Predictive and prognostic value of antinuclear antibodies and rheumatoid factor in primary Sjogren's syndrome

Aims: To assess the predictive and prognostic value of antinuclear antibodies (ANA) and rheumatoid factor (RF) in primary Sjögren's syndrome (pSS). Methods: This retrospective study includes 201 patients that fulfilled the 1993 European preliminary classification criteria for pSS. The patients were further categorized by the 2002 revised criteria, with or without the inclusion of ANA and RF as classification criteria, and were further subgrouped by the presence of ANA, RF, anti-SS-A, and anti-SS-B, and different ANA titers. The clinical manifestations, serological markers, and results of lip biopsies among these subgroups were compared. Results: Our results showed pSS patients who are seropositive for one of the following markers: ANA, RF, anti-SS-A, or anti-SS-B are younger, predominantly female, and had more serological abnormalities than those with seronegativity of ANA, RF, anti-SS-A, or anti-SS-B. Higher ANA titers (≥ 1: 640) correlated with higher frequency of serum anti-SS-A+ and anti-SS-B+, and elevations of serum immunoglobulin G and A in all three different classification criteria groups. The clinical manifestations and laboratory results in the 2002 revised criteria groups with or without the inclusion of ANA and RF as classification criteria items were highly concordant. Conclusion: Regardless of the classification criteria for pSS, patients who are seropositive for one of the ANA, RF, anti-SS-A and anti-SS-B biomarkers are more likely to have autoimmune-related Sjögren's syndrome. ANA and RF have shown to possess the predictive and prognostic values for those who do not fulfill the higher stringent 2002 revised criteria but are indicated for immunomodulatory therapy. Thus we suggest that ANA and RF should be reconsidered as items of classification criteria for pSS.