title: Autoantibody reactivity in a case of Schnitzler's syndrome: evidence for a Th1-like response and detection of IgG2 anti-FcepsilonRIalpha antibodies.
abstract: Schnitzler's syndrome is a rare disease characterized by chronic urticaria, monoclonal IgM, and clinical and laboratory signs of inflammation. In a subset of patients, the urticarial lesions cause pruritus. However, the pathophysiology of the disease and the biochemical basis of urticaria are not known. We describe a female patient with Schnitzler's syndrome suffering from chronic urticaria associated with pruritus. The patient's serum was found to contain IgG antibodies recognizing cellular components of the microvasculature. In particular, IgG3 antibodies directed against proteins (14-100 kD) expressed in cultured dermal microvascular endothelial cells and mast cells, were found by immunoblotting. Moreover, IgG2 antibodies specific for the alpha-chain of the FcepsilonRI were detectable. However, the autoantibodies did not mediate histamine release in mast cells or basophils. In patients with IgM paraproteinemia who did not have Schnitzler's syndrome, antibodies against endothelial/mast cells or FcepsilonRI were not detectable. In summary, we describe subclass-specific IgG reactivity against microvascular endothelial cells and mast cells indicating Th1 autoimmunity in a patient with Schnitzler's syndrome. Whether such autoantibodies are recurrently produced in patients with Schnitzler's syndrome and play a role in the pathophysiology of the disease remains to be determined.
authors.affiliation: Department of Internal Medicine I, Division of Hematology and Hemostaseology, University of Vienna, Austria. wolfgang.r.sperr@univie.ac.at
authors.forename: W R
authors.initials: WR
authors.lastname: Sperr
authors.forename: S
authors.initials: S
authors.lastname: Natter
authors.forename: M
authors.initials: M
authors.lastname: Baghestanian
authors.forename: J
authors.initials: J
authors.lastname: Smolen
authors.forename: K
authors.initials: K
authors.lastname: Wolff
authors.forename: B R
authors.initials: BR
authors.lastname: Binder
authors.forename: M R
authors.initials: MR
authors.lastname: Müller
authors.forename: K
authors.initials: K
authors.lastname: Lechner
authors.forename: R
authors.initials: R
authors.lastname: Valenta
authors.forename: P
authors.initials: P
authors.lastname: Valent
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D004730:Endothelium, Vascular / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000145:classification / Q000276:immunology*; D008168:Lung / Q000276:immunology / Q000473:pathology; D008407:Mast Cells / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology*; D013577:Syndrome; D018417:Th1 Cells / Q000276:immunology*; D014581:Urticaria / Q000276:immunology* / Q000473:pathology
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D011961:Receptors, Fc