title: Pollen grains induce a rapid and biphasic eczematous immune response in atopic eczema patients.
abstract: BACKGROUND
  Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. Yet, the underlying immunological mechanisms are not well understood.
  
  
  METHODS
  To delineate the effect of native pollen grains on human skin of healthy and atopic individuals we performed patch tests (atopy patch test with native pollen grains, PPT). Nickel patch tests (NPT) served as an established model of contact dermatitis. Skin site biopsies were taken 6-96 h after allergen application and investigated immunohistochemically.
  
  
  RESULTS
  Histology of positive patch tests showed an influx of mononuclear cells (predominantly CD4+, CD25+, CD45RO+). This influx was detected earlier in the PPT reaction than in the immune response to nickel. A biphasic cytokine response could be detected in the PPT: IL-5 dominated in the early, IFN-gamma in the late phase. The NPT was continuously dominated by IFN-gamma. Dendritic cell subpopulations imitated the earlier kinetics of the mononuclear infiltrate.
  
  
  CONCLUSIONS
  Thus, pollen grains induce eczematous reactions in susceptible individuals. This reaction appears clinically and immunohistochemically similar to the contact hypersensitivity reaction to nickel but follows a faster kinetic and a biphasic course: Th2 and IgE in the early (24 h) and Th1 predominance in the late (96 h) phase.
authors.affiliation: Division of Environmental Dermatology and Allergy GSF, ZAUM-Center for Allergy and Environment, Technical University, Munich, Germany.
authors.forename: Kilian
authors.initials: K
authors.lastname: Eyerich
authors.forename: Johannes
authors.initials: J
authors.lastname: Huss-Marp
authors.forename: Ulf
authors.initials: U
authors.lastname: Darsow
authors.forename: Andreas
authors.initials: A
authors.lastname: Wollenberg
authors.forename: Stefanie
authors.initials: S
authors.lastname: Foerster
authors.forename: Johannes
authors.initials: J
authors.lastname: Ring
authors.forename: Heidrun
authors.initials: H
authors.lastname: Behrendt
authors.forename: Claudia
authors.initials: C
authors.lastname: Traidl-Hoffmann
mesh_terms: D000485:Allergens / Q000276:immunology*; D029662:Betula / Q000276:immunology; D001706:Biopsy; D015704:CD4 Antigens / Q000032:analysis; D002452:Cell Count; D003876:Dermatitis, Atopic / Q000097:blood / Q000276:immunology* / Q000473:pathology; D002523:Edible Grain / Q000276:immunology*; D005512:Food Hypersensitivity; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000032:analysis / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis; D015848:Interleukin-5 / Q000032:analysis / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000032:analysis; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D009532:Nickel / Q000276:immunology; D010328:Patch Tests; D031784:Phleum / Q000276:immunology; D011058:Pollen / Q000276:immunology*; D012867:Skin / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors
chemical_list: D000485:Allergens; D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D015848:Interleukin-5; D007073:Immunoglobulin E; D009532:Nickel; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens