title: Elevated levels of IgG and IgG4 to Malassezia allergens in atopic eczema patients with IgE reactivity to Malassezia.
abstract: BACKGROUND
  The opportunistic yeast Malassezia is considered to be one of the factors that can contribute to atopic eczema (AE). Elevated serum IgE levels, T-cell proliferation and positive skin prick test (SPT) and atopy patch test (APT) reactions to Malassezia are found among AE patients.
  
  
  METHODS
  Sera from 127 AE patients, 14 patients with seborrheic dermatitis (SD) and 33 healthy controls were investigated for IgE and IgG4 to M. sympodialis extract and four recombinant Malassezia allergens; rMala s 1, rMala s 5, rMala s 6, and rMala s 9. In addition, IgG to the recombinant allergens was analyzed. The IgG and IgG4 levels were compared to IgE levels and in vivo reactions (SPT and APT) to Malassezia.
  
  
  RESULTS
  AE patients with serum IgE levels >0.35 kU/l to M. sympodialis extract had significantly higher IgG4 levels to M. sympodialis extract than AE patients without detectable serum IgE to M. sympodialis extract, SD patients and healthy controls. Among the AE patients with and without detectable serum IgE to M. sympodialis extract, respectively, there were no differences in IgG4 levels between patients with positive or negative in vivo reactions to M. sympodialis extract. IgG4 to the rMala s allergens was almost exclusively found among patients with IgE to the same allergen. Within the four tested rMala s allergens, most IgG4 reactions were found to rMala s 6, an allergen with homology to cyclophilin.
  
  
  CONCLUSIONS
  Elevated serum IgG4 to M. sympodialis extract accompanies elevated serum IgE to the extract. This is further confirmed by the association between IgG/IgG4 and IgE to recombinant Malassezia allergens.
authors.affiliation: Department of Medicine, Unit of Clinical Allergy Research, Karolinska Institute and Hospital, Stockholm, Sweden.
authors.forename: Catharina
authors.initials: C
authors.lastname: Johansson
authors.forename: Maria
authors.initials: M
authors.lastname: Tengvall Linder
authors.forename: Rob C
authors.initials: RC
authors.lastname: Aalberse
authors.forename: Annika
authors.initials: A
authors.lastname: Scheynius
mesh_terms: D000293:Adolescent; D000328:Adult; D000908:Antibodies, Fungal / Q000097:blood*; D000946:Antigens, Fungal / Q000276:immunology; D003876:Dermatitis, Atopic / Q000097:blood* / Q000276:immunology*; D003881:Dermatomycoses / Q000097:blood / Q000276:immunology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D008290:Malassezia / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011852:Radioallergosorbent Test; D011994:Recombinant Proteins / Q000276:immunology
chemical_list: D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D007073:Immunoglobulin E