Lymphoepithelial lesions in the salivary glands of primary Sjögren's syndrome patients: the perfect storm?

In patients with primary Sjögren's syndrome (pSS), inflamed salivary gland (SG) tissue may contain lymphoepithelial lesions (LELs). LELs are histopathological phenomena whereby B cells are present in hyperplastic ductal epithelium of the SG. Despite the potential role of LELs in pSS pathogenesis, studies on their formation, detection, and prevalence in benign lesions (not complicated with lymphoma) are scarce. Recent evidence however shows that LELs are present in approximately half of the patients with pSS, both in minor and major SGs. Migration of a small number of B cells into the epithelium appears to be a critical initial step in LEL formation. These intra-epithelial B cells are proliferative, exhibit an innate-like phenotype, and may be linked to MALT lymphoma development. Alongside intra-epithelial B cells, the hyperplastic epithelial partner in LELs also engages in the local immune reaction. Epithelial cells are a source of cytokines and chemokines, with CXCL10 in particular playing a potential role in LEL formation. Importantly, LELs also have a negative impact on the maintenance of SG homeostasis by SG progenitor cell (SGPC) populations, likely due to dysregulation of SGPC lineage commitment or induction of plasticity. In conclusion, LEL formation mirrors a perfect storm of B and epithelial cell interaction culminating in increased risk of B cell derailment and SGPC dysregulation in pSS patients. We therefore argue that attenuation of LEL formation is an important treatment goal to preserve SG function and prevent B cell derailment in pSS.

Can salivary gland ultrasonography replace salivary gland biopsy in the diagnosis of Sjögren's syndrome?

Ultrasound is a promising diagnostic method when it comes to assessing the involvement of major salivary glands in patients with primary Sjögren's syndrome (pSS). A matter of debate is whether ultrasound of the major salivary glands (SGUS) can replace a salivary gland biopsy in the diagnosis or classification of pSS. The intra- and inter-observer reliability of SGUS was found to be good, especially when focusing on hypoechogenic areas and homogeneity, and comparable to the reliability of histopathologic characteristics of salivary gland biopsies of pSS patients. However, replacing salivary gland biopsy by SGUS led to substantial decrease of the accuracy of the 2016 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria with clinical diagnosis as the gold standard. When SGUS was added as an additional item to the criteria, the accuracy of the criteria remained high, offering at the same time the clinicians a wider array of tools to assess patients. Combination of SGUS and anti-SSA antibodies was shown to be highly predictive of the classification of a patient suspected of pSS, making routine salivary gland biopsy debatable.