Immunolocalization of CD1a expressing dendritic cells in sinonasal polyposis

Sinonasal polyps are benign projections of edematous nasal mucosa lined by respiratory epithelium. Langerhans cells (LCs) belonging to the dendritic cell family located in respiratory epithelium are involved in antigen presentation and maintenance of local immunological homeostasis. This study aims to elucidate the morphology and distribution of CD1a positive LCs in normal nasal mucosa and compare the same with polypoid nasal mucosa by immunohistochemistry. Normal nasal mucosa (n=20) was obtained from patients underwent septoplasty for deviated nasal septum. Polypoid nasal mucosa (n=22) was obtained from patients with chronic rhinosinusitis (CRS) or allergic fungal rhinosinusitis who underwent excision of nasal polyps. The tissue obtained were processed for immunohistochemistry and stained with CD1a-EP80 Rabbit monoclonal antibody. In the tissues studied, CD1a positive LCs were observed in both the epithelium and lamina
propria. Different morphological subtypes of LCs were noted in the epithelium. The cells were distributed adjacent to walls of subepithelial capillaries and cysts. The median number of CD1a positive LCs was significantly higher in polypoid category (13.5 per mm2) as compared with normal nasal mucosa (2.5per mm2) (p=0.001). Presence of CD1a positive LCs in polypoid nasal mucosa hints at a critical immunological role in the etiopathogenesis of nasal polyps.