title: Increased levels of IgA antibodies to cytokeratin-18 and epidermal keratin in rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate whether levels of antibodies to cytokeratin-18 (CK-18) and epidermal keratin (EPK) were raised in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  We measured antibodies to CK-18 and EPK in patients with RA and in patients with osteoarthritis (OA), as well as in normal control subjects by means of an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  IgA antibodies to both CK-18 and EPK were significantly increased in patients with RA compared with the controls and with patients with OA (P < 0.0001). No difference was noted in the levels of IgG or IgM antibodies to CK-18 or EPK between controls and patients with OA or RA.
  
  
  CONCLUSIONS
  Raised levels of IgA autoantibody to CK-18 and EPK may reflect damage to cytokeratin-containing cells (e.g., in synovial endothelium) and could be a useful disease marker in RA.
authors.affiliation: Staffordshire Rheumatology Centre, Stoke-On-Trent, United Kingdom.
authors.forename: A A
authors.initials: AA
authors.lastname: Borg
authors.forename: P T
authors.initials: PT
authors.lastname: Dawes
authors.forename: D L
authors.initials: DL
authors.lastname: Mattey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis*; D004730:Endothelium, Vascular / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D007633:Keratins / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012867:Skin / Q000737:chemistry
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D007633:Keratins