title: Assessment of histamine-releasing activity of sera from patients with chronic urticaria showing positive autologous skin test on human basophils and mast cells.
abstract: BACKGROUND
  All previous studies agree that only a proportion of sera from patients with chronic urticaria (CU) positive on the autologous serum skin test (ASST) are able to induce histamine release in vitro. A non-specific release of bradykinins during clotting of blood samples has been suggested; however, ASST seems rather specific and some data point to the existence of a mast cell-specific histamine-releasing factor.
  
  
  OBJECTIVE
  To assess whether, and to what extent, the use of both human basophils and mast cells increases the sensitivity of in vitro histamine release assays (HRAs) in ASST-positive patients with CU.
  
  
  METHODS
  The histamine-releasing activity of sera from 93 patients with CU selected on the basis of strong skin reactivity on ASST was assessed in vitro on basophils from 1 (n=86), 2 (n=31), or 3 (n=20) normal donors, and on mast cells from 1 (n=3), 2 (n=3), or 3 (n=87) normal donors.
  
  
  RESULTS
  Sera from 88/93 (95%) patients induced significant histamine release from mast cells or basophils on at least one HRA. 76/93 (82%), 45/90 (50%), 22/80 (28%), and 6/12 (50%) sera were able to induce significant histamine release from cells of 2/5, 3/5, 4/5 and 5/5 donors, respectively.
  
  
  CONCLUSIONS
  Sera from nearly all ASST-positive patients with CU are able to induce histamine release in vitro. However, the serum from each single patient seems to show its maximal activity on autologous mast cells in vivo, and functional in vitro tests show much variability and seem less sensitive than ASST in the detection of patients with histamine-releasing factors in their blood.
authors.affiliation: Ambulatorio di Allergologia, Clinica San Carlo, Paderno Dugnano (MI), Italy. r.asero@libero.it
authors.forename: R
authors.initials: R
authors.lastname: Asero
authors.forename: M
authors.initials: M
authors.lastname: Lorini
authors.forename: S U
authors.initials: SU
authors.lastname: Chong
authors.forename: T
authors.initials: T
authors.lastname: Zuberbier
authors.forename: A
authors.initials: A
authors.lastname: Tedeschi
mesh_terms: D000328:Adult; D001491:Basophils / Q000378:metabolism*; D002478:Cells, Cultured; D002908:Chronic Disease; D005260:Female; D006636:Histamine Release; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D044967:Serum / Q000276:immunology; D012882:Skin Tests; D014581:Urticaria / Q000276:immunology*