 mRNA did not differ between healthy and RAU mucosa, BD‐2 stained strongly in acute‐phase RAU epithelium (P = 0.001). In controls, subepithelial BD‐2+ cells were mast cells and macrophages, whereas in RAU, most infiltrating leucocytes were BD‐2+ (P = 0.004). In cell culture, BD‐2 was increased 124‐fold by TNF‐α (P