Circulating myeloid and plasmacytoid dendritic cells after allergen inhalation in asthmatic subjects

Allergy. 2007 Oct;62(10):1139-45. doi: 10.1111/j.1398-9995.2007.01465.x.


Background: Dendritic cells are key contributors to initiation and maintenance of T-cell immunity to inhaled allergen. The purpose of this study was to enumerate the changes in peripheral blood myeloid (mDCs) and plasmacytoid dendritic cells (pDCs), the DCs expressing chemokine receptor 6 (CCR6) and chemokine receptor 7 (CCR7), following diluent and allergen inhalation in asthmatic subjects.

Methods: Peripheral blood was obtained from 16 allergic asthmatic subjects before and at 0.5, 1, 2, 3, 4, 6, 24, and 48 h after inhaled diluent and allergen challenges. Dendritic cells were enumerated using flow cytometry.

Results: Allergen inhalation significantly reduced mDCs at 6 h (21.3 +/- 2.0 vs 15.0 +/- 1.8/microl blood; P < 0.05) and 24 h (21.5 +/- 3.4 vs 16.4 +/- 2.4/microl blood; P < 0.05) after challenge. Circulating pDCs were significantly lower than baseline up to 24 h after both allergen and diluent challenges. There was a significant efflux of CCR6(+) mDCs from peripheral blood at 6 h and CCR6(+) pDCs at 4 h after allergen challenge, when compared with diluent. There was no difference in the number of circulating CCR7(+) mDCs or pDCs after diluent or allergen challenges.

Conclusions: Peripheral blood mDCs and CCR6(+) mDCs, but not pDCs, are reduced up to 24 h after allergen inhalation. Thus, allergen inhalation causes trafficking of immature CCR6(+) DCs from blood into the airway, while that of the trafficking of the mature CCR7(+) DCs from the airways into the regional lymph nodes probably occurs through the lymphatic system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Allergens
  • Animals
  • Asthma / blood*
  • Asthma / chemically induced
  • Asthma / immunology*
  • Bronchial Provocation Tests / adverse effects
  • Dendritic Cells / immunology*
  • Flow Cytometry
  • Humans
  • Leukocytes / drug effects
  • Leukocytes / metabolism
  • Lymphocyte Count
  • Middle Aged
  • Myeloid Cells / immunology*
  • Protein Transport
  • Receptors, CCR6 / blood
  • Receptors, CCR7 / blood


  • Allergens
  • Receptors, CCR6
  • Receptors, CCR7