Diagnostic Value and Predictive Factors for a Positive Labial Minor Salivary Gland Biopsy for Sjögren’s Syndrome in a Tunisian Population

To examine the performance of the minor salivary gland biopsy (MSGB) to diagnose Sjögren's syndrome (SS) and to identify predictive factors for MSGB's positivity in Tunisian SS-suspected patients. In a retrospective study, histopathological evaluation of MSGB from SS suspected- patients were examined. The classifications of the American-European Consensus Group (AECG, 2002) and the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR, 2016) have been applied. We classified a positive MSGB when a focus score ≥ 1 and/or Chisholm and Mason grading ≥ 3 were observed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MSGB were assessed, and the area under the ROC curve was performed to evaluate its diagnostic accuracy. One hundred and two MSGBs were examined. They were positive in 48 patients (47%). For the positive diagnosis of SS, MSGB had 77,6% sensitivity, 93,2% specificity, 93,8% PPV and 75,9% NPV. With an air under the curve (AUC) of 0.854, MSGB was considered an excellent discriminating test in SS diagnosis. Keratoconjunctivitis sicca (p=0.04), elevated erythrocyte sedimentation rate (p=0.036), leukopenia (p=0.025), positive antibodies: anti-Ro/SSA (p=0.029), anti-Ro/SSA, anti-La/SSB (p=0.037), antinuclear (p=0.01), anti-extractable nuclear antigen (p=0.04), positive rheumatoid factor (p=0.032), positive elevated IgG levels (p=0.03) and abnormal unstimulated whole salivary flow rate (p=0.002) were predictive of a positive MSGB. In cases of suspected SS, a predictive scoring system incorporating these clinical and biological factors will streamline MSGB indications and serve as a diagnostic tool for positive SS diagnosis in research studies.