title: Endemic pemphigus foliaceus (fogo selvagem) and pemphigus vulgaris: immunoglobulin G heterogeneity detected by indirect immunofluorescence.
abstract: Pemphigus are autoimmune intraepidermal blistering diseases in which immunoglobulin G (IgG) autoantibodies are directed against desmosomal glycoproteins. The aim of this study was to determine the IgG subclass profile of endemic pemphigus foliaceus (fogo selvagem) and pemphigus vulgaris utilizing indirect immunofluorescence.
  
  
  METHODS
  Twenty-five patients with pemphigus vulgaris, 25 with endemic pemphigus foliaceus (fogo selvagem), and 25 healthy controls were analyzed by indirect immunofluorescence for circulating autoantibodies (total IgG and its subclasses).
  
  
  RESULTS
  Our data revealed a significant correlation (P <.05) of disease activity and autoantibody levels in both forms of pemphigus, i.e., negative titers related to clinical remission, whereas positive results related to active disease. Immunoglobulin G subclass analysis in fogo selvagem demonstrated that in patients in remission, 56% showed positive immunoglobulin G4; in active disease, immunoglobulin G4 was the predominant subclass (100% positive in all cases). The IgG subclass profile in pemphigus vulgaris showed that in patients in remission, only 10% were positive for immunoglobulin G4; in active disease, positivity for immunoglobulin G4 was present in 78% to 88% of the cases.
  
  
  CONCLUSIONS
  Subclass characterization of immunoglobulin G autoantibodies is a useful tool for pemphigus follow-up, since immunoglobulin G4 (IgG4) is the subclass that is closely related to recognition of pathogenic epitopes, and consequently with disease activity. Careful monitoring should be performed for fogo selvagem in clinical remission with a homogeneous IgG4 response, since this may indicate more frequent relapses.
authors.affiliation: Department of Dermatology and Immunodermatopathology Laboratory, Hospital das Clínicas, Faculty of Medicine, University of São Paulo - São Paulo/SP, Brazil. valaoki@hotmail.com
authors.forename: Valéria
authors.initials: V
authors.lastname: Aoki
authors.forename: Milian H T
authors.initials: MH
authors.lastname: Huang
authors.forename: Alexandre M
authors.initials: AM
authors.lastname: Périgo
authors.forename: Lígia M I
authors.initials: LM
authors.lastname: Fukumori
authors.forename: Celina W
authors.initials: CW
authors.lastname: Maruta
authors.forename: Claudia G
authors.initials: CG
authors.lastname: Santi
authors.forename: Zilda N P
authors.initials: ZN
authors.lastname: Oliveira
authors.forename: Evandro
authors.initials: E
authors.lastname: Rivitti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D051182:Desmogleins / Q000276:immunology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010392:Pemphigus / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D051182:Desmogleins; D007074:Immunoglobulin G