Value of systematic minor salivary gland biopsy in interstitial lung disease

<bold>Background:</bold> Etiological diagnosis process in interstitial lung diseases (ILD) is challenging. Many explorations are needed to reach a diagnosis. <bold>Objectives:</bold> We aim to study the contribution of systematic minor salivary glands biopsy MSGB in ILD. <bold>Methods:</bold> We conducted a retrospective study in a department of internal medicine between 2015 and septembre 2023. We considered patients with ILD of unknown etiology to whom systematic MSGB was performed. Positive MSGB is defined by the presence of focal lymphocytic sialadenitis with a focus score≥1. <bold>Results:</bold> The data of 128 patients were analysed. MSGB was positive in 32 cases (25%). Positive and negative MSGB groups were respectively compared. The sex ratio was 0,5 in both groups. The patients reported subjective dry eyes and/or dry mouth in 69% vs 45% (p=0,022). The unstimulated salivary flow rate was≤0.1 ml/min 25% vs 13,6 % of the cases (p=0,238). Ophtalmological examination confirmed dry eyes in 53% vs 45% (p=0,43). Respiratory signs concerned almost 90% of the patients in the two groups, while extra-thoracic signs were noted in 78% vs 65% of the patients. Our patients were classified as nonspecific interstitial pneumonia pattern (22% vs 25%), usual interstitial pneumonia (31% in both groups), and organizing pneumonia (15% vs 7%). The positivity of anti-Ro52 was significantly different between the two groups (33% vs 9%, p=0,006). Positivity of the MSGB was correlated to nonidiopathic ILD (87,5% vs 46%, p=0). Using the ACR/EULAR 2016 criteria for Sjögren's syndrome, 78% vs 2% of the patients were diagnosed with this disease (p=0). <bold>Conclusion:</bold> MSGB should be included in the first-line assessment of idiopathic ILD, since it is minimally invasive and contributive.