Human epidermal langerhans cells express the high affinity receptor for immunoglobulin E (FcεRI)

It has been suggested that epidermal Langerhans cells (LC) bearing immunoglobulin E (IgE) may be involved in the genesis of atopic disease. The identity of the IgE receptor(s) on LC remained unclear, although it represents a crucial point in understanding cellular events linked to the binding of allergens to LC via IgE. In this report, we demonstrate that epidermal LC express the high affinity receptor for the Fc fragment of IgE (FcεRI) which has, so far, only been described on mast cells and basophils. Epidermal LC react with antibodies specific for the α subunit of the tetrameric (α,β,2γ) FcεRI. Specific transcripts for FcεRIα and FcεRIγ were detected in LC and correspond to those of human basophils and of the human basophil cell line KU812. Furthermore, human basophils, KU812 cells, and LC express the putative β subunit. Thus human LC express the complete structure of FcεRI. This finding opens new perspectives in the putative functional role of this structure on antigen-presenting cells.