title: Increased levels of autoantibodies against catalase and superoxide dismutase associated with oxidative stress in patients with rheumatoid arthritis and systemic lupus erythematosus.
abstract: OBJECTIVE
  To evaluate the level of autoantibodies against superoxide dismutase (SOD) and catalase (CAT) in the sera of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) Tunisian patients, to study the oxidative profile among the same patients and to establish a correlation between the two parameters in order to understand the role of each one in the genesis of the two diseases.
  
  
  METHODS
  Using a standard enzyme-linked immunosorbent assay (ELISA), the levels of immunoglobulin G (IgG) and IgM directed against CAT and SOD in the sera of 39 RA patients, 40 SLE patients, and 50 control healthy individuals were evaluated. The oxidative/antioxidative profile was tested by measuring serum malondialdehyde (MDA), conjugated dienes (CD), CAT activity, and SOD activity.
  
  
  RESULTS
  Our data showed increased levels of IgG antibodies (Ab) against CAT in both groups of patients (p<0.05) compared to control subjects. However, the SLE patients displayed an increased level of anti-SOD IgG (p<0.05). In all patients the lipid peroxidation was confirmed by high levels of MDA and conjugated dienes (p<0.05). RA patients exhibited an increasing CAT and SOD activity in their sera (p<0.05) with a positive correlation observed between CAT and IgG anti-CAT (p<0.05). The same results were observed for SLE patients. In addition, a positive correlation was observed between anti-CAT Ab and anti-SOD Ab in SLE patients (p<0.05).
  
  
  CONCLUSIONS
  Collectively, these results suggested that the primary factor causing the oxidative stress observed in RA and SLE is excessive free radical production rather than impaired CAT or SOD activity due to autoantibody inhibition.
authors.affiliation: Units of Biotechnology and Pathology, Higher Institute of Biotechnology of Sfax, Sfax, Tunisia. riadhbm2004@yahoo.fr
authors.forename: R Ben
authors.initials: RB
authors.lastname: Mansour
authors.forename: S
authors.initials: S
authors.lastname: Lassoued
authors.forename: B
authors.initials: B
authors.lastname: Gargouri
authors.forename: A
authors.initials: A
authors.lastname: El Gaïd
authors.forename: H
authors.initials: H
authors.lastname: Attia
authors.forename: F
authors.initials: F
authors.lastname: Fakhfakh
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D002374:Catalase / Q000097:blood / Q000276:immunology*; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D015227:Lipid Peroxidation / Q000502:physiology; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology*; D008315:Malondialdehyde / Q000097:blood; D018384:Oxidative Stress / Q000276:immunology*; D013482:Superoxide Dismutase / Q000097:blood / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D005609:Free Radicals; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008315:Malondialdehyde; D002374:Catalase; D013482:Superoxide Dismutase