Increased serum levels of N(epsilon)-(hexanoyl)lysine, a new marker of oxidative stress, in systemic sclerosis.
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.
Shimizu
Kazuhiro
K
Department of Dermatology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Ogawa
Fumihide
F
Akiyama
Yuichiro
Y
Muroi
Eiji
E
Yoshizaki
Ayumi
A
Iwata
Yohei
Y
Komura
Kazuhiro
K
Bae
Sangjae
S
Sato
Shinichi
S
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*
D015415:Biomarkers; D007074:Immunoglobulin G; C120589:N(epsilon)-hexanoyllysine; C064155:agalactosyl IGG; D012217:Rheumatoid Factor; D008239:Lysine