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BioMed Research International
Volume 2014 (2014), Article ID 231036, 14 pages
Clinical Study

Circulating Conventional and Plasmacytoid Dendritic Cell Subsets Display Distinct Kinetics during In Vivo Repeated Allergen Skin Challenges in Atopic Subjects

17th Respiratory Department and Asthma Centre, Athens Chest Hospital, Athens 11527, Greece
2Cellular Immunology Laboratory, Division of Cell Biology, Center for Basic Research, Foundation for Biomedical Research of the Academy of Athens, Athens 11527, Greece

Received 18 February 2014; Accepted 5 April 2014; Published 28 April 2014

Academic Editor: Petros Bakakos

Copyright © 2014 Stelios Vittorakis et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Upon allergen challenge, DC subsets are recruited to target sites under the influence of chemotactic agents; however, details pertinent to their trafficking remain largely unknown. We investigated the kinetic profiles of blood and skin-infiltrating DC subsets in twelve atopic subjects receiving six weekly intradermal allergen and diluent injections. The role of activin-A, a cytokine induced in allergic and tissue repair processes, on the chemotactic profiles of DC subsets was also examined. Plasmacytoid (pDCs) and conventional DCs (cDCs) were evaluated at various time-points in the blood and skin. In situ activin-A expression was assessed in the skin and its effects on chemokine receptor expression of isolated cDCs were investigated. Blood pDCs were reduced 1 h after challenge, while cDCs decreased gradually within 24 h. Skin cDCs increased significantly 24 h after the first challenge, inversely correlating with blood cDCs. Activin-A in the skin increased 24 h after the first allergen challenge and correlated with infiltrating cDCs. Activin-A increased the CCR10/CCR4 expression ratio in cultured human cDCs. DC subsets demonstrate distinct kinetic profiles in the blood and skin especially during acute allergic inflammation, pointing to disparate roles depending on each phase of the inflammatory response. The effects of activin-A on modulating the chemotactic profile of cDCs suggest it may be a plausible therapeutic target for allergic diseases.