The prognostic value of routinely performed minor salivary gland assessments in primary Sjögren's syndrome.

OBJECTIVES: To investigate the prognostic value of the lymphocytic focus score (LFS) and the percentages of IgA+, IgM+ and IgG+ plasma cells for disease severity of primary Sjögren syndrome (pSS).

METHODS: Medical charts of 174 pSS patients were retrospectively analysed, comparing histology results (LFS and percentages of IgA+, IgM+ and IgG+ plasma cells) with disease outcomes as non-Hodgkin lymphoma (NHL) and clinical scores including cumulative EULAR (European League against Rheumatism) Sjögren syndrome disease activity index (ESSDAI) and the total number of extraglandular manifestations.

RESULTS: The mean LFS was significantly higher in patients developing NHL (3.0±0.894 vs 2.25±1.086; p=0.021). The threshold of ≥3 foci has a positive predictive value of 16% for lymphoma, and a negative predictive value of 98%. Only LFS ≥3 contributed significantly and independently to NHL development in a standard multiple regression model. Ig class distribution of plasma cells did not help to identify patients developing lymphoma. Patients with LFS ≥3, ≤40% IgA+ or ≥25% IgM+ plasma cells in salivary gland biopsy specimens had significantly enhanced systemic disease.

CONCLUSIONS: Routine histopathological minor salivary gland assessment has important prognostic value. The LFS might help to identify patients with an increased risk for lymphoma.