title: Characteristics of histamine-releasing activity in the sera of patients with chronic idiopathic urticaria.
abstract: BACKGROUND
  The serum histamine-releasing activity (HRA) found in a sizable percentage of patients with chronic idiopathic urticaria (CIU) has been partially characterized. However, the variable effect of individual HRA+ sera in basophils of different donors and the relationship of HRA to the clinical course require further investigation.
  
  
  OBJECTIVE
  The study was performed to characterize the HRA found in sera of some members of a sizable group of carefully evaluated patients with CIU.
  
  
  METHODS
  Sera of 70 patients with CIU, evaluated with a standard protocol, were screened for increased HRA. HRA+ sera were fractionated, heated, and tested on unaltered and altered basophils obtained from a panel of normal donors. HRA levels were compared with concomitant clinical manifestations.
  
  
  RESULTS
  HRA+ sera were found in 30% of our patients with CIU, HRA was predominantly in the IgG fraction, sensitive to 56 degrees C heating for 4 hours, and generally reacted more with IgE-stripped basophils. Considerable variation in the degree of response to HRA+ sera in the basophils of different normal subjects did not correlate with the degree of response of these cells to heterologous anti-IgE antiserum. Serum HRA levels were generally much lower when symptoms decreased in these patients with CIU.
  
  
  CONCLUSIONS
  Serum HRA from patients with CIU appears to bind most commonly to the IgE receptor and may be a marker of clinical disease activity. HRA appears in an IgG-containing fraction of the serum and may contain IgE in some cases.
authors.affiliation: Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6057, 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
authors.forename: T
authors.initials: T
authors.lastname: Tanus
authors.forename: J A
authors.initials: JA
authors.lastname: Getsy
mesh_terms: D001491:Basophils / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D014408:Biomarkers, Tumor; D002908:Chronic Disease; D006636:Histamine Release; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008222:Lymphokines / Q000097:blood* / Q000494:pharmacology; D015995:Prevalence; D000090324:Tumor Protein, Translationally-Controlled 1; D014581:Urticaria / Q000097:blood* / Q000209:etiology / Q000276:immunology*
chemical_list: D014408:Biomarkers, Tumor; D008222:Lymphokines; D000090324:Tumor Protein, Translationally-Controlled 1; D007073:Immunoglobulin E