Identifizierung von CD11c⁺ myeloiden dendritischen zellen in adenoiden und in der nasenschleimhaut von gesunden und allergikern

Background: Dendritic cells form a link between innate and acquired immunity. They are capable to detect pathogens based on the recognition of pathogen-associated microbial molecules and trigger the appropriate type of immune responses. In humans, three major subsets of dendritic cells can be distinguished, Langerhans cells of the skin, myeloid DC (MDC) and plasmacytoid DC (PDC). It was reported that PDC infiltrate nasal mucosa in allergen-induced rhinits. Information about the role of MDC in nasal mucosa and the corresponding mucosa-associated lymphoid tissue, the nasopharyngeal adenoids, is limited. Patients and Methods: Here we examined the presence of MDC in adenoids and in nasal mucosa of healthy individuals (n = 9) and in patients with allergic rhinits. MDC were detected by flow cytometry by positive staining for MHC 11 and CD11c and the lack of lineage markers. Dead cells were excluded from analysis. Results: In adenoids, 0.4% of all cells were MDC. Considerable numbers of MDC could also be detected in nasal mucosa. No difference was found between healthy individuals and patients with allergies (0.3% vs. 0.45% MDC: p = 0.12). Interestingly, MDC were absent in patients who received treatment with glucocorticoids, while very high numbers of MDC were found in patients who recently had upper respiratory tract infections. Conclusion: Our results demonstrate for the first time the presence of MDC in nasal mucosa. MDC numbers were similar in healthy individuals and in patients with allergy. This study forms the basis for examining the role of MDC in the pathogenesis of allergic rhinitis, and for the modulation of MDC functional activity with microbial molecules such as CpG oligonucleotides.