FcεRI levels and frequencies of peripheral blood dendritic cell populations in allergic rhinitis

The dendritic cell (DC) lineage encompasses a diverse population of cells with unique subtype-specific functions. In peripheral blood, four DC subsets have been identified based on their distinct expression of CD1c, CD141, CD16, and CD123, and these subpopulations exhibit functional properties in immune responses. However, their respective roles in allergic diseases, such as rhinitis, are unclear. In this study, we have performed comparative assessments of DC subset frequencies and investigated their Fc epsilon RI expression levels in patients with allergic rhinitis. We demonstrate that the frequencies of CD1c(+) and CD141(+) DCs are elevated in grass pollen-allergic subjects compared with healthy controls, irrespectively of allergen stimulation. Among the DC subsets, CD1c(+) DCs expressed the highest levels of Fc epsilon RI mRNA, and a large proportion expressed surface Fc epsilon RI. Furthermore, the Fc epsilon RI expression levels were augmented upon allergen challenge. Thus our data suggest that CD1c(+) DCs influence allergen-specific immune responses. Research on their functional properties in allergy is warranted for development of future immunotherapies targeting specialized DC subsets. (C) 2010 Published by Elsevier Inc. on behalf of American Society for Histocompatibility and immunogenetics.