Objectives: To investigate the prevalence of anti-alphafodrin antibody in patients with Sjogren syndrome (SS), lupus erythematosus (LE), or both and the association of this antibody with other clinical manifestations.
Design: A study of screening and diagnostic tests. Mean follow-up was 152 months (range, 4-572 months).
Setting: A university hospital associated with a research laboratory in Tokyo, Japan.
Patients: Nine patients with primary SS, 15 patients with SS secondary to LE, and 44 patients with LE alone.
Main outcome measures: Frequencies of clinical and laboratory findings, including anti-alpha-fodrin antibody.
Results: Anti-alpha-fodrin antibody was more commonly detected in patients with primary (7/9; P<.001) and secondary (9/15; P<.001) SS than in those with LE alone (3/44). When patients with primary and secondary SS were combined and compared with those with LE alone, the sensitivity of anti-alpha-fodrin antibody was 67%, specificity was 93%, and both positive and negative predictive values were 84%. The presence of anti-alpha-fodrin antibody was associated with pernio, hyperglobulinemia, rheumatoid factor positivity, and the presence of anti-SS-B (La) antibody (P<.01) but not with annular erythema, photosensitivity, vasculitis, or renal disorder.
Conclusions: Although anti-alpha-fodrin antibody was detected in patients with SS and in those with LE, it seemed to be more valuable for the diagnosis of SS than was anti-SS-A (Ro) because anti-alpha-fodrin was much less prevalent in patients with LE alone. It may be possible to consider this novel autoantibody as pathophysiologically associated with some extraglandular manifestations characteristically seen in patients with SS.