Significance of anti‐α‐fodrin autoantibody in diagnosis of Sjogren's syndrome

Abstract

AbstractObjective: Anti‐α‐fodrin autoantibody has been reported to be a highly specific and sensitive test for the diagnosis of Sjogren's syndrome (SS). The objective of our report is to investigate the sensitivity and specificity of anti‐α‐fodrin antibody in patients with SS and its correlation with clinical manifestations.Methods: Recombinant human α‐fodrin was used as envelope antigen in enzyme‐linked immunosorbent assay (ELISA) to detect the relatively specific autoantibody in sera of 42 primary SS, 24 secondary SS with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA), and 40 other connective tissue diseases (CTDs) (SLE 17, RA 8, ankylosing spondylitis 5, dermatomyositis 5, systemic schlerosis 3, mixed connective tissue disease 1, Takayasu's disease 1) patients.Results: Antibodies against α‐fodrin were present in 59.5% of primary SS patients, 31.5% of secondary SS patients, 35.0% and 11.3% of other CTD patients and controls, respectively; the specificity of anti‐α‐fodrin antibody was 79.4% in patients with SS. It showed no significant difference between primary and secondary SS (P > 0.05), as well as SS compared with other CTD patients (P > 0.05). The positive rates of antibodies against α‐fodrin in CTD patients were significantly higher than those in non‐CTD patients and normal controls (P < 0.01). The presence of anti‐α‐fodrin antibodies has no significant correlation with clinical manifestations or other autoantibodies, while the levels of sera IgG and erythrocyte sedimentation rate (ESR) are higher in α‐fodrin antibody‐positive patients (IgG: 23.2 vs. 18.6, P < 0.05; ESR: 52.9 vs. 37.1, P < 0.05) than α‐fodrin antibody‐negative patients. Anti‐α‐fodrin antibodies are all negative in anti‐SS antigen A and antinuclear antibody‐negative SS patients.Conclusion: The result showed a lower sensitivity and specificity for anti‐α‐fodrin antibody as a diagnostic marker of SS, compared with previous reports. Anti‐α‐fodrin antibodies had no significant association with clinical manifestations, but might be related to the sera IgG level. Antibodies against α‐fodrin played no important roles in diagnosis of antibody‐negative SS patients.