title: Increased serum levels of N(epsilon)-(hexanoyl)lysine, a new marker of oxidative stress, in systemic sclerosis.
abstract: OBJECTIVE
  To determine serum levels of N(epsilon)-(hexanoyl)lysine (HEL), a new marker of oxidative stress, and its clinical association in patients with systemic sclerosis (SSc).
  
  
  METHODS
  Serum HEL levels from 26 patients with limited cutaneous SSc (lSSc), 34 with diffuse cutaneous SSc (dSSc), 20 with systemic lupus erythematosus (SLE), 20 with dermatomyositis (DM), and 40 healthy individuals were examined by enzyme linked immunosorbent assay.
  
  
  RESULTS
  Serum HEL levels were elevated in patients with SSc compared with healthy controls (n = 40) with similar levels between patients with lSSc and dSSc (p < 0.0001). SSc patients with elevated HEL levels had increased serum levels of anti-agalactosyl IgG antibody, rheumatoid factor (RF), and IgM than those with normal HEL levels (p < 0.05). HEL levels correlated positively with anti-agalactosyl IgG antibody (p = 0.013, r = 0.408) and RF titer (p = 0.0028, r = 0.426).
  
  
  CONCLUSIONS
  Our results suggest that oxidative stress may play an important role in immunological abnormalities of SSc, especially in the production of autoantibodies including anti-agalactosyl IgG antibody and RF.
authors.affiliation: Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shimizu
authors.forename: Fumihide
authors.initials: F
authors.lastname: Ogawa
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Akiyama
authors.forename: Eiji
authors.initials: E
authors.lastname: Muroi
authors.forename: Ayumi
authors.initials: A
authors.lastname: Yoshizaki
authors.forename: Yohei
authors.initials: Y
authors.lastname: Iwata
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Komura
authors.forename: Sangjae
authors.initials: S
authors.lastname: Bae
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sato
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008239:Lysine / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D012217:Rheumatoid Factor / Q000097:blood; D012595:Scleroderma, Systemic / Q000276:immunology / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; C120589:N(epsilon)-hexanoyllysine; C064155:agalactosyl IGG; D012217:Rheumatoid Factor; D008239:Lysine