title: Modulation of serum histamine releasing activity in chronic idiopathic urticaria.
abstract: BACKGROUND
  Sera of about 30% of patients with chronic idiopathic urticaria (CIU) have increased histamine releasing activity (HRA+) on normal basophils. It is not known whether other CIU sera would be HRA+ if a more sensitive histamine release assay was used. Although most HRA+ CIU sera appear to have anti Fc(epsilon)R1 activity, it is not known whether post-binding basophil intracellular events are similar to those after anti-IgE stimulation.
  
  
  RESULTS
  In the presence of D2O, the HR stimulated by 28 previously documented HRA- sera increased from 4+/-0.4 to 21+/-4% with 13 of the 28 sera now considered HRA+. No previous HRA sera was HRA+ with IL-3 treated cells. Histamine release induced by both HRA+ sera and anti-IgE were inhibited by genistein, and Ca2+/Mg2+ depletion but not by bisindoylmaleimide. HRA+ sera induced prominent HR from normal basophils with little surface IgE, but induced no increased HR from basophils unresponsive to anti-IgE.
  
  
  CONCLUSIONS
  Up to 61% of CIU sera will induce increased HR from normal basophils in a sufficiently sensitive assay system. HR induced by most HRA+ sera is more prominent in basophils with very little surface IgE. However, there may be similar post-binding intracellular activation pathways following stimulation by HRA+ sera and anti-IgE.
authors.affiliation: Department of Medicine, University of Pennsylvania Medical Center, Philadelphia, USA.
authors.forename: B
authors.initials: B
authors.lastname: Zweiman
authors.forename: M
authors.initials: M
authors.lastname: Valenzano
authors.forename: P C
authors.initials: PC
authors.lastname: Atkins
mesh_terms: D001491:Basophils / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000097:blood; D002908:Chronic Disease; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006632:Histamine / Q000097:blood*; D006636:Histamine Release / Q000187:drug effects; D006801:Humans; D007073:Immunoglobulin E / Q000502:physiology; D007377:Interleukin-3 / Q000494:pharmacology; D008274:Magnesium / Q000097:blood; D014581:Urticaria / Q000097:blood*
chemical_list: D004791:Enzyme Inhibitors; D007377:Interleukin-3; D007073:Immunoglobulin E; D006632:Histamine; D019833:Genistein; D008274:Magnesium; D002118:Calcium