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

Intraepithelial lymphocytes in human oral diseases

Objective

As a distinctive subset of T cells, intraepithelial lymphocytes (IELs) are found in the epithelium of mucosal barrier and serve as the primary defenders of the intestinal mucosal immune system. IELs exhibit phenotypic and functional diversity with high expression of activated marker molecules, tissue-homing integrins, NK cell receptors, cytotoxic T cell-related molecules, and cytokines. Meanwhile, IELs demonstrate differentiation plasticity, antigen recognition diversity, self-reactivity, and rapid "memory" effect, which enable them to play a crucial role in regulating responses, maintaining mucosal barriers, promoting immune tolerance, and providing resistance to infections. In addition, IELs have been explored in autoimmune diseases, inflammatory diseases, and cancers. However, the specific involvement and underlying mechanisms of IELs in oral diseases have not been systematically discussed.

Methods

A systematic literature review was conducted using the PubMed/MEDLINE databases to identify and analyze relevant literatures on the roles of IELs in oral diseases.

Results

The literature review revealed the characteristics of IELs and emphasized the potential roles of IELs in the pathogenesis of oral lichen planus, oral cancers, periodontal diseases, graft-versus-host disease, and primary Sjogren's syndrome.

Conclusion

This review mainly focuses on the involvement of IELs in oral diseases, with a particular emphasis on the main functions and underlying mechanisms by which IELs influence the pathogenesis and progression of these conditions.

Clinical, histopathological, and immunohistochemical characteristics of patients with sicca syndrome with a focus score ≥ 1 in the minor salivary gland biopsy

Introduction

Sjögren’s syndrome is a systemic autoimmune disease. The usefulness of immunohistochemistry in minor salivary gland biopsies has been described to be helpful in indirectly characterizing the lymphocyte phenotype in difficult diagnosis cases.

Objective

To describe sociodemographic, clinical, serological, histopathological, and immunohistochemical variables in patients with sicca syndrome and a minor salivary gland biopsy focus score greater than or equal to one.

Materials and methods

We conducted an observational, retrospective study that included patients under study for potential sicca syndrome whose minor salivary gland biopsy was available and had obtained a focus score greater than or equal to one. Immunohistochemistry was performed on the minor salivary gland biopsy with chromogen red staining for CD8 T lymphocytes and brown staining for CD4 T lymphocytes. Expression ratio of CD20:CD3 and CD4:CD8 markers was determined with the MoticEasyScan Pro 6™ (MOTIC) device and the QuPath™ software. Qualitative variables were analyzed using the chi-square or Fisher’s exact test, and quantitative variables were analyzed according to their assumption of normality.

Results

Twenty-eight patients were analyzed: 16 patients had Sjögren’s syndrome, and 8 of them had polyautoimmunity. An association was found between atrophy in the minor salivary gland biopsy and development of polyautoimmunity (OR = 11.1; 95% CI: 1.12-112; p value = 0.033). The CD20:CD3 and CD4:CD8 ratios were normal, with no statistically significant differences between patients with and without Sjögren’s syndrome. In the subgroup of patients with Sjögren’s syndrome, CD4 T lymphocytes were predominant, with 15 cases out of 16 with CD4:CD8 ratios equal to or greater than 2:1.

Conclusions

Glandular atrophy was associated with the development of polyautoimmunity and a predominance of CD4 T lymphocytes in patients with Sjögren’s syndrome. This finding highlights the potential value of immunohistochemistry of minor salivary gland biopsies in this group.

Immune and non-immune mediators in the fibrosis pathogenesis of salivary gland in Sjögren's syndrome

Sjögren's syndrome (SS) or Sjögren's disease (SjD) is a systemic autoimmune disease clinically manifested as sicca symptoms. This disease primarily impacts the functionality of exocrine glands, specifically the lacrimal and salivary glands (SG). SG fibrosis, an irreversible morphological change, is a severe consequence that occurs in the later stages of the disease due to sustained inflammation. However, the mechanism underlying SG fibrosis in SS remains under-investigated. Glandular fibrosis may arise from chronic sialadenitis, in which the interactions between infiltrating lymphocytes and epithelial cells potentially contributes to fibrotic pathogenesis. Thus, both immune and non-immune cells are closely involved in this process, while their interplays are not fully understood. The molecular mechanism of tissue fibrosis is partly associated with an imbalance of immune responses, in which the transforming growth factor-beta (TGF-β)-dependent epithelial-mesenchymal transition (EMT) and extracellular matrix remodeling are recently investigated. In addition, viral infection has been implicated in the pathogenesis of SS. Viral-specific innate immune response could exacerbate the autoimmune progression, resulting in overt inflammation in SG. Notably, post-COVID patients exhibit typical SS symptoms and severe inflammatory sialadenitis, which are positively correlated with SG damage. In this review, we discuss the immune and non-immune risk factors in SG fibrosis and summarize the evidence to understand the mechanisms upon autoimmune progression in SS.

The role of cytokines from salivary gland epithelial cells in the immunopathology of Sjögren's syndrome

In the pathogenesis and progression of Sjögren's syndrome (SS), hematopoietic cells in the peripheral circulation, tissue-resident immune cells, and parenchymal cells of salivary gland tissues (such as epithelial cells, endothelial cells, fibroblasts, etc.) all play crucial roles. These diverse cells form intricate networks and interact with each other, leading to tissue destruction and persistent chronic inflammation, ultimately causing irreversible damage in glandular function. Among these, salivary gland epithelial cells (SGECs) consistently hold a key position, characterized by their functions in expressing co-stimulatory and antigen-presenting molecules and secreting pro-inflammatory cytokines and chemokines. Moreover, SGECs actively engage in and facilitate the development of specific pathological structures within the salivary gland, such as lymphoepithelial lesions (LELs) and tertiary lymphoid structures (TLSs), thereby substantially elevating the risk of mucosa-associated lymphoid tissue (MALT) lymphoma. Overall, SGECs are recognized for their essential and irreplaceable contributions to the pathogenesis of SS. This review article initially delves into the anatomical composition of salivary gland epithelial cells, subsequently focusing on elucidating the different cytokines derived from SGECs, encompassing chemokines, pro-inflammatory cytokines, anti-inflammatory cytokines, pro-survival cytokines, and damage-associated molecular patterns (DAMPs), to explore their key roles in the pathogenesis of SS.

More severe parotid gland histopathology in paediatric-onset than in adult-onset Sjögren's disease

OBJECTIVES

The aim of this study was to assess the histopathological features of the parotid glands in patients with paediatric-onset Sjögren's disease (pedSjD) in comparison to patients with adult-onset Sjögren's disease (adSjD).

METHODS

This study was performed in Groningen, the Netherlands. Patients with pedSjD from a diagnostic paediatric cohort (n=19), patients with adSjD from a diagnostic adult cohort (n=32) and patients with adSjD who participated in a clinical trial (n=42) with a baseline parotid gland biopsy were included. Parotid gland biopsies were analysed after (immuno)histological staining for SjD-related histopathological markers and compared between groups.

RESULTS

All characteristic histopathological features of adSjD were also observed in pedSjD. There were no significant differences in lymphoepithelial lesions or immunoglobulin A (IgA)/IgG plasma cell shift between the pedSjD and the adSjD cohorts. However, compared with the diagnostic adSjD cohort (with comparable total EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) scores), pedSjD showed more severe lymphocytic infiltration as reflected by a higher focus score (p=0.003), a higher relative surface area of CD45+ infiltrate (p=0.041), higher numbers of B and T lymphocytes/mm2 (p=0.004 and p=0.029, respectively), a higher B/T lymphocyte ratio (p=0.013), higher numbers of CD21+ follicular dendritic cell networks/mm2 (p=0.029) and germinal centres (GC)/mm2 (p=0.002). Compared with the trial adSjD cohort, with significant higher total ESSDAI scores (p=0.001), only the B/T lymphocyte ratio and numbers of GC/mm2 were significantly higher in the pedSjD cohort (p=0.023 and p=0.018, respectively).

CONCLUSION

Patients with pedSjD exhibit more pronounced histopathological features compared with patients with adSjD at diagnosis. Notably, the histopathology of patients with pedSjD aligns more closely with that observed in an adSjD clinical trial cohort, with even stronger B lymphocyte involvement.

Increased Diagnostic Accuracy of the Labial Gland Biopsy in Primary Sjögren Syndrome When Multiple Histopathological Features Are Included

OBJECTIVE

The aim of this study was to evaluate the diagnostic accuracy of the labial salivary gland biopsy based on multiple histopathological features in patients with suspected primary Sjögren syndrome (pSS).

METHODS

Patients from a diagnostic sicca cohort with clinically suspected pSS who underwent a labial gland biopsy were included. Patients were categorized as having pSS or non-Sjögren syndrome sicca (non-SS sicca) based on vignettes scored by an expert panel. Labial gland biopsies were analyzed for the presence of four histopathological features: focus score (FS) ≥1, prelymphoepithelial and lymphoepithelial lesions, immunoglobulin G plasma cell shift, and germinal centers. Sensitivity and specificity of histologic features were calculated, and the optimal cutoff value for the number of histopathological features needed to diagnose pSS was determined with receiver operating curve analysis.

RESULTS

A total of 38 patients were categorized as having pSS and 65 as having non-SS sicca. In labial gland biopsies of patients with pSS, the prevalence of FS ≥1 was 82%, followed by 68% for pre-lymphoepithelial and lymphoepithelial lesions, 63% for plasma cell shift, and 24% for germinal centers. Although FS ≥1 showed the highest sensitivity for patients with pSS (82%), specificity was higher for the other three features (98%-100%). The presence of two or more (of four) histopathological features had almost comparable sensitivity to FS alone, but specificity increased with 12% to 100%. For fulfillment of American College of Rheumatology/EULAR criteria, specificity increased from 84% to 95% when an abnormal biopsy was defined by the presence of two or more histopathological features instead of FS ≥1 only.

CONCLUSION

The diagnostic accuracy of the labial gland biopsy increases when other histopathological features besides FS are taken into account, by reducing the number of false-positive biopsies.

cGAS-STING pathway expression correlates with genomic instability and immune cell infiltration in breast cancer

Genomic instability, as caused by oncogene-induced replication stress, can lead to the activation of inflammatory signaling, involving the cGAS-STING and JAK-STAT pathways. Inflammatory signaling has been associated with pro-tumorigenic features, but also with favorable response to treatment, including to immune checkpoint inhibition. In this study, we aim to explore relations between inflammatory signaling, markers of replication stress, and immune cell infiltration in breast cancer. Expression levels of cGAS-STING signaling components (STING, phospho-TBK1, and phospho-STAT1), replication stress markers (γH2AX and pRPA), replication stress-related proto-oncogenes (Cyclin E1 and c-Myc) and immune cell markers (CD20, CD4, and CD57) are determined immunohistochemically on primary breast cancer samples (n = 380). RNA-sequencing data from TCGA (n = 1082) and METABRIC (n = 1904) are used to calculate cGAS-STING scores. pTBK1, pSTAT1 expression and cGAS-STING pathway scores are all increased in triple-negative breast cancers compared to other subtypes. Expression of γH2AX, pRPA, Cyclin E1, c-Myc, and immune cell infiltration positively correlate with p-STAT1 expression (P < 0.001). Additionally, we observe significant positive associations between expression of pTBK1 and γH2AX, pRPA, c-Myc, and number of CD4+ cells and CD20+ cells. Also, cGAS-STING scores are correlated with genomic instability metrics, such as homologous recombination deficiency (P < 0.001) and tumor mutational burden (P < 0.01). Moreover, data from the I-SPY2 clinical trial (n = 71) confirms that higher cGAS-STING scores are observed in breast cancer patients who responded to immunotherapy combined with chemotherapy. In conclusion, the cGAS-STING pathway is highly expressed in TNBCs and is correlated with genomic instability and immune cell infiltration.