Salivary Gland Inflammation Research Articles

Increased expression of CXCL10 and CCL3 salivary gland chemokines in primary Sjögren's syndrome detected and systematically quantified using novel RNAscope® in situ hybridisation.

Primary Sjogren's syndrome is a chronic inflammatory disease characterised by the destruction of exocrine glands. We have previously shown significantly upregulated levels of CXCL10 and CCL3 chemokines in saliva from Sjogren's syndrome patients. In this study, we examined the expression pattern and localisation of these chemokines at the site of inflammation in patients' minor salivary glands using novel RNAscope® in situ hybridisation. Minor salivary glands from 33 primary Sjogren's syndrome patients and 22 non-Sjogren's syndrome sicca controls were included. The biopsies were formalin- fixed, paraffin-embedded and histopathologically evaluated. The CXCL10 and CCL3 mRNA expression in the glandular tissue was investigated using reverse transcription quantitative real-time polymerase chain reaction followed by RNAscope® in situ hybridisation. The mRNA expression of CXCL10 was higher than CCL3 in all patients. Significantly elevated expression of CXCL10 and CCL3 was detected in patients that also expressed autoantibody positivity and a positive biopsy for mononuclear cell infiltrates when compared to controls. CXCL10 was localised as clusters within focal infiltrates as well as adjacent to acinar and ductal epithelium, while CCL3 was expressed as scattered single mRNA molecules in focal infiltrates and in acinar cells. Our findings suggest CXCL10 as a possible disease biomarker in primary Sjogren's syndrome due to its upregulated expression in both saliva and minor salivary glands of patients and the localisation in the tissue. This should be re-assessed in a larger primary Sjogren's syndrome patient cohort, followed by additional functional studies to further validate its potential as a disease biomarker.

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.

Therapeutic JAK1 Inhibition Reverses Lupus Nephritis in a Mouse Model and Demonstrates Transcriptional Changes Consistent With Human Disease.

Janus kinase family members are essential for signaling by multiple cytokines, including many implicated in systemic lupus erythematosus (SLE) pathogenesis. To test whether inhibition of JAK1 signaling can be efficacious in SLE, we used a JAK1-selective inhibitor (ABT-317) and evaluated its ability to ameliorate disease in murine SLE. Efficacy of ABT-317 was evaluated using NZB/W-F1 mice treated prophylactically and therapeutically. Primary endpoints were proteinuria, survival, and saliva production. Other endpoints included histological analysis of kidneys and salivary glands, flow cytometric analysis of splenic cell populations, and gene expression analysis by RNA sequencing in the kidneys, salivary glands, and blood. Publicly available human kidney gene transcription data were used to assess the translatability of the mouse findings. ABT-317 was efficacious when dosed prophylactically and prevented disease for up to two months after treatment cessation. When dosed therapeutically, ABT-317 quickly reversed severe proteinuria and restored saliva production, as well as diminished kidney and salivary gland inflammation. ABT-317-induced changes in glomerular morphology coincided with normalization of a human nephrotic gene signature, suggesting translatability to human lupus nephritis (LN). JAK1 inhibition prevented and reversed kidney and salivary gland manifestations of murine lupus with long-lasting effects after treatment cessation. These data, along with the presence of JAK1 and nephrotic gene signatures in human LN glomeruli, suggest that a JAK1-selective inhibitor may be an effective therapeutic in the treatment of human SLE and LN.

Podoplanin expressing macrophages and their involvement in tertiary lymphoid structures in mouse models of Sjögren's disease.

Tertiary lymphoid structures (TLSs) are formed in tissues targeted by chronic inflammation processes, such as infection and autoimmunity. In Sjögren's disease, the organization of immune cells into TLS is an important part of disease progression. Here, we investigated the dynamics of tissue resident macrophages in the induction and expansion of salivary gland TLS. We induced Sjögren's disease by cannulation of the submandibular glands of C57BL/6J mice with LucAdV5. In salivary gland tissues from these mice, we analyzed the different macrophage populations prior to cannulation on day 0 and on day 2, 5, 8, 16 and 23 post-infection using multicolored flow cytometry, mRNA gene analysis, and histological evaluation of tissue specific macrophages. The histological localization of macrophages in the LucAdV5 induced inflamed salivary glands was compared to salivary glands of NZBW/F1 lupus prone mice, a spontaneous mouse model of Sjögren's disease. The evaluation of the dynamics and changes in macrophage phenotype revealed that the podoplanin (PDPN) expressing CX3CR1+ macrophage population was increased in the salivary gland tissue during LucAdV5 induced inflammation. This PDPN+ CX3CR1+ macrophage population was, together with PDPN+CD206+ macrophages, observed to be localized in the parenchyma during the acute inflammation phase as well as surrounding the TLS structure in the later stages of inflammation. This suggests a dual role of tissue resident macrophages, contributing to both proinflammatory and anti-inflammatory processes, as well as their possible interactions with other immune cells within the inflamed tissue. These macrophages may be involved with lymphoid neogenesis, which is associated with disease severity and progression. In conclusion, our study substantiates the involvement of proinflammatory and regulatory macrophages in autoimmune pathology and underlines the possible multifaceted functions of macrophages in lymphoid cell organization.

Metformin Attenuates Partial Epithelial-Mesenchymal Transition in Salivary Gland Inflammation via PI3K/Akt/GSK3β/Snail Signaling Axis.

Chronic inflammation in the salivary glands (SG) often triggers epithelial-mesenchymal transition (EMT), leading to the loss of acinar function and promoting fibrosis. This study explores the role of Metformin in mitigating partial EMT in SG inflammation. In vitro, human salivary gland epithelial cells (hSGECs) were treated with lipopolysaccharide (LPS) and Metformin. EMT markers and the PI3K/Akt/GSK3β/Snail signaling axis were assessed using RNA-seq and Western blot analysis. In vivo, a Wharton's duct ligation rat model was employed to mimic chronic sialadenitis (CS). Nine Wistar rats were randomly divided into three groups: Control, Ligation and Ligation + Metformin groups, with three rats per group. After ductal ligation, the Ligation + Metformin group received 100mg/kg of Metformin via intragastric administration, while the Control and Ligation groups received an equivalent saline every 24h. Histological analysis, immunohistochemical and immunofluorescence staining were conducted to evaluate acinar morphology, EMT, and the PI3K/Akt/GSK3β/Snail signaling axis. The results showed that in CS tissues, atrophied acinar cells underwent partial EMT. In vitro, Metformin reversed LPS-induced EMT in hSGECs. RNA-seq and Western blot revealed that Metformin achieved this effect by targeting the PI3K/Akt/GSK3β/Snail signaling axis (P < 0.01). In ductal ligation models, Metformin treatment restored ligation-induced acinar damage and functional loss (P < 0.01). Further histological evidence supported that Metformin mitigated EMT by inhibiting inflammatory activation of PI3K/Akt/GSK3β/Snail signaling axis (P < 0.01). In conclusion, Metformin alleviates partial EMT in SG inflammation by targeting the PI3K/Akt/GSK3β/Snail signaling axis, highlighting its potential as a therapeutic strategy for SG inflammation.

Oral manifestations of COVID-19 in children: a narrative literature review

COVID-19 triggers an acute inflammatory response in organs, tissues, tongue mucosa, and salivary glands. Some symptoms such as lesions on the tongue and oral mucosa, oral pseudomembranous candidiasis, pharyngitis, taste alteration, gingivitis, canker sores, and even multisystem inflammatory syndrome have been reported in children with COVID-19. Early diagnosis of oral manifestations improves patients' prognosis and quality of life. A narrative literature review was conducted based on studies published in PubMed and LiLacs from January 2020 to April 2024, related to oral manifestations in COVID-19 in children. Of the 68 articles found, 7 were selected after analysis. The main manifestations presented were: abscesses, mucositis, ulcerative lesions, gingivitis, pseudomembranous candidiasis, mucosal lesions, lip and tongue fissures, hemorrhagic crust, inflammation of salivary glands, lip swelling, and reactive infectious mucocutaneous eruption. The selected articles showed that these oral manifestations of COVID-19 can affect children in various age groups, serving as indicators of the disease and signs of worsening infection.

Syndecan-1 Plays a Role in the Pathogenesis of Sjögren's Disease by Inducing B-Cell Chemotaxis through CXCL13-Heparan Sulfate Interaction.

In Sjögren's disease (SjD), the salivary glandular epithelial cells can induce the chemotaxis of B cells by secreting B-cell chemokines such as C-X-C motif chemokine ligand 13 (CXCL13). Syndecan-1 (SDC-1) is a major transmembrane heparan sulfate proteoglycan (HSPG) predominantly expressed on epithelial cells that binds to and regulates heparan sulfate (HS)-binding molecules, including chemokines. We aimed to determine whether SDC-1 plays a role in the pathogenesis of SjD by acting on the binding of HS to B-cell chemokines. To assess changes in glandular inflammation and SDC-1 concentrations in the submandibular gland (SMG) and blood, female NOD/ShiLtJ and sex- and age-matched C57BL/10 mice were used. In the SMG of NOD/ShiLtJ mice, inflammatory responses were identified at 8 weeks of age, but increased SDC-1 concentrations in the SMG and blood were observed at 6 weeks of age, when inflammation had not yet started. As the inflammation of the SMG worsened, the SDC-1 concentrations in the SMG and blood increased. The expression of the CXCL13 and its receptor C-X-C chemokine receptor type 5 (CXCR5) began to increase in the SMG at 6 weeks of age and continued until 12 weeks of age. Immunofluorescence staining in SMG tissue and normal murine mammary gland cells confirmed the co-localization of SDC-1 and CXCL13, and SDC-1 formed a complex with CXCL13 in an immunoprecipitation assay. Furthermore, NOD/ShiLtJ mice were treated with 5 mg/kg HS intraperitoneally thrice per week for 6-10 weeks of age, and the therapeutic effects in the SMG were assessed at the end of 10 weeks of age. NOD/ShiLtJ mice treated with HS showed attenuated salivary gland inflammation with reduced B-cell infiltration, germinal center formation and CXCR5 expression. These findings suggest that SDC-1 plays a pivotal role in the pathogenesis of SjD by binding to CXCL13 through the HS chain.

A TNIP1-driven systemic autoimmune disorder with elevated IgG4

Whole-exome sequencing of two unrelated kindreds with systemic autoimmune disease featuring antinuclear antibodies with IgG4 elevation uncovered an identical ultrarare heterozygous TNIP1Q333P variant segregating with disease. Mice with the orthologous Q346P variant developed antinuclear autoantibodies, salivary gland inflammation, elevated IgG2c, spontaneous germinal centers and expansion of age-associated B cells, plasma cells and follicular and extrafollicular helper T cells. B cell phenotypes were cell-autonomous and rescued by ablation of Toll-like receptor 7 (TLR7) or MyD88. The variant increased interferon-β without altering nuclear factor kappa-light-chain-enhancer of activated B cells signaling, and impaired MyD88 and IRAK1 recruitment to autophagosomes. Additionally, the Q333P variant impaired TNIP1 localization to damaged mitochondria and mitophagosome formation. Damaged mitochondria were abundant in the salivary epithelial cells of Tnip1Q346P mice. These findings suggest that TNIP1-mediated autoimmunity may be a consequence of increased TLR7 signaling due to impaired recruitment of downstream signaling molecules and damaged mitochondria to autophagosomes and may thus respond to TLR7-targeted therapeutics.

Retroductal dexamethasone administration promotes the recovery from obstructive and inflammatory salivary gland dysfunction.

Salivary gland dysfunction, often resulting from salivary gland obstruction-induced inflammation, is a prevalent condition. Corticosteroid, known for its anti-inflammatory and immunomodulatory properties, is commonly prescribed in clinics. This study investigates the therapeutic implications and potential side effects of dexamethasone on obstructive sialadenitis recovery using duct ligation mice and salivary gland organoid models. Functional and pathological changes were assessed after administering dexamethasone to the duct following deligation 2 weeks after maintaining ligation of the mouse submandibular duct. Additionally, lipopolysaccharide- and tumor necrosis factor-induced salivary gland organoid inflammation models were established to investigate the effects and underlying mechanisms of action of dexamethasone. Dexamethasone administration facilitated SG function restoration, by increasing salivary gland weight and saliva volume while reducing saliva lag time. Histological evaluation revealed, reduced acinar cell atrophy and fibrosis with dexamethasone treatment. Additionally, dexamethasone suppressed pro-inflammatory cytokines IL-1β and TNF expression. In a model of inflammation in salivary gland organoids induced by inflammatory substances, dexamethasone restored acinar markers such as AQP5 gene expression levels, while inhibiting pro-inflammatory cytokines TNF and IL6, as well as chemokines CCL2, CXCL5, and CXCL12 induction. Macrophages cultured in inflammatory substance-treated media from salivary gland organoid cultures exhibited pro-inflammatory polarization. However, treatment with dexamethasone shifted them towards an anti-inflammatory phenotype by reducing M1 markers (Tnf, Il6, Il1b, and Cd86) and elevating M2 markers (Ym1, Il10, Cd163, and Klf4). However, high-dose or prolonged dexamethasone treatment induced acino-ductal metaplasia and had side effects in both in vivo and in vitro models. Our findings suggest the effectiveness of corticosteroids in treating obstructive sialadenitis-induced salivary gland dysfunction by regulating pro-inflammatory cytokines.

Hyposalivation in patients with psoriasis: Association with severity, inflammatory, and anti-inflammatory cytokine biomarkers of the disease.

The aim of the study is to expound the effect of psoriasis on salivary glands by evaluating the secretion of saliva and salivary cytokine biomarkers in patients with psoriasis. This study was conducted by recruiting 120 subjects that included 60 patients diagnosed clinically with active psoriasis and 60 healthy controls who were age and gender matched to psoriatic subjects. Unstimulated whole saliva was collected from all the subjects by spitting method, and levels of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukin-2 (IL-2), and IL-10 (IL-10) were determined via enzyme-linked immunosorbent assay (BT Lab, Shanghai, China). Secretion of saliva in psoriasis patients was considerably reduced than in healthy controls. The concentrations of pro-inflammatory cytokines (TNF-α, IFN-γ, and IL-2) were significantly increased, whereas level of anti-inflammatory cytokine (IL-10) was markedly decreased in the saliva of psoriasis patients with hyposalivation compared to healthy subjects. Our results demonstrated significant negative correlation of salivary flow rates with the disease severity. No significant correlations were obtained between salivary levels of tested cytokines and salivary flow rates in our study. Findings of the study reflect inflammation of salivary glands with reduced salivary flow rates in psoriasis patients. The inflammatory responses in salivary gland tissues by virtue of increased pro-inflammatory cytokines concentrations together with lower anti-inflammatory cytokine levels may have a role in affecting the saliva secretion in psoriasis patients. Secretion of unstimulated saliva in psoriasis patients decreases with the severity and duration of the disease.

IL-27 promotes pathogenic T cells in a mouse model of Sjögren's disease

Sjögren's disease (SjD) is a chronic autoimmune disease characterized by focal lymphocytic inflammation in lacrimal and salivary glands. We recently identified IL-27 as a requisite signal for the spontaneous SjD-like manifestations in nonobese diabetic (NOD) mice. Here, we define T cell-intrinsic effects of IL-27 in lacrimal gland disease in NOD mice. IL-27 receptor was required by both CD4 T effector (Te) cells and CD8 T cells to mediate focal inflammation. Intrinsic IL-27 signaling was associated with PD-1 and ICOS expressing T follicular helper (Tfh)-like CD4 Te cells within lacrimal glands, including subsets defined by CD73 or CD39 expression. CD8 T cells capable of IL-27 signaling also expressed PD-1 with subsets expressing ICOS and CD73 demonstrating a T follicular cytotoxic (Tfc)-like cell phenotype and others expressing a CD39hi exhausted-like phenotype. These findings suggest IL-27 is a key early signal driving a follicular-type response in lacrimal gland inflammation in NOD mice.

Age-associated B cell infiltration in salivary glands represents a hallmark of Sjögren's-like disease in aging mice.

Sjögren's disease (SjD), characterized by circulating autoantibodies and exocrine gland inflammation, is typically diagnosed in women over 50years of age. However, the contribution of age to SjD pathogenesis is unclear. C57BL/6 female mice at different ages were studied to investigate how aging influences the dynamics of salivary gland inflammation. Salivary glands were characterized for immune cell infiltration, inflammatory gene expression, and saliva production. At 8months, gene expression of several chemokines involved in immune cell trafficking was significantly elevated. At this age, age-associated B cells (ABCs), a unique subset of B cells expressing the myeloid markers CD11b and/or CD11c, were preferentially enriched in the salivary glands compared to other organs like the spleen or liver. The salivary gland ABCs increased with age and positively correlated with increased CD4 T follicular helper cells. By 14months, lymphocytic foci of well-organized T and B cells spontaneously developed in the salivary glands. In addition, the mice progressively developed high titers of serum autoantibodies. A subset of aged mice developed salivary gland dysfunction mimicking SjD patients. Our data demonstrates that aging is a significant confounding factor for SjD. Thus, aged female C57BL/6 mice are more appropriate and a valuable preclinical model for investigating SjD pathogenesis and novel therapeutic interventions.

Inhibition of JAK-STAT pathway corrects salivary gland inflammation and interferon driven immune activation in Sjögren’s disease

ObjectivesInflammatory cytokines that signal through the Janus kinases–signal transducer and activator of transcription (JAK-STAT) pathway, especially interferons (IFNs), are implicated in Sjögren’s disease (SjD). Although inhibition of JAKs is effective...

Imaging of the Posttreatment Head and Neck: Expected Findings and Potential Complications.

Interpretation of posttreatment imaging findings in patients with head and neck cancer can pose a substantial challenge. Malignancies in this region are often managed through surgery, radiation therapy, chemotherapy, and newer approaches like immunotherapy. After treatment, patients may experience various expected changes, including mucositis, soft-tissue inflammation, laryngeal edema, and salivary gland inflammation. Imaging techniques such as CT, MRI, and PET scans help differentiate these changes from tumor recurrence. Complications such as osteoradionecrosis, chondroradionecrosis, and radiation-induced vasculopathy can arise because of radiation effects. Radiation-induced malignancies may occur in the delayed setting. This review article emphasizes the importance of posttreatment surveillance imaging to ensure proper care of patients with head and neck cancer and highlights the complexities in distinguishing between expected treatment effects and potential complications. Keywords: CT, MR Imaging, Radiation Therapy, Ear/Nose/Throat, Head/Neck, Nervous-Peripheral, Bone Marrow, Calvarium, Carotid Arteries, Jaw, Face, Larynx © RSNA, 2024.

Identification of Key Genes for Pyroptosis-Induced Salivary Gland Inflammation in Sjogren’s Syndrome Based on Microarray Data and Immunohistochemistry Analysis

Identification of Key Genes for Pyroptosis-Induced Salivary Gland Inflammation in Sjogren’s Syndrome Based on Microarray Data and Immunohistochemistry Analysis

Network pharmacology identifies the inhibitory effect of Yiqiyangyinquyu prescription on salivary gland inflammation in Sjögren's syndrome.

This study aimed to explore the mode of action of Yiqiyangyinquyu prescription (YP) against Sjögren's syndrome (SS) by combining network pharmacology with molecular docking techniques. YP's active components and target proteins were identified using the BATMAN-traditional Chinese medicine database. Concurrently, targets associated with SS were extracted from databases, including Genecards, Online Mendelian Inheritance in Man, and Therapeutic Target Database. The standard targets were then imported into the STRING database to construct a protein-protein interaction network. We then conducted gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses, which were succeeded by molecular docking studies to validate core active components and key targets. Finally, in vitro experiments and molecular dynamics simulation were conducted to substantiate the therapeutic efficacy of YP in treating SS. A total of 206 intersection targets and 46 active compounds were identified. Gene ontology analysis unveiled that YP targets were primarily enriched in cellular responses to chemical stress, inflammation, and cell proliferation. Key enriched signaling pathways encompassed the interleukin 17, hypoxia-inducible factor-1, tumor necrosis factor (TNF-α), and advanced glycation end products-receptor for AGEs (AGE-RAGE) signaling pathways. Molecular docking results demonstrated high-affinity between neotanshinone C, tanshiquinone B, miltionone I, TNF-α, interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). Noteworthy, TNF-α, considered the most important gene in YP against SS, binds to YP most stably, which was further validated by molecular dynamics simulation. In vitro experiments confirmed YP's capacity to reduce TNF-α, IL-1β, and IL-6 expression, effectively alleviating SS-related inflammation. YP demonstrated a significant anti-inflammatory effect by suppressing inflammatory cytokines (TNF-α, IL-6, and IL-1β), providing experimental evidence for its clinical application in treating SS.

Unusual upper lip swelling: A review and a case report of cheilitis landularis

Cheilitis glandularis (CG) is a rare inflammatory condition characterized by chronic enlargement and inflammation of the minor salivary glands in the lip. This article provides a comprehensive review of CG, including its clinical features, subtypes, and potential predisposing factors. Additionally, a case report is presented to illustrate the diagnostic challenges and management strategies associated with this uncommon disorder. CG primarily affects the lower lip, leading to symptoms such as lip swelling, persistent inflammation, dryness, and ulceration. While the exact etiology remains elusive, factors such as infections, obstructions, and autoimmune processes are believed to play a role in CG development. Although the exact relationship is not well-established, stress and psychological factors may influence immune functioning and contribute to the exacerbation or recurrence of inflammatory conditions, including CG. The case report highlights an unusual upper lip swelling that was diagnosed as CG. This underscores the importance of thorough clinical examination, differential diagnosis, and histopathological evaluation in accurately identifying CG. Timely recognition and appropriate management are essential for optimizing patient outcomes and preventing potential complications. In conclusion, CG presents a diagnostic challenge due to its diverse clinical presentation. Clinicians should maintain a high index of suspicion when encountering lip swelling and consider CG in the differential diagnosis. Further research is needed to elucidate the underlying mechanisms and potential predisposing factors associated with CG, including the role of mental health. Increased awareness and understanding of this condition will facilitate early detection, appropriate management, and improved outcomes for individuals affected by CG.

Shikonin ameliorates salivary gland damage and inflammation in a mouse model of Sjögren’s syndrome by modulating MAPK signaling pathway

Shikonin ameliorates salivary gland damage and inflammation in a mouse model of Sjögren’s syndrome by modulating MAPK signaling pathway

Ductal delivery of extracellular vesicles promote the recovery from salivary gland inflammation

Salivary gland dysfunction worsens the quality of life, but treatment for restoration of salivary gland function is limited. Although previous reports have demonstrated the therapeutic potentials of extracellular vesicles (EVs) in different preclinical models, the role of EVs in salivary glands remains elusive. Furthermore, little is known about the roles of salivary gland-derived EVs in tissue repair or regeneration compared to other EVs. In this study, EVs secreted from salivary gland-derived mesenchymal stem cells (sgMSCs) were comparatively analyzed with those from Wharton's jelly-derived MSC (wjMSCs). sgMSCs secreted more significant amounts of EVs than wjMSCs, and salivary gland epithelial cells showed a more efficient uptake of sgMSC-EVs than wjMSC-EVs. The possibility of immune regulation was tested via macrophage polarization and LPS-induced epithelial inflammation, resulting in an M1-to-M2 shift and reversal of acinar-to-ductal metaplasia by sgMSC-EV. Furthermore, the roles of sgMSC-EV-mediated immune regulation and tissue repair were clarified in vivo via retroductal delivery of sgMSC-EVs in a mouse model of obstructive sialadenitis. Collectively, our data demonstrate the superior role of sgMSC-EVs in the recovery from salivary gland inflammation and injury and suggest EVs as therapeutic tools for salivary gland dysfunction.

Lymphoma-associated mutations in autoreactive memory B cells of patients with Sjögren's syndrome.

We recently demonstrated that normal memory B lymphocytes carry a substantial number of de novo mutations in the genome. Here, we performed exome-wide somatic mutation analyses of bona fide autoreactive rheumatoid factor (RF)-expressing memory B cells retrieved from patients with Sjӧgren's syndrome (SS). The amount and repertoire of the de novo exome mutations of RF B cells were found to be essentially different from those detected in healthy donor memory B cells. In contrast to the mutation spectra of normal B cells, which appeared random and non-selected, the mutations of the RF B cells were greater in number and enriched for mutations in genes also found mutated in B-cell non-Hodgkin lymphomas. During the study, one of the SS patients developed a diffuse large B-cell lymphoma (DLBCL) out of an RF clone that was identified 2 years earlier in an inflamed salivary gland biopsy. The successive oncogenic events in the RF precursor clone and the DLBCL were assessed. In conclusion, our findings of enhanced and selected genomic damage in growth-regulating genes in RF memory B cells of SS patients together with the documented transformation of an RF-precursor clone into DLBCL provide unique novel insight into the earliest stages of B-cell derailment and lymphomagenesis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.