Human dendritic cell 1 and dendritic cell 2 subsets express FcεRI: Correlation with serum IgE and allergic asthma

Abstract

Background Type 1 dendritic cells (DC1) express the high-affinity IgE receptor (FcεRI); however, the regulation of FcεRI expression by DCs is not well understood. Type 2 DC (DC2) expression of FcεRI has not been demonstrated. Objective We hypothesized that DC2 cellsalso express FcεRI and that expression of FcεRI by the DC1 and DC2 subsets correlates with serum IgE and allergic asthma disease status. Methods To test these hypotheses, we quantitated FcεRI α chain expression by the peripheral blood precursor DC1 (pDC1) and pDC2 subsets by using flow cytometry. Results FcεRI was expressed by the pDC1 and pDC2 subsets, as well as tissue DCs from tonsils. Relative FcεRI expression by basophil, pDC1, and pDC2 subsets was 12:6.5:1, respectively. In both pDC subsets, FcεRI expression was significantly greater in allergic asthmatic subjects than in nonatopic control subjects. pDC1 and pDC2 expression of FcεRI was highly correlated to serum IgE concentration. The pDC1, pDC2, and basophil subsets demonstrated a similar magnitude of increase in FcεRI expression relative to changes in serum IgE. Conclusions FcεRI expression is characteristic of both the DC1 and DC2 subsets. Furthermore, FcεRI expression by these cells is highly correlated to serum IgE and to basophil FcεRI expression and is greater in subjects with allergic asthma. These data support the concept that novel therapeutic approaches directly targeted at FcεRI expression would affect both the sensitization and the effector phases of the allergen-specific immune response.