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THU0409 Leucine-Rich Alpha2-Glycoprotein is A Useful Biomarker for Monitoring of Disease Activity in Patients with Adult-Onset Still's Disease
  1. Y.-J. Ha1,
  2. E.-J. Kang2,
  3. S.-W. Lee1,
  4. Y.-B. Park1,
  5. S.-K. Lee1,
  6. J.-S. Song3,
  7. S.T. Choi3
  1. 1Division of Rheumatology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul
  2. 2Division of Rheumatology, Department of Internal Medicine, Busan Medical Center, Busan
  3. 3Division of Rheumatology, Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea, Republic Of

Abstract

Background Leucine-rich alpha2-glycoprotein (LRG) is a protein which contains leucine-rich repeats. Though physiologic functions of LRG have not been clearly defined, its expression was up-regulated during neutrophil differentiation and its levels were significantly elevated in some chronic inflammatory diseases such as inflammatory bowel disease.

Objectives Our study aimed to investigate whether serum leucine-rich α2-glycoprotein (LRG) levels are elevated in patients with adult-onset Still's disease (AOSD) and determine their correlation with disease activity parameters.

Methods We enrolled 39 patients with AOSD, 39 patients with rheumatoid arthritis (RA), and 39 controls. Forty-five serum samples from the patients with AOSD were assayed for LRG using enzyme-linked immunosorbent assay. Comprehensive AOSD activity was determined by modified Pouchot score.

Results Serum LRG levels were significantly elevated in patients with AOSD (128.8±40.8 ng/mL) compared to those in patients with RA and in controls (35.9±15.7 ng/mL, p <0.001; 22.4±6.1 ng/mL, p <0.001, respectively). Patients with active AOSD had a significantly higher LRG level than those with inactive disease (141.4±31.3 ng/mL vs 79.8±37.1 ng/mL, p =0.002). Serum LRG levels were positively correlated with C-reactive protein (γ =0.387, p =0.015), lactate dehydrogenase (γ =0.370, p =0.026), and ferritin (γ =0.687, p <0.001) levels, and the modified Pouchot score (γ =0.756, p <0.001). Serum LRG levels decreased significantly after treatment in all 6 patients with active AOSD who had follow-up evaluations (p =0.007). The best cutoff value for LRG to distinguish AOSD from RA was 67.9 ng/mL, with a sensitivity of 92.3% and a specificity of 97.4%.

Conclusions Serum LRG levels were increased in patients with AOSD and were well-correlated with disease activity measures. LRG may be a useful biomarker for distinguishing AOSD from RA and monitoring the disease activity of AOSD.

References

  1. Takahashi N, Takahashi Y, Putnam FW. Periodicity of leucine and tandem repetition of a 24-amino acid segment in the primary structure of leucine-rich alpha 2-glycoprotein of human serum. Proc Natl Acad Sci U S A 1985;82:1906-10.

  2. Serada S, Fujimoto M, Terabe F, Iijima H, Shinzaki S, Matsuzaki S, et al. Serum leucine-rich alpha-2 glycoprotein is a disease activity biomarker in ulcerative colitis. Inflamm Bowel Dis 2012;18:2169-79.

Disclosure of Interest : None declared

DOI 10.1136/annrheumdis-2014-eular.2855

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