title: Interleukin-1 receptor antagonist in neonates, children and adults, and in patients with pauci- and polyarticular onset juvenile chronic arthritis.
abstract: OBJECTIVE
  The production of interleukin (IL) -1 alpha IL-1 beta and IL-1 receptor antagonist (IL-1ra) by blood mononuclear cells (MNC), as well as the corresponding serum levels of IL-1ra were examined in blood samples from umbilical cords (n = 11), children (n = 40) and adults (n = 20), and in 42 patients with juvenile chronic arthritis (JCA) of the pauci- or polyarticular onset type.
  
  
  RESULTS
  IL-1ra serum levels were found to differ significantly between the three age groups, being higher in neonates (569 pg/ml) than in children (70 pg/ml) and adults (177 pg/ml). IL-1ra production in E. coli lipopolysacharide (LPS) stimulated-cultures of MNC was also significantly higher in neonates (median 2451 pg/ml) than in children (1526 pg/ml), but similar to that in adults (2107 pg/ml). IL-1ra levels in the sera of both subgroups of JCA patients were significantly elevated (median 257 pg/ml), but did not reflect paraclinical or clinical disease parameters. In samples of synovial fluid the IL-1ra levels tended to be fairly high, up to approximately 2 ng/ml, but they did not reflect the serum levels of IL-1ra.
  
  
  CONCLUSIONS
  These findings suggests that the upregulation of IL-1ra production forms part of the immunoregulatory response in JCA patients, and that the insufficient production of IL-1ra is unlikely to contribute to the pathogenesis of JCA.
authors.affiliation: Department of Pediatrics GGK, National University Hospital, Copenhagen, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Müller
authors.forename: M
authors.initials: M
authors.lastname: Zak
authors.forename: S
authors.initials: S
authors.lastname: Nielsen
authors.forename: F K
authors.initials: FK
authors.lastname: Pedersen
authors.forename: P
authors.initials: P
authors.lastname: de Nully
authors.forename: K
authors.initials: K
authors.lastname: Bendtzen
mesh_terms: D000293:Adolescent; D000328:Adult; D001171:Arthritis, Juvenile / Q000097:blood*; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000097:blood; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D012795:Sialoglycoproteins / Q000097:blood*; D013582:Synovial Fluid / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins