Minor salivary gland biopsy in patients with IPAF and suspected Sjogren’s syndrome

Introduction: Interstitial pneumonia with autoimmune features (IPAF) was recently defined to gather interstitial lung diseases (ILD) having suggestive features of a systemic autoimmune process without meeting conventional criteria for a defined connective tissue disease (CTD). Sjogren’s syndrome (SS) frequently involves the respiratory system but as symptoms are unspecific could be under recognized. Objective: Describe the results of Minor salivary gland biopsy (MSGB) in patients with IPAF criteria and possible SS. Methods: Retrospective study including all ILD patients with IPAF and possible SS, evaluated since 2013, which underwent MSGB. Clinical, laboratory and histological data were collected. MSGB was considered positive when 1 or more focus score >50 lymphocytes/4mm3 were founded, except in patients under immunosuppressive treatment, in which the threshold was established in 20-50 lymphocytes/4mm3. Results: Twenty-three patients were included. Median age (±SD) was 74± 8years and 52% were females. Overall, nine MSBG (39%) were considered positive and the diagnosis of SS was confirmed. In those patients, sicca syndrome was present in 6(66%), positive Schirmer in 5(43%) and ANA>1:320 in 3(33%). The median FVC (% predicted) was 78±15%. Non specific interstitial pattern 4(44%) and usual interstitial pattern 4(44%) were the most common radiological findings. In 6 of those patients (67%) the results of MSBG conditioned therapeutic changes. No complications of the MSBG were reported. Conclusions: MSGB could be considered a useful diagnostic tool in patients with IPAF and possible SS. This data should be confirmed in a larger prospective IPAF cohort.