title: Novel carbonic anhydrase autoantibodies and renal manifestations in patients with primary Sjogren's syndrome.
abstract: OBJECTIVE
  Anti-carbonic anhydrase II (anti-CA II) antibodies have been related to renal manifestations of primary SS (pSS), and animal studies have even suggested a pathogenic role for them. However, not all pSS patients with renal tubular acidosis (RTA) present with anti-CA II antibodies. Recently, several novel CA isoenzymes have been recognized and we aimed to investigate whether antibodies to these are associated with renal manifestations of pSS.
  
  
  METHODS
  We examined anti-CA II antibodies as well as anti-CA I, VI, VII and XIII antibodies by ELISA tests in 74 pSS patients on whom detailed nephrological examinations had been performed and, as controls, in 56 subjects with sicca symptoms, but no pSS.
  
  
  RESULTS
  The levels of anti-CA I, II, VI and VII antibodies were significantly higher in patients with pSS compared with subjects with sicca symptoms but no pSS. None of the anti-CA antibodies was associated with the presence of complete or incomplete RTA or proteinuria or urinary α₁m excretion in patients with pSS. However, levels of anti-CA II, VI and XIII antibodies correlated significantly with urinary pH, and inversely with serum sodium concentrations. The degree of 24-h urinary protein excretion correlated weakly with levels of anti-CA VII antibodies.
  
  
  CONCLUSIONS
  Not only antibodies to CA II, but also anti-CA VI and XIII antibodies seem to be associated with renal acidification capacity in patients with pSS.
authors.affiliation: Department of Internal Medicine, Rheumatology Centre, Tampere University Hospital, Tampere, Finland. marja.pertovaara@uta.fi
authors.forename: Marja
authors.initials: M
authors.lastname: Pertovaara
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Bootorabi
authors.forename: Marianne
authors.initials: M
authors.lastname: Kuuslahti
authors.forename: Amos
authors.initials: A
authors.lastname: Pasternack
authors.forename: Seppo
authors.initials: S
authors.lastname: Parkkila
mesh_terms: D000141:Acidosis, Renal Tubular / Q000201:enzymology / Q000276:immunology / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000941:Antigens / Q000276:immunology; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D002256:Carbonic Anhydrases / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012859:Sjogren's Syndrome / Q000201:enzymology / Q000276:immunology / Q000473:pathology*; D012964:Sodium / Q000097:blood
chemical_list: D000941:Antigens; D001323:Autoantibodies; D007527:Isoenzymes; C035812:renal tubular antigen; D012964:Sodium; D002256:Carbonic Anhydrases