Histamine receptors on human monocyte-derived dendritic cells -: Immunologic and chemotactic effects

Background: The T-cell stimulatory capacity of dendritic cells (DC) critically depends on inflammatory stimuli during their maturation. Histamine is an important mediator in allergic reactions and might influence DC activity and therefore the cellular infiltrate found in allergic diseases such as atopic dermatitis. Methods: Expression of histamine receptors (HR) on monocyte derived dendritic cells (MoDC) was studied by RT-PCR and flow cytometry. Furthermore, immunologic and chemotactic effects of histamine on MoDC were investigated. Results: MoDC express all four histamine receptors (H1R, H2R, H3R, H4R). Stimulation of MoDC with histamine resulted in cAMP production, downregulation of IL-12p70 production of prestimulated MoDC, and increased IL-10 and IL-16 production. Furthermore, histamine induced chemotactic migration in MoDC via H2R and H3/4R. Conclusion: MoDC express histamine H1-, H2-, H3- and H4-receptors and respond to histamine stimulation with immunologic and chemotactic effects. Therefore, histamine might represent a link between immediate type hypersensitivity reactions and cellular inflammation in allergic disease, e. g., in atopic dermatitis.