Digital image analysis of intraepithelial B-lymphocytes to assess lymphoepithelial lesions in salivary glands of Sjögren’s syndrome patients

Abstract

Objective Salivary glands of primary Sjögren’s syndrome (pSS) patients characteristically harbour periductal infiltrates in which lymphoepithelial lesions (LELs) can develop. LELs are composed of hyperplastic ductal epithelium with infiltrating lymphocytes and may assist in the challenging diagnostic process of pSS. As manual identification of LELs remains difficult, we aimed to identify LELs by using an objective digital image analysis (DIA) algorithm that detects intraepithelial lymphocytes. Methods A virtual triple staining technique developed for this study was used to count intraepithelial lymphocytes in consecutive slides stained for CD3 (T-lymphocytes), high molecular weight cytokeratin (hmwCK) (striated ducts) and CD20 (B-lymphocytes) in labial and parotid gland biopsies in a diagnostic cohort of 109 sicca patients. Patients were classified as pSS or non-SS according to the ACR-EULAR classification criteria. Results T-lymphocytes were detected in almost all analyzed ducts of pSS and non-SS patients, whereas intraepithelial B-lymphocytes were present in 59–68% of labial and parotid gland biopsies of pSS patients, against only 2–3% of patients classified as non-SS. Intraepithelial B-lymphocytes were found in almost all striated ducts with hyperplasia (LELs). Remarkably, around 25% of analyzed striated ducts without hyperplasia of pSS patients also contained B-lymphocytes (precursor-LELs). Furthermore, presence of intraepithelial B-lymphocytes was associated with clinical parameters of pSS (i.e. serology). Conclusion Intraepithelial B-lymphocytes are a specific finding in salivary gland biopsies of pSS patients and can be used as an objective alternative to LEL scoring. Therefore, identification of B-lymphocyte containing ducts should be added to the diagnostic histopathological work-up of patients suspected of pSS.

Parotid salivary sodium levels of Sjögren's syndrome patients suggest B-cell mediated epithelial sodium channel disruption

“…Expression of ENaC appeared to be aberrant in FS+ SS patients both with and without lymphoepithelial lesions (LELs), implying that a soluble factor secreted by B cells is a likely candidate for dysregulation of ENaC expression, and not per se the physical invasion of the striated ducts by B cells, or the epithelial hyperplasia. The maximum LEL severity score was also correlated with sodium concentration, a likely surrogate readout for the number of B cells close to the ducts, considering that more severe LELs are associated with more intraepithelial B cells (9). The potential involvement of B cells in sodium dysbalance is also supported by the observation that striated ducts distal to inflammatory foci do not display dysregulated ENaCs.…”

“…A lymphoepithelial lesion (LEL) is considered to be represented by hyperplastic epithelial cells of the striated ducts, in which lymphocytes are present (23). We have previously published a scoring system to allow grading of LELs, according to the following criteria and the publication of van Ginkel (9,22,24). Briefly, Stage 0 SDs contained lymphocytes but no epithelial hyperplasia.…”

“…Infiltrates are associated with the striated ducts and form periductal foci (defined as clusters of more than ≥50 lymphocytes), sometimes displaying further architectural patterning comprising follicular dendritic cell networks and germinal centers. Lymphocytes also invade the striated ducts, in a symbiotic relationship that appears to stimulate proliferation of both epithelial cells and B cells (lymphoepithelial lesions, LELs (9)). Five to ten percent of SS patients develop mucosa-associated lymphoid tissue (MALT) lymphomas, the origin of which is proposed to be B cells resident in LELs in the parotid SG (5,10).…”

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

“…LELs can be identified by an experienced pathologist based on haematoxylin and eosin staining. For the less experienced eye and in difficult cases, additional immunohistochemical staining for high molecular weight cytokeratins (hmwCKs) aids in standardised assessment of LELs to define ductal borders and prevent misinterpretation of LELs as ectopic germinal centres (2,5,6).…”

Why Should We Consider Potential Roles of Oral Bacteria in the Pathogenesis of Sjögren Syndrome?

“…Chemokines expressed by ductal cells might be responsible for the periductal recruitment of T cells, B cells, and dendritic cells (DCs). In particular, infiltration of the ductal epithelium with disrupted basal lamina by CD4 + T cells, CD8 + T cells, and B cells and formation of lymphoepithelial lesions are unique to the salivary glands in SS ( 19 20 ). As potent producers of IFNα, plasmacytoid DCs (pDCs) detected in the SS-affected salivary glands are believed to play a central role in maintaining the well-known IFN signature of SS ( 21 ).…”