title: Measuring decreased serum IgG sialylation: a novel clinical biomarker of lupus.
abstract: BACKGROUND
  The aim of this work was to develop a simple assay to distinguish between patients with rheumatoid arthritis (RA) and patients with systemic lupus erythematosus (SLE) by measuring the serum sialylated IgG (SAIgG).
  
  
  METHODS
  Using a newly established SNA-based ELISA method, we compared the sialylation of immunoglobulin G (IgG) from a healthy control group (n = 41), RA patients (n = 30), SLE patients (n = 45), patients with neuropsychiatric SLE (NPSLE) (n = 30) and patients with juvenile idiopathic arthritis (JIA) (n = 32).
  
  
  RESULTS
  The average SAIgG level in healthy control individuals, RA patients, JIA patients, SLE patients and NPSLE patients was 0.64 ± 0.17, 0.82 ± 0.33, 0.69 ± 0.23, 0.12 ± 0.02 and 0.03 ± 0.01 mg/ml, respectively. The ratio of sialylated IgG to total IgG was significantly decreased in the SLE group (1.88 ± 0.32%) compared with the healthy population (4.64 ± 0.90%).
  
  
  CONCLUSIONS
  In summary, while the mean serum SAIgG level of RA and JIA patients was similar to that of the healthy population, there was a significant decrease in the serum SAIgG of both SLE groups tested, whereby the level of the NPSLE population group was the lowest.
authors: Department of Rheumatology, Renji Hospital, School of Medicine, Jiaotong University, Shanghai, China xiaoxiang0721@126.com.
authors: X-X
authors: XX
authors: Chen
authors: Department of Rheumatology, Renji Hospital, School of Medicine, Jiaotong University, Shanghai, China.
authors: Y-Q
authors: YQ
authors: Chen
authors: Department of Rheumatology, Renji Hospital, School of Medicine, Jiaotong University, Shanghai, China.
authors: S
authors: S
authors: Ye
mesh_terms: D000328:Adult; D000361:Agammaglobulinemia / Q000097:blood* / Q000276:immunology; D001171:Arthritis, Juvenile / Q000097:blood / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000276:immunology; D020945:Lupus Vasculitis, Central Nervous System / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G; D019158:N-Acetylneuraminic Acid
keywords: ELISA assay; Sialylation of immunoglobulin G; autoimmune diseases