title: Prospective study of the clinical value of determining circulating IgA-alpha 1-antitrypsin complex using a prototype ELISA kit in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To evaluate the clinical value of determining circulating IgA-alpha 1-antitrypsin (IgA-AT) complex in rheumatoid arthritis.
  
  
  METHODS
  The IgA-AT complex was assayed by a prototype ELISA kit using a specific monoclonal antibody against the complex.
  
  
  RESULTS
  The median level of serum IgA-AT complex in rheumatoid patients (2.26 AU ml-1) was significantly higher than in osteoarthritis patients (1.37 AU ml-1, P < 0.05) and healthy volunteers (1.03 AU ml-1, P < 0.001). The concentration of IgA-AT complex in rheumatoid arthritis patients at baseline was correlated with the number of painful joints (P < 0.05), number of swollen joints (P < 0.01), erythrocyte sedimentation rate (P < 0.05), and modified Lansbury index (P < 0.01). The median serum level of IgA-AT complex in rheumatoid patients at baseline was higher than that at three months (P < 0.01), six months (P < 0.01), and 12 months (P < 0.01) after the start of treatment. The difference and ratio of IgA-AT complex levels before and after treatment were significantly associated with radiographic progression.
  
  
  CONCLUSIONS
  The findings validate the usefulness of determining IgA-AT complex using ELISA in the management of rheumatoid arthritis.
authors.affiliation: Division of Rheumatology and Molecular Immunology, St. Marianna University School of Medicine, Kawasaki, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Iwana
authors.forename: S
authors.initials: S
authors.lastname: Aotsuka
authors.forename: K
authors.initials: K
authors.lastname: Nishioka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000936:Antigen-Antibody Complex / Q000097:blood*; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D001799:Blood Sedimentation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000276:immunology*; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D012720:Severity of Illness Index; D000515:alpha 1-Antitrypsin / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D018501:Antirheumatic Agents; D007070:Immunoglobulin A; D011933:Reagent Kits, Diagnostic; D000515:alpha 1-Antitrypsin