FRI0594 Is Lymphocytic Sialadenitis IGG4-Related? An Observational Study

BackgroundIgG4-related disease is a systemic fibroinflammatory condition characterized by a dense IgG4-positive lymphoplasmocytic infiltrate in involved organs. Salivary gland is one of the most common sites of the disease and, besides submandibular and parotid glands, minor lip salivary glands involvement has been describedObjectivesThe main objective of our study was to determine the prevalence of IgG4-related disease among patients with well-defined lymphocytic sialadenitis on labial salivary gland biopsyMethodsAll labial salivary gland biopsies (LSGB) performed in a French University Hospital Center over a one-year period were retrospectively screened. IgG4 immunostaining was performed on all LSGB showing lymphocytic sialadenitis defined by a Chisholm score ≥3. Histopathological criteria for IgG4-related disease according to international criteria and final diagnosis associated with lymphocytic sialadenitis were analyzed in all cases.ResultsThree hundred and fifty patients had a labial salivary gland biopsy (LSGB). Among them, 79 (23%) had a lymphocytic sialadenitis. Mean age was of 55.5±15.7 years old. Female/Male Sex ratio was 3.2/1. LSGB was performed because of sicca symptoms in most cases (48/79, 60.8%). Only one (1/79, 1.3%) LSGB showed histopathological features of IgG4-related disease in a patient who otherwise displayed obvious extra-salivary features of IgG4-related disease. Overall, the diagnoses associated with lymphocytic sialadenitis were Sjögren's syndrome (29/79, 36.7%), other autoimmune disorders (besides Sjogren's syndrome) (17/79, 21.5%), idiopathic pulmonary fibrosis (5/79, 6.3%), sarcoidosis (3/79, 3.8%), B-cell hemopathy (3/79, 3.8%), hepatitis C infection (2/79, 2.5%), unclassified arthritis (1/79, 1.3%), idiopathic uveitis (1/79, 1.3%), multiple sclerosis (1/79, 1.3%) and tuberculosis (1/79, 1.3%). In 15 cases (19%), no diagnosis could be obtained despite extensive work-up. Of note, IgG4 staining was negative in all patients with unexplained lymphocytic sialadenitis.ConclusionsThe prevalence of IgG4-related disease among patients with lymphocytic sialadenitis on LSGB is very low. Hence, IgG4 immunostaining has a poor diagnostic yield and should not be systematically performed in lymphocytic sialadenitis. On the other hand, LSGB, by being simple and safe, can be useful for a definite diagnosis when IgG4-related disease is suspectedDisclosure of InterestNone declared