title: Increased production of serum IgA-class antibody to lipid A in Kawasaki disease.
abstract: BACKGROUND
  The etiology of Kawasaki disease (KD) remains unknown. To investigate whether a conventional bacterial antigen is involved in the pathogenesis of KD, we studied the serum response to lipopolysaccharide (LPS).
  
  
  METHODS
  We measured the serum levels of IgG-, IgM- and IgA-class antibodies (Ab) to lipid A, a toxic site of LPS, using enzyme-linked immunosorbent assay in 20 patients with KD, 11 patients with Gram-negative bacterial infection (GNBI), 27 healthy children and 12 healthy adults.
  
  
  RESULTS
  The serum levels of anti-lipid A IgG, IgM and IgA tended to increase with advancing age in healthy children older than 6 months of age. The mean level of anti-lipid A IgM in the acute phase of GNBI and the mean levels of anti-lipid A IgM and IgA in the acute phase of KD were found to increase significantly, in comparison to the age-matched controls. Furthermore, the mean level of anti-lipid A IgA also showed a significant increase from the acute to the subacute phases of KD. Regarding the IgA-subclass response, higher titers of anti-lipid A specific Ab were seen in the IgA2 subclass than in the IgA1 subclass.
  
  
  CONCLUSIONS
  These findings indicate that KD patients demonstrate an intense response to lipid A in the IgA, especially IgA2-subclass, thus suggesting that an unusual activation of the mucosal immune response to a ubiquitous antigen derived from Gram-negative bacteria may be involved in the pathogenesis of KD.
authors: Department of Pediatrics, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan. peditake@me.ndmc.ac.jp
authors: Seiichiro
authors: S
authors: Takeshita
authors: Hiroko
authors: H
authors: Kawase
authors: Tooru
authors: T
authors: Shimizu
authors: Maki
authors: M
authors: Yoshida
authors: Isao
authors: I
authors: Sekine
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D007223:Infant; D008050:Lipid A / Q000276:immunology*; D008070:Lipopolysaccharides; D008297:Male; D009080:Mucocutaneous Lymph Node Syndrome / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D008050:Lipid A; D008070:Lipopolysaccharides