title: Elevated Serum Levels of IL-21 in Kawasaki Disease.
abstract: OBJECTIVE
  The serum level of immunoglobulin (Ig)E has been reported to be elevated in patients with Kawasaki disease (KD). We investigated whether interleukin (IL)-21, rather than IL-4, could be related to elevated serum levels of IgE in KD.
  
  
  METHODS
  Sera from 48 patients with KD and 12 controls with high fever were collected to determine the level of IgE using an immunoassay system and the levels of IL-4 and IL-21 were determined using enzyme-linked immunosorbent assay kits.
  
  
  RESULTS
  The median IL-21 level of KD patients was significantly elevated, at 499.5 pg/mL (range: <62.5-1,544 pg/mL), whereas that of controls was <62.5 pg/mL (<62.5-825 pg/mL; P<0.001). The median IL-4 level of KD patients was not elevated (4.0 pg/mL; 2.1-7.6 pg/mL). The median level of total IgE in KD patients was 58.0 IU/mL (5-1,109 IU/mL). No statistically significant correlation was found between IL-21 and total IgE levels (Spearman's R=0.2; P=0.19).
  
  
  CONCLUSIONS
  Patients with KD have elevated levels of IL-21 in the serum. IL-21 may play a role in the pathogenesis of KD.
authors.affiliation: Department of Pediatrics, Yonsei University Wonju College of Medicine, Wonju Christian Hospital, Wonju, Korea.
authors.forename: Yon Jung
authors.initials: YJ
authors.lastname: Bae
authors.forename: Mi Hyun
authors.initials: MH
authors.lastname: Kim
authors.forename: Hae Yong
authors.initials: HY
authors.lastname: Lee
authors.forename: Young
authors.initials: Y
authors.lastname: Uh
authors.forename: Mee Kyung
authors.initials: MK
authors.lastname: Namgoong
authors.forename: Byung Ho
authors.initials: BH
authors.lastname: Cha
authors.forename: Jin-Kyong
authors.initials: JK
authors.lastname: Chun
keywords: Interleukin-21; immunoglobulin E; mucocutaneous lymph node syndrome