title: Platelet-activating factor (PAF) induces wheal and flare skin reactions independent of mast cell degranulation.
abstract: BACKGROUND
  Platelet-activating factor (PAF) causes wheal and flare responses which are abrogated by H1-antihistamines giving rise to the hypothesis that PAF-induced wheal development is secondary to histamine release from dermal mast cells. But is this hypothesis correct?
  
  
  METHODS
  Wheal and flare responses were induced by intradermal injection of PAF, codeine and histamine in 14 healthy volunteers. Dermal histamine and PGD2 contractions were measured using microdialysis.
  
  
  RESULTS
  PAF, unlike histamine and codeine, did not cause a statistically significant rise in mean histamine levels with ten persons showing negligible histamine release. Codeine caused a significant but variable histamine release, ranging from 29 to 282 ng/ml. Codeine, but not PAF or histamine, caused a small but statistically significant release of PGD2.
  
  
  CONCLUSIONS
  Wheal and flare reactions in human skin induced by PAF are not associated with histamine release and, therefore, appear to be independent of mast cell degranulation.
authors: Department of Dermatology and Allergy, Allergie-Centrum-Charité, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors: K
authors: K
authors: Krause
authors: A
authors: A
authors: Giménez-Arnau
authors: E
authors: E
authors: Martinez-Escala
authors: M
authors: M
authors: Farré-Albadalejo
authors: M
authors: M
authors: Abajian
authors: M K
authors: MK
authors: Church
authors: M
authors: M
authors: Maurer
mesh_terms: D000328:Adult; D015550:Cell Degranulation / Q000187:drug effects / Q000276:immunology; D003061:Codeine / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D005858:Germany; D006632:Histamine / Q000009:adverse effects / Q000494:pharmacology*; D006636:Histamine Release / Q000187:drug effects*; D006801:Humans; D007271:Injections, Intradermal; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology; D017551:Microdialysis; D010972:Platelet Activating Factor / Q000009:adverse effects / Q000494:pharmacology*; D012016:Reference Values; D012494:Sampling Studies; D012867:Skin / Q000187:drug effects; D012882:Skin Tests / Q000379:methods; D014581:Urticaria / Q000139:chemically induced* / Q000276:immunology; D055815:Young Adult
chemical_list: D010972:Platelet Activating Factor; D006632:Histamine; D003061:Codeine