Anti-Lipoprotein Lipase Antibody in Systemic Sclerosis: Association with Elevated Serum Triglyceride Concentrations

MASANARI KODERA, IKUKO HAYAKAWA, KAZUHIRO KOMURA, KOICHI YANABA, MINORU HASEGAWA, KAZUHIKO TAKEHARA, and SHINICHI SATO

ABSTRACT.

Objective. The vascular damage systemic sclerosis (SSc) consists mainly of microvascular changes, but recently macrovascular changes with dyslipidemia were recognized. In systemic lupus erythematosus (SLE), autoantibody to lipoprotein lipase (LPL), a key enzyme that hydrolyzes triglycerides, suggested a role of autoimmunity for elevated serum triglyceride levels and atherosclerosis. We investigated the prevalence and levels of anti-LPL antibodies, their clinical correlation, and their functional significance in patients with SSc.

Methods. Serum samples from patients with diffuse cutaneous SSc (dSSc; n = 55), limited cutaneous SSc (lSSc; n = 75), SLE (n = 21), and dermatomyositis (DM; n = 21) and healthy controls (n = 41) were examined by ELISA. The presence of anti-LPL antibody was evaluated by immunoblotting analysis using purified LPL. To determine the functional relevance of anti-LPL antibody in vivo, we assessed whether anti-LPL autoantibody was able to inhibit LPL activity using the LPL activity kit.

Results. ELISA revealed that IgG or IgM anti-LPL antibodies were detected in 35% of SSc patients, while they were also positive in 67% of SLE patients and 43% of DM patients. The presence of IgG anti-LPL antibody was associated with elevated serum triglyceride levels, greater extent of skin fibrosis, and more frequent presence of lung fibrosis, heart involvement, and anti-topoisomerase I antibodies. The presence of anti-LPL autoantibody was confirmed by immunoblotting analysis. LPL activity was inhibited by IgG anti-LPL antibodies in sera from SSc patients with elevated serum triglyceride levels.

Conclusion. Our results suggest that anti-LPL autoantibody contributes to elevated serum triglyceride levels by inhibiting LPL enzyme activity in patients with SSc. (J Rheumatol 2005;32:629-36)

Key Indexing Terms:

SYSTEMIC SCLEROSIS
AUTOANTIBODY
LIPOPROTEIN LIPASE
TRIGLYCERIDE

---

From the Department of Dermatology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan.

M. Kodera, MD; I. Hayakawa, MD, PhD; K. Komura, MD, PhD; K. Yanaba, MD, PhD; M. Hasegawa, MD, PhD; K. Takehara, MD, PhD, Professor; S. Sato, MD, PhD, Associate Professor.

Address reprint requests to Dr. S. Sato, Department of Dermatology, Kanazawa University Graduate School of Medical Science, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8641, Japan. E-mail: s-sato@med.kanazawa-u.ac.jp

Submitted February 23, 2004; revision accepted November 29, 2004.

---