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Sensitivity and specificity for primary Sjögren's syndrome of IgA and IgG anti-alpha-fodrin antibodies detected by ELISA.

OBJECTIVE
To investigate the sensitivity and specificity of anti-alpha-fodrin antibodies in patients with primary Sjögren's syndrome (pSS).


METHODS
IgA and IgG anti-alpha-fodrin antibodies were measured in the sera of 80 patients with pSS, 60 blood donors matched for age and sex, 50 patients with systemic lupus erythematosus (SLE), 30 with rheumatoid arthritis (RA), 20 with systemic sclerosis (SSc), and 10 with polymyositis or dermatomyositis (PM/DM) by an ELISA method employing recombinant human alpha-fodrin as antigen.


RESULTS
The sensitivity of IgA and IgG anti-alpha-fodrin antibodies for pSS was 32.50% and 21.25%, respectively. When the prevalence of these antibodies in patients with SLE, RA, SSc, and PM/DM was evaluated, we observed specificity of these antibodies of 68.18% and 79.09%, respectively. The sensitivity and specificity for pSS of the combined determination of IgA and IgG anti-alpha-fodrin antibodies were 40% and 58.18%, respectively.


CONCLUSION
The prevalences of IgA and IgG anti-alpha-fodrin antibodies in our patients with pSS and other chronic autoimmune diseases have induced us to doubt their use as diagnostic markers of pSS.