Objective: The aim of the present study was to evaluate the diagnostic value of quantitative immunohistologic criteria for Sjögren's syndrome (SS) in labial salivary gland biopsies.
Methods: Quantitative immunohistologic examination was performed on labial salivary gland biopsy samples from 80 healthy controls, 32 patients with primary SS, 14 patients with secondary SS, 5 with "probable" SS, 36 with keratoconjunctivitis sicca (KCS) with a lymphocytic focus score less than 1 on the lip biopsy, and 18 with rheumatoid arthritis (RA) without clinical evidence of SS.
Results: This is the first study to show that immunohistologic criteria for SS, based on the percentages of IgA-containing and IgG-containing plasma cells, are able to 1) confirm the diagnosis of SS in labial salivary glands of KCS patients in the absence of grade IV lymphocytic adenitis; and 2) distinguish between a grade IV focal lymphocytic adenitis in the labial salivary glands of SS patients and of RA patients without SS.
Conclusion: Quantitative immunohistologic criteria were shown to be much more sensitive and disease specific than the widely accepted grade IV lymphocytic adenitis criterion, which corresponds to a lymphocytic focus score greater than 1, and these criteria should be included in the international diagnostic criteria for Sjögren's syndrome.