Diagnostic accuracy of anti-alpha-fodrin antibodies for primary Sjögren's syndrome

Minor salivary gland biopsy: Its role in the classification and prognosis of Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disorder characterized by mononuclear cell infiltration in the exocrine glands, which leads to sicca syndrome (xerostomia and xerophthalmia). The etiology of SS is unknown, but multiple environmental factors (infectious, hormonal and stress-related), as well as genetic factors, may play a role in its pathogenesis. The diagnosis of SS is complex considering its clinical and paraclinical parameters may not be very specific. The minor salivary gland biopsy (MSGB) has undoubtedly become crucial for classifying and determining the prognosis of SS. The three main different classification systems for its interpretation have been described by Chisholm and Mason, Greenspan and Daniels, and Tarpley. However, this invasive procedure has variable sensitivity and specificity as well as low reproducibility. The use of additional methods, such as skin biopsy, imaging techniques, and serum/salivary biomarkers, may be combined with current methods to develop a bioscore that could increase diagnostic performance. In this review, we summarized the main pathological findings in SS and the prognosis of patients with SS according to the biopsy results.

Autoantibodies Associated With Connective Tissue Diseases: What Meaning for Clinicians?

Connective tissue diseases (CTDs) such as systemic lupus erythematosus, systemic sclerosis, myositis, Sjögren's syndrome, and rheumatoid arthritis are systemic diseases which are often associated with a challenge in diagnosis. Autoantibodies (AAbs) can be detected in these diseases and help clinicians in their diagnosis. Actually, pathophysiology of these diseases is associated with the presence of antinuclear antibodies. In the last decades, many new antibodies were discovered, but their implication in pathogenesis of CTDs remains unclear. Furthermore, the classification of these AAbs is nowadays misused, as their targets can be localized outside of the nuclear compartment. Interestingly, in most cases, each antibody is associated with a specific phenotype in CTDs and therefore help in better defining either the disease subtypes or diseases activity and outcome. Because of recent progresses in their detection and in the comprehension of their pathogenesis implication in CTD-associated antibodies, clinicians should pay attention to the presence of these different AAbs to improve patient's management. In this review, we propose to focus on the different phenotypes and features associated with each autoantibody used in clinical practice in those CTDs.

Usefulness of IgA Anti-α-fodrin Antibodies in Combination with Rheumatoid Factor and/or Antinuclear Antibodies as Substitute Immunological Criterion in Sjögren Syndrome with Negative Anti-SSA/SSB Antibodies

OBJECTIVE

We aimed to evaluate the usefulness of anti-α-fodrin antibodies (AFA) in combination with rheumatoid factor (RF) and/or antinuclear antibodies (ANA) as an alternative immunological criterion for Sjögren syndrome (SS) among patients with negative anti-Ro/La serology.

METHODS

The study included 350 patients (100 with rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, and 50 with primary SS) randomly selected and assessed for SS. All patients were tested for ANA, RF, anti-SSA/SSB, and AFA antibodies. SS diagnosis was made on a clinical basis by 2 rheumatologists based on the 6-item screening questionnaire, Schirmer-I test, nonstimulated whole salivary flow rate, fluorescein staining test, autoantibodies, lip biopsy, and medical chart review. Non-SS was defined as lack of clinical diagnosis and not fulfilling the American-European Consensus Group classification criteria and the American College of Rheumatology (ACR) criteria. The ACR criteria were applied substituting the immunological criteria as follows: (1) RF plus ANA > 1:320, (2) RF plus AFA, (3) ANA > 1:320 plus AFA, (4) RF alone, and (5) 2 positive tests out of RF, ANA > 1:320, or AFA. We estimated the sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio positivity with 95% CI for each criterion.

RESULTS

There were 236 patients (67%) who tested negative for anti-SSA/SSB antibodies, of whom 65 (27.5%) were clinically diagnosed as SS, and 149 (63%) with non-SS. RF + AFA and ANA + AFA performed similarly to RF + ANA > 1:320. The model 2 out of 3 of RF, ANA, or AFA improved the sensitivity from 56.9% to 70.7%, although the specificity decreased.

CONCLUSION

The combination AFA + RF, AFA + ANA > 1:320, or at least 2 out of 3, performed well as a proxy immunological test for patients with SS and negative Ro/La serology.

Autoantibodies in Sjögren's Syndrome

We compiled information on antibodies in Sjögren syndrome, focusing more on clinical manifestations associated with anti-Ro/SSA and anti-La/SSB antibodies and studies regarding novel antibodies. We reviewed previous as well as most recent studies with the subject heading Sjogren in combination with antibodies and congenital heart block (CHB). Almost half of asymptomatic mothers giving birth to children with CHB ultimately develop Sjögren. We discussed studies concerning the presence of antibodies predating clinical manifestations of disease. Studies in the future are required to ascertain the pathogenic mechanisms associated with these antibodies and the specific clinical manifestation related to new autoantibodies.

Role of salivary anti-SSA/B antibodies for diagnosing primary Sjögren's syndrome

The diagnosis of primary Sjögren's syndrome (pSS) is complex, and the saliva test is a potential method to improve the existing diagnostic criteria.

OBJECTIVE

To estimate the diagnostic accuracy of salivary anti-SSA/B antibodies in primary Sjögren's syndrome (pSS), and to analyze their correlations with clinical and laboratory profiles.

STUDY DESIGN

This study enrolled 100 pSS patients and 140 non-pSS controls, including 40 rheumatoid arthritis (RA) patients, 40 systemic lupus erythematosus (SLE) patients, and 60 healthy controls. Unstimulated whole saliva and stimulated parotid saliva samples were collected from the subjects. Salivary anti-SSA/B antibodies were measured using an enzyme-linked immunosorbent assay (ELISA). Clinical and laboratory data were retrieved from the medical records.

RESULTS

In the pSS group, the sensitivity of anti-SSA and anti-SSB antibodies in whole saliva was 49% and 29%, respectively, and the specificity was 87.5% and 95%. The sensitivity of anti-SSA and anti-SSB antibodies in parotid saliva was 32% and 8%, respectively, and the specificity was 95.52% and 97.86%, respectively. In the pSS group, the diagnostic accuracy of anti-SSA/B antibodies in whole saliva was significantly higher than in parotid saliva (p<0.05), but was significantly lower than in serum (p<0.05). The salivary flow rate in the pSS group positive for whole salivary anti-SSA was significantly lower than in the negative group (p<0.05). The prevalence of rheumatoid factor and antinuclear factor were significantly higher in salivary SSB-positive pSS patients than in SSB-negative patients (p<0.05).

CONCLUSIONS

Compared to parotid saliva, whole saliva is a more suitable diagnostic fluid. Using salivary anti-SSA/B antibodies as a single test item is insufficient given the relatively low sensitivity. Further studies should investigate the possibility of combining tests for different salivary autoantibodies as a method for diagnosing pSS.