IgE-positive plasma cells are present in adenoids of atopic children

Conclusions. We demonstrated the presence of IgE+ plasma cells in the adenoids of atopic children. Our data suggest that adenoids are capable of local production of IgE and support the role of adenoids as an inductive site for allergic reactions. Objective. We have previously demonstrated increased numbers of IgE+ cells in the adenoids of atopic children and also found support for an IL-4-induced class switch to IgE production in adenoids. In search of further evidence of adenoids being involved in IgE-mediated sensitization, we investigated the distribution of plasma cells and macrophages positive for IgE in adenoids. Material and methods. Adenoid tissue from atopic and non-atopic children was examined using immunohistochemical markers for IgE, plasma cells (CD138) and macrophages (CD68). The distribution of positive cells was determined in the extrafollicular area and in the follicles of adenoids. Co-localization of IgE and CD138+ plasma cells and CD68+ macrophages was examined using immunohistochemical double-staining methods. Results. Non-atopic adenoids contained no or very few IgE+ cells. In contrast, IgE+ cells were found in high numbers in atopic adenoids, mainly in the extrafollicular area. Higher numbers of IgE+ plasma cells and IgE+ macrophages were also found in the adenoids of atopic children.