CD4+ T-cells have a key instructive role in educating dendritic cells in allergy

Background: Dendritic cells (DCs) are central in allergy as regulators of the Th1/Th2 balance. We have recently demonstrated a unique transcriptional profile of DCs in patients with ongoing allergy compared with healthy subjects and shown that crosstalk between DCs and memory T cellsaffects the transcriptional profile of T cells. However, the transcriptional profile of DCs educated by T cells in allergy is unknown. Methods: In the present study, we have examined the transcriptional profiles of DCs after stimulation with grass pollen allergens, Phleumpratense and coculture with autologous CD4+ memory T cellsusing high-density microarray. Protein analysis was performed using flow cytometry and recombinant antibody protein microarrays. Patients with allergic rhinitis and healthy subjects were compared. Results: The results reveal a distinct T-cell-induced DC profile in atopic individuals. Accordingly, about 170 genes were upregulated and 40 genes downregulated. For example, the chemokine receptorCXCR4 and the tumor necrosis factor receptor CD30were upregulated in DCs derived from atopic donors, and this could also be verified at the protein level. Conclusion: We conclude that crosstalk between CD4+ memory T cellsand autologous DCs induces transcriptional reprogramming in DCs. This finding suggests that T cells have a key instructive role in educating DCs in Th2-type responses.