title: Anti-keratin antibodies in patients with juvenile idiopathic arthritis.
abstract: OBJECTIVE
  We discuss the presence of anti-keratin antibodies (AKA) of the IgG class in patients with defined juvenile idiopathic arthritis (JIA).
  
  
  METHODS
  An indirect immunofluorescence test with rat oesophagus substrate was used for the detection and quantification of AKA antibodies in patients'sera.
  
  
  RESULTS
  Overall 30/60 patients with JIA had sera positiveforAKA (50%, p=0.0005) ranging from 1:20 to 1:160 dilutions. Using the classification criteria for childhood idiopathic arthritis, AKA occurred in 2/7 patients with systemic disease (28.6%), in 13/30 patients with RF negative polyarthritis (43.3%, p=0.008) and in 12/18 RF positive polyarthritis (66.7%, p=0.002). AKA were also found in a small cohort of patients with oligoarthritis (1/3) and psoriatic arthritis (2/2). AKA positivity occurred in 3/26 healthy controls at a 1:20 dilution. The presence ofAKA was correlated as well as with the severity of the disease. Our study revealed that AKA was present overall in 16/29 patients (55.2%) with severe JIA and in 11/26 patients (42.3%) with non-severe disease. We also observed that AKA remained positive regardless of disease activity. AKA were detectable in 44.4% patients with active JIA and in 45.9% patients in the complete or near remission.
  
  
  CONCLUSIONS
  Our data suggest that AKA are present in patients with JIA. However no correlation with severity or disease activity was observed.
authors.affiliation: 2nd Paediatric Clinic, University Hospital Motol, Prague, Czech Republic. ilona.hromadnikova@lfmotol.cuni.cz
authors.forename: I
authors.initials: I
authors.lastname: Hromadníková
authors.forename: P
authors.initials: P
authors.lastname: Vavrincova
authors.forename: K
authors.initials: K
authors.lastname: Stechova
authors.forename: D
authors.initials: D
authors.lastname: Hridelova
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001171:Arthritis, Juvenile / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D066298:In Vitro Techniques; D007633:Keratins / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D051381:Rats; D012217:Rheumatoid Factor / Q000097:blood
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D007633:Keratins; D012217:Rheumatoid Factor