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.
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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
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