Objective: To compare the specificity and sensitivity of antibodies against SSA and SSB, anti-M3 receptor polypeptide antibodies, anti-alpha-fodrin (IgG) antibodies in primary Sjögren's syndrome (pSS).
Methods: One hundred and ten pSS patients (mean age was 49.2 +/- 14. 8, mean disease duration was 5.6 +/- 4.6), 80 systemic lupus erythematosus (SLE) patients (mean age was 25.5 +/- 4.6, mean disease duration was 2.5 +/- 1.2) and 80 rheumatoid arthritis (RA) patients (mean age was 44.6 +/- 3.5, mean disease duration was 4.2 +/- 1.1) were studied. Enzyme-linked immunosorbent assay was used to measure these antibodies.
Results: The seropositive rates of anti-SSA, anti-SSB antibodies, anti-M3 receptor polypeptide antibodies and anti-alpha-fodrin (IgG) antibodies were 45.5%, 30.9%,78.2% and 77.3%, respectively in pSS. They were much higher than those in RA and SLE patients (P < 0.05). Specificities of SSA, SSB antibodies, anti-M3 receptor antibodies and anti-alpha-fodrin IgG were 83.8%, 97.7%, 92.0% and 90.0% respectively. With the combination of these antibodies in the diagnosis of pSS, the sensitivity can be increased at least to 88.2% and the specificity was not decreased significantly.
Conclusion: Combination of these antibodies can significantly improve the sensitivity of these antibodies in the diagnosis of pSS. Anti-SSA and SSB antibodies, anti-M3 receptor antibodies and anti-alpha-fodrin (IgG) antibodies are specific antibodies for the diagnosis of pSS.