Identification and immunolocalization of the innate immune receptor CD14 in hypertrophic adenoids and tonsils

The purpose of this study is to determine the expression of CD14 as a marker of the innate immunity in hypertrophic adenoids and tonsils. Twenty-four pediatric patients (age <12 years) with obstructive adenotonsillar hypertrophy, confirmed by sleep study were included in this study. Intensity and expression of positive CD14 infiltrating cells was assessed by immunohistochemistry in specific histologic areas. In tonsils, CD14 immunoreactivity was demonstrated in intraepithelial lymphocytes located in the basal layer of the stratified squamous mucoepithelium. CD14 expression was significantly higher in mucosal layers and inter-follicular areas of tonsils than adenoid tissues [(p < 0.001), (p = 0.021), respectively]. CD14 expression was significantly higher in the submucosal layers of adenoids than tonsil tissues (p = 0.002). Hypertrophic adenoids and tonsils from children with OSA are prominent sites of innate defense, with over expression of CD14. The enhanced expressions of CD14 cells in adenoids and tonsils may be an important factor for the development and persistence of adenoids and tonsils enlargement causing OSA in children. CD14 expression in adenoids and tonsils illustrates an important immunological sentinel function of the innate immunity of the upper airway.