Clinical characteristics and biopsy accuracy in suspected cases of Sjögren's syndrome referred to labial salivary gland biopsy

Abstract

Background: Labial salivary gland biopsy (LSGB) is the most important diagnostic tool for the diagnosis of Sjögren's syndrome (SS), but its diagnostic value is rarely studied. This study assessed the sensibility and specificity of LSGB, and the clinical profiles of patients who were referred for biopsy.

Methods: Retrospective analysis of the histopathological reports from LSGB and medical report data from patients who underwent LSGB between 2008 and 2011 was conducted.

Results: About 290 biopsies were performed and 74 were excluded due to insufficient clinical data. Of the 216 patients, 0.46% was carrier of hepatitis C virus, 30.1% had primary SS (pSS), and 8.8% had secondary SS (sSS). Of the samples, 94.3% presented dryness symptoms, 51.6% experienced dryness only, 42.7% had systemic manifestations, and 66.9% presented low unstimulated salivary flow and/or Schirmer's test. LSGB was necessary in 67.6% to confirm the presence of SS based on the American-European Consensus Group 2002 criteria (AECG). Based on specialist's opinion, sensibility level was 86.57%, and specificity was 97.43%. Positive predictive value (PPV) was 95%, and negative predictive value (NPV) was 92.6%. Determined accuracy was 93.3%. Concordance (kappa coefficient) of LSGB and specialist's opinion was 0.851, and LSGB with AECG criteria was 0.806. Of the 98 patients referred with fibromyalgia and dryness, 36.7% had SS and LSBG focus score of ≥ 1. Patients with SS were older, and showed more severe lachrymal and salivary dysfunctions, greater frequency of fibromyalgia, anti-nuclear antibodies (ANA), anti-SSA-Ro, and anti-SSB-La.

Conclusions: Labial salivary gland biopsy has high sensibility, specificity, positive and negative predictive values for diagnosis of pSS. In the clinical practice, it is useful, especially for those patients with glandular dysfunctions and negative antibodies.

Figure 1

Flow chart study. pSS: primary Sjögren’s syndrome according to AECG, sSS: secondary Sjögren’s syndrome according to AECG, 8 SLE: Systemic Lupus Erythematosus, 6 RA: Rheumatoid Arthritis, 3 Overlap (SSc: Systemic Sclerosis, APS: Antiphospholid Syndrome, SS: Sjögren’s syndrome).

Figure 2

Diagnostic flow of suspected patients of Sjögren’s syndrome. USF: unstimulated salivary flow; ST: Schirmer test; anti-SSA/SSB +: anti-SSA and/or anti-SSB positive; anti-SSA/SSB -: anti-SSA and/or anti-SSB. negative; Biopsy +: score focus ≥ 1; Biopsy -: focus score < 1; no SS: no Sjögren’s. syndrome; pSS: primary Sjögren’s syndrome according to the American European. Consensus Group 2002.