Background:  Mucosal dendritic cells (DC) play a crucial role in tolerance induction as seen in mucosal immunotherapy of atopic diseases. Nevertheless little is known about the phenotypical differences of oral and nasal mucosal DC (nmDC). Recently, we could show that oral mucosal myeloid CD1a⁺ DC (omDC) differ from their skin counterparts especially by the expression of high affinity receptor for immunoglobulin E (IgE; FcɛRI). However, expression pattern of FcɛRI and phenotypical characteristics of CD1a⁺ nmDC have not been elucidated in detailed yet.

Methods:  We performed detailed phenotypical comparison of nmDC and omDC of atopic and nonatopic individuals.

Results:  As reported for omDC, FcɛRI on nmDC of atopic donors was elevated and mostly occupied by IgE while FcɛRI was present only in low amounts on nmDC of nonatopic donors. Nevertheless, the highest FcɛRI expression has been observed on omDC. Furthermore, significant amounts of costimulatory molecules CD40, CD80 and CD86 could be detected on nmDC that expressed more CD80 compared with omDC. Moreover, nmDC displayed less major histocompatability complex (MHC) class I and II molecules than omDC. In addition, nmDC expressed more C‐type lectins CD205, CD206 as well as myeloid marker CD11b while omDC displayed increased expression of CD207 and lipopolysaccharide (LPS) receptor CD14.

Conclusion:  Together these data imply that nmDC phenotypical differ from omDC which might result in diverse functional properties and might be of relevance for selecting routes for immunotherapy of atopic diseases. Moreover these data provide a basis for further studies investigating immunological mechanisms underlying mucosal immunotherapy.