Serum leucine-rich α2-glycoprotein is a useful biomarker for monitoring disease activity in patients with adult-onset Still's disease

Scand J Rheumatol. 2015;44(5):399-403. doi: 10.3109/03009742.2015.1016103. Epub 2015 Jun 16.

Abstract

Objective: 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.

Method: We enrolled 39 patients with AOSD, 47 patients with rheumatoid arthritis (RA), and 39 controls. Forty-five serum samples from the patients with AOSD were assayed for LRG using an enzyme-linked immunosorbent assay (ELISA). Comprehensive AOSD activity was determined by a 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 (33.9±15.2 ng/mL, p<0.001 and 22.4±6.1 ng/mL, p<0.001, respectively). Patients with active AOSD had significantly higher LRG levels 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 (CRP; γ=0.387, p=0.015), lactate dehydrogenase (LDH; γ=0.370, p=0.026), 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 six patients with active AOSD who had follow-up evaluations (p=0.007). The best cut-off value for LRG to distinguish AOSD from RA was 67.9 ng/mL, with a sensitivity of 92.3% and a specificity of 97.9%.

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

MeSH terms

  • Adult
  • Biomarkers / blood
  • C-Reactive Protein / metabolism
  • Case-Control Studies
  • Disease Progression*
  • Female
  • Ferritins / blood
  • Glycoproteins / blood*
  • Humans
  • L-Lactate Dehydrogenase / blood
  • Male
  • Middle Aged
  • Sensitivity and Specificity
  • Severity of Illness Index*
  • Still's Disease, Adult-Onset / blood
  • Still's Disease, Adult-Onset / diagnosis*

Substances

  • Biomarkers
  • Glycoproteins
  • LRG1 protein, human
  • C-Reactive Protein
  • Ferritins
  • L-Lactate Dehydrogenase