To compare sensitivity and specificity of autoantibodies to alpha-fodrin with conventional anti-Ro and anti-La antibodies in patients with primary Sjögren's syndrome (pSS). Data on internal organ manifestations were correlated with presence of autoantibodies.
We collected clinical and laboratory data from 321 patients with pSS (Copenhagen criteria), of which 205 fulfilled the new American-European 2002 consensus criteria. Sera were tested for autoantibodies against alpha-fodrin and recombinant Ro-52, Ro-60, and La proteins.
Antibodies to alpha-fodrin were not diagnostically superior to conventional anti-Ro/La testing. IgG anti-La had the highest specificity (97%). A highly significant association was found between presence of anti-La and internal organ manifestations (OR 6, 95% CI 2.99-12.03) or hematological abnormalities. The pattern of autoantibodies was relatively independent of disease duration, indicating that these antibodies appeared early in pSS, probably even years before the first symptoms were manifest.
We could not confirm that antibodies to alpha-fodrin had higher specificity or sensitivity than anti-Ro/La. Anti-La antibodies were strongly correlated to organ involvement and cytopenias, and thus could serve as a prognostic marker in pSS.