TREX1 variants in Sjogren's syndrome related lymphomagenesis

Vitamin D in Primary Sjogren's Syndrome (pSS) and the Identification of Novel Single-Nucleotide Polymorphisms Involved in the Development of pSS-Associated Diseases

Sjögren's syndrome (SS) is a chronic autoimmune disorder characterised by lymphocytic infiltration of the exocrine glands, which leads to dryness of the eyes and mouth; systemic manifestations such as arthritis, vasculitis, and interstitial lung disease; and increased risks of lymphoma and cardiovascular diseases. SS predominantly affects women, with a strong genetic component linked to sex chromosomes. Genome-wide association studies (GWASs) have identified numerous single-nucleotide polymorphisms (SNPs) associated with primary SS (pSS), revealing insights into its pathogenesis. The adaptive and innate immune systems are crucial to SS's development, with viral infections implicated as environmental triggers that exacerbate autoimmune responses in genetically susceptible individuals. Moreover, recent research has highlighted the role of vitamin D in modulating immune responses in pSS patients, suggesting its potential therapeutic implications. In this review, we focus on the recently identified SNPs in genes like OAS1, NUDT15, LINC00243, TNXB, and THBS1, which have been associated with increased risks of developing more severe symptoms and other diseases such as fatigue, lymphoma, neuromyelitis optica spectrum disorder (NMOSD), dry eye syndrome (DES), and adverse drug reactions. Future studies should focus on larger, multi-ethnic cohorts with standardised protocols to validate findings and identify new associations. Integrating genetic testing into clinical practise holds promise for improving SS management and treatment strategies, enabling personalised interventions based on comprehensive genetic profiles. By focusing on specific SNPs, vitamin D, and their implications, future research can lead to more effective and personalised approaches for managing pSS and its complications.

The Expression Levels of TREX1 and IFN-α Are Associated with Immune Reconstitution in HIV-1-Infected Individuals

TREX1 acts in the initial prevention of an autoimmune response, but it may contribute to the permissiveness of retrovirus infections. This study investigated the association between the levels of TREX1 gene expression with the polymorphisms TREX1 rs3135941 (T/C) and TREX1 rs3135945 (G/A), and the presence of antinuclear antibodies (ANA) in antiretroviral therapy (ART)-naïve individuals and after 1 year of treatment. Blood samples from 119 individuals with HIV-1 were subjected to genotyping of polymorphisms and quantification of TREX1 gene expression and HIV-1 viral load by qPCR. The concentration of IFN-α and the number of CD4+/CD8+ T lymphocytes were determined by ELISA and flow cytometry, respectively; ANA was investigated by immunofluorescence. A control group of 167 seronegative individuals was used for the comparison of genotypic frequencies. The frequency of the polymorphisms were not associated with HIV infection or with variations in the expression of TREX1 and IFN-α (p > 0.05). ART-naïve individuals exhibited higher TREX1 expression and lower IFN-α expression. After 1 year of ART, TREX1 levels were reduced, while IFN-α and CD4+ T lymphocytes were elevated (p < 0.05). Some individuals on ART presented ANA. These results suggest that ART-mediated restoration of immune competence is associated with a reduction in TREX1 expression, which may induce the development of ANA, regardless of the polymorphism investigated.

Chronic Epstein-Barr virus infection: A potential junction between primary Sjögren's syndrome and lymphoma

Primary Sjögren's syndrome (pSS) is an autoimmune disease that targets exocrine glands, leading to exocrine dysfunction. Due to its propensity to infect epithelial and B cells, Epstein-Barr virus (EBV) is hypothesized to be related with pSS. Through molecular mimicry, the synthesis of specific antigens, and the release of inflammatory cytokines, EBV contributes to the development of pSS. Lymphoma is the most lethal outcome of EBV infection and the development of pSS. As a population-wide virus, EBV has had a significant role in the development of lymphoma in people with pSS. In the review, we will discuss the possible causes of the disease.

Potential health risks of mRNA-based vaccine therapy: A hypothesis

Therapeutic applications of synthetic mRNA were proposed more than 30 years ago, and are currently the basis of one of the vaccine platforms used at a massive scale as part of the public health strategy to get COVID-19 under control. To date, there are no published studies on the biodistribution, cellular uptake, endosomal escape, translation rates, functional half-life and inactivation kinetics of synthetic mRNA, rates and duration of vaccine-induced antigen expression in different cell types. Furthermore, despite the assumption that there is no possibility of genomic integration of therapeutic synthetic mRNA, only one recent study has examined interactions between vaccine mRNA and the genome of transfected cells, and reported that an endogenous retrotransposon, LINE-1 is unsilenced following mRNA entry to the cell, leading to reverse transcription of full length vaccine mRNA sequences, and nuclear entry. This finding should be a major safety concern, given the possibility of synthetic mRNA-driven epigenetic and genomic modifications arising. We propose that in susceptible individuals, cytosolic clearance of nucleotide modified synthetic (nms-mRNAs) is impeded. Sustained presence of nms-mRNA in the cytoplasm deregulates and activates endogenous transposable elements (TEs), causing some of the mRNA copies to be reverse transcribed. The cytosolic accumulation of the nms-mRNA and the reverse transcribed cDNA molecules activates RNA and DNA sensory pathways. Their concurrent activation initiates a synchronized innate response against non-self nucleic acids, prompting type-I interferon and pro-inflammatory cytokine production which, if unregulated, leads to autoinflammatory and autoimmune conditions, while activated TEs increase the risk of insertional mutagenesis of the reverse transcribed molecules, which can disrupt coding regions, enhance the risk of mutations in tumour suppressor genes, and lead to sustained DNA damage. Susceptible individuals would then expectedly have an increased risk of DNA damage, chronic autoinflammation, autoimmunity and cancer. In light of the current mass administration of nms-mRNA vaccines, it is essential and urgent to fully understand the intracellular cascades initiated by cellular uptake of synthetic mRNA and the consequences of these molecular events.

Predisposing Factors, Clinical Picture, and Outcome of B-Cell Non-Hodgkin’s Lymphoma in Sjögren’s Syndrome

Among other systemic autoimmune diseases, primary Sjögren syndrome (pSS) bears the highest risk for lymphoma development. In pSS, chronic antigenic stimulation gradually drives the evolution from polyclonal B-cell expansion to oligoclonal/monoclonal B-cell predominance to malignant B-cell transformation. Thus, most pSS-related lymphomas are B-cell non-Hodgkin lymphomas (NHLs), with mucosa-associated lymphoid tissue (MALT) lymphomas predominating, followed by diffuse large B-cell lymphomas (DLBCLs) and nodal marginal zone lymphomas (NMZLs). Since lymphomagenesis is one of the most serious complications of pSS, affecting patients’ survival, a plethora of possible predisposing factors has been studied over the years, ranging from classical clinical, serological, hematological, and histological, to the more recently proposed genetic and molecular, allowing clinicians to timely detect and to closely follow-up the subgroup of pSS patients with increased risk for lymphoma development. Overall predisposing factors for pSS-related lymphomagenesis reflect the status of B-cell hyperactivity. Different clinical features have been described for each of the distinct pSS-related B-cell NHL subtypes. While generally pSS patients developing B-cell NHLs display a fairly good prognosis, outcomes in terms of treatment response and survival rates seem to differ depending on the lymphoma subtype, with MALT lymphomas being characterized by a rather indolent course and DLBCLs gravely affecting patients’ survival.

JAK/STAT Pathway Targeting in Primary Sjögren Syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune systemic disease mainly affecting exocrine glands and resulting in disabling symptoms, as dry eye and dry mouth. Mechanisms underlying pSS pathogenesis are intricate, involving multiplanar and, at the same time, interlinked levels, e.g., genetic predisposition, epigenetic modifications and the dysregulation of both immune system and glandular-resident cellular pathways, mainly salivary gland epithelial cells. Unravelling the biological and molecular complexity of pSS is still a great challenge but much progress has been made in recent years in basic and translational research field, allowing the identification of potential novel targets for therapy development. Despite such promising novelties, however, none therapy has been specifically approved for pSS treatment until now. In recent years, growing evidence has supported the modulation of Janus kinases (JAK) - signal transducers and activators of transcription (STAT) pathways as treatment strategy immune mediated diseases. JAK-STAT pathway plays a crucial role in autoimmunity and systemic inflammation, being involved in signal pathways of many cytokines. This review aims to report the state-of-the-art about the role of JAK-STAT pathway in pSS, with particular focus on available research and clinical data regarding the use of JAK inhibitors in pSS.

Biomarkers of lymphoma in Sjögren's syndrome: what's the latest?

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease standing in the crossroads of autoimmunity and lymphomagenesis, characterized by chronic B-cell hyperactivity and ectopic lymphoid tissue neoformation, potentially driving lymphoid malignant transformation. Lymphoma development is considered the most serious complication of pSS.

AREAS COVERED: “

Old-classical" biomarkers (clinical, serological, hematological, and histological) validated in the past are analyzed under the perspective of recently published research. Biomarkers that have emerged during the last decade are subdivided to "old-new" and "newly proposed-novel" ones, including biomarkers pathophysiologically related to B-cell differentiation, lymphoid organization, and immune responses, identified in serum and tissue, both at genetic and protein level. Upcoming new imaging biomarkers, promising for further patient stratification, are also analyzed.

EXPERT OPINION

Salivary gland enlargement and cryoglobulinemia still remain the best validated "classical-old" biomarkers for lymphoma development. Though new biomarkers still need to be validated, some can be used for the identification of high-risk patients long before lymphoma diagnosis, some might be more relevant in distinct age subgroups, while others have an added value in the assessment of lymphoma remission or relapse. Future development of composite indices integrating old and recently proposed biomarkers could contribute to a more precise lymphoma prediction model.

Type I interferon detection in autoimmune diseases: challenges and clinical applications

INTRODUCTION

Accumulating data highlights that the dysregulation of type I interferon (IFN) pathways plays a central role in the pathogenesis of several systemic and organ-specific autoimmune diseases. Advances in understanding the role of type I IFNs in these disorders can lead to targeted drug development as well as establishing potential disease biomarkers.

AREAS COVERED

Here, we summarize current knowledge regarding the role of type I IFNs in the major systemic, as well as organ-specific, autoimmune disorders, including prominent inflammatory CNS disorders like multiple sclerosis.

EXPERT OPINION

Type I IFN involvement and its clinical associations in a wide spectrum of autoimmune diseases represents a promising area for research aiming to unveil common pathogenetic pathways in systemic and organ-specific autoimmunity.

Interferon (IFN)-stimulated gene 15: A novel biomarker for lymphoma development in Sjögren's syndrome

OBJECTIVE

We investigated whether interferon (IFN) induced genes could serve as biomarkers for the detection of lymphoma development among patients with Sjögren's syndrome (SS).

METHODS

Total RNA was extracted from 98 labial minor salivary glands (LMSG) biopsies of SS patients [61 not complicated by lymphoma (SS-nL) and 37 complicated by Non-Hodgkin Lymphoma (NHL) (SS-L)] and 67 matched peripheral blood (PB) samples, as well as from 30 LMSG biopsies and 17 matched PB derived from sicca controls (SC). RNA sequencing was performed in LMSG biopsies of high and low risk SS patients for lymphoma development and SC. Expression analysis of type I (MX-1, IFIT-1, IFI44 and ISG-15) and type II IFN induced (CXCL9/MIG-1, GBP-1) genes was performed by real time PCR.

RESULTS

ISG-15 transcript levels were significantly higher in SS-L patients compared to SS-nL patients in both LMSG tissues and PB specimens. Additionally, MIG-1 was found to display higher expression values in LMSG tissues, but not in PB derived from SS-L patients compared to the SS-nL group. A coordinate expression in PB/LMSG of type I IFN (ISG-15, MX-1 and IFI44), but not type II IFN induced genes was also observed.

CONCLUSION

ISG-15 gene expression was able to distinguish SS-nL and SS-L at both periphery and tissue level and therefore could represent a novel biomarker for lymphoma development among SS patients. PB and LSMG seem to share a common transcriptional profile of type I IFN pathway.

Lipoprotein-Associated Phospholipase A2: A Novel Contributor in Sjögren's Syndrome-Related Lymphoma?

Background

B-cell non-Hodgkin’s lymphoma (B-NHL) is one of the major complications of primary Sjögren’s syndrome (SS). Chronic inflammation and macrophages in SS minor salivary glands have been previously suggested as significant predictors for lymphoma development among SS patients. Lipoprotein-associated phospholipase A2 (Lp-PLA2)—a product mainly of tissue macrophages—is found in the circulation associated with lipoproteins and has been previously involved in cardiovascular, autoimmune, and malignant diseases, including lymphoma.

Objective

The purpose of the current study was to investigate the contributory role of Lp-PLA2 in B-NHL development in the setting of primary SS.

Methods

Lp-PLA2 activity in serum samples collected from 50 primary SS patients with no lymphoma (SS-nL), 9 primary SS patients with lymphoma (SS-L), and 42 healthy controls (HC) was determined by detection of [³H]PAF degradation products by liquid scintillation counter. Moreover, additional sera from 50 SS-nL, 28 SS-L, and 32 HC were tested for Lp-PLA2 activity using a commercially available ELISA kit. Lp-PLA2 mRNA, and protein expression in minor salivary gland (MSG) tissue samples derived from SS-nL, SS-L patients, and sicca controls (SC) were analyzed by real-time PCR, Western blot, and immunohistochemistry.

Results

Serum Lp-PLA2 activity was significantly increased in SS-L compared to both SS-nL and HC by two independent methods implemented [mean ± SD (nmol/min/ml): 62.0 ± 13.4 vs 47.6 ± 14.4 vs 50.7 ± 16.6, p-values: 0.003 and 0.04, respectively, and 19.4 ± 4.5 vs 15.2 ± 3.3 vs 14.5 ± 3.0, p-values: <0.0001, in both comparisons]. ROC analysis revealed that the serum Lp-PLA2 activity measured either by radioimmunoassay or ELISA has the potential to distinguish between SS-L and SS-nL patients (area under the curve [AUC]: 0.8022, CI [95%]: 0.64–0.96, p-value: 0.004 for radioimmunoassay, and AUC: 0.7696, CI [95%]: 0.66–0.88, p-value: <0.0001, for ELISA). Lp-PLA2 expression in MSG tissues was also increased in SS-L compared to SS-nL and SC at both mRNA and protein level. ROC analysis revealed that both MSG mRNA and protein Lp-PLA2 have the potential to distinguish between SS-nL and SS-L patients (area under the curve [AUC] values of 0.8490, CI [95%]: 0.71–0.99, p-value: 0.0019 and 0.9444, CI [95%]: 0.79–1.00, p- value: 0.0389 respectively). No significant difference in either serum Lp-PLA2 activity or MSG tissue expression was observed between SS-nL and HC.

Conclusions

Lp-PLA2 serum activity and MSG tissue mRNA/protein expression could be a new biomarker and possibly a novel therapeutic target for B-cell lymphoproliferation in the setting of SS.

Lymphomagenesis predictors and related pathogenesis

Sjögren's syndrome (SS) is a systemic autoimmune disease characterised by a wide range of clinical manifestations and complications, including B-cell lymphoma. This study aims to describe the predictors associated with lymphomagenesis in patients with Sjögren's syndrome, emphasising the pathophysiological bases that support this association. We performed a review of the literature published through a comprehensive search strategy in PubMed/MEDLINE, Scopus, and Web of science. Forty publications describing a total of 45,208 patients with SS were retrieved. The predictors were grouped according to their pathophysiological role in the lymphoproliferation process. Also, some new biomarkers such as MicroRNAs, P2X7 receptor-NLRP3 inflammasome, Thymic stromal lymphopoietin, and Three-prime repair exonuclease 1 (TREX1) were identified. The knowledge of the pathophysiology allows the discrimination of markers that participate in the initial stages. Considering that the lymphoproliferation process includes the progression of lymphoma towards more aggressive subtypes, it is essential to recognise biomarkers associated with a worse prognosis.

Leukocyte Immunoglobulin-Like Receptor A3 (LILRA3): A Novel Marker for Lymphoma Development among Patients with Young Onset Sjogren's Syndrome

Background: Primary Sjogren’s syndrome (SS) is an autoimmune disease with a strong predilection for lymphoma development, with earlier disease onset being postulated as an independent risk factor for this complication. Variations of the Leukocyte immunoglobulin-like receptor A3(LILRA3) gene have been previously shown to increase susceptibility for both SS and non-Hodgkin B-cell lymphoma (B-NHL) in the general population. We aimed to investigate whether variations of the LILRA3 gene could predispose for lymphoma development in the context of SS. Methods: Study population, all of Greek origin, included 101 SS cases with a current or previous diagnosis of lymphoma (SS-lymphoma, SS-L) and 301 primary SS patients not complicated by lymphoma (SS-non-lymphoma, SS-nL). All SS patients fulfilled the 2016 SS American College of Rheumatology/European league against Rheumatism (ACR/EULAR) classification criteria. A total of 381 healthy controls (HC) of similar age/sex/race distribution were also included. On the basis of the age of SS onset and the presence or absence of adverse predictors for lymphoma development, SS patients were further stratified into younger (≤40 years) and older (>40 years) age of disease onset, as well as into high/medium and low risk groups. Polymerase chain reaction (PCR) was implemented for the detection of the following LILRA3 gene variants: homozygous non-deleted or functional wild type (+/+) heterozygous (+/−) and homozygous deleted (−/−). LILRA3 serum protein levels were quantitated by enzyme-linked immunosorbent assay (ELISA) in 85 individuals (29 SS-L, 35 SS-nL patients and 21 HC). Results: While no statistically significant differences were detected in the overall frequency of LILRA3 gene variants between SS-L, SS-nL and HC groups, LILRA3 serum protein levels were increased in the SS-L group compared to HC (1.27 ± 1.34 vs. 0.38 ± 0.34 ng/mL, p-value: 0.004). After stratification according to the age of SS onset and history of lymphoma, as well as the presence or absence of adverse predictors for lymphoma development, the prevalence of the functional LILRA3 gene variant was found to be significantly increased in the young onset SS-L group compared to the HC of similar age and sex distribution (100% vs. 82.9%, p = 0.03), as well as in the high/medium risk SS compared to the low risk SS (91.3 vs. 78.3%, p = 0.0012). Of note, young onset SS-L and SS-nL groups displayed higher LILRA3 serum levels compared to their older counterparts (p-values: 0.007 and 0.0005, respectively). Conclusion: The functional LILRA3 gene variant increases susceptibility to SS-related lymphoma development in patients with a disease onset of <40 years old, implying that genetically determined deranged immune responses in younger SS individuals could underly their pronounced risk for lymphoma development.

Making Sense of Intracellular Nucleic Acid Sensing in Type I Interferon Activation in Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a systemic autoimmune rheumatic disease characterized by dryness of the eyes and mucous membranes, which can be accompanied by various extraglandular autoimmune manifestations. The majority of patients exhibit persistent systemic activation of the type I interferon (IFN) system, a feature that is shared with other systemic autoimmune diseases. Type I IFNs are integral to anti-viral immunity and are produced in response to stimulation of pattern recognition receptors, among which nucleic acid (NA) receptors. Dysregulated detection of endogenous NAs has been widely implicated in the pathogenesis of systemic autoimmune diseases. Stimulation of endosomal Toll-like receptors by NA-containing immune complexes are considered to contribute to the systemic type I IFN activation. Accumulating evidence suggest additional roles for cytosolic NA-sensing pathways in the pathogenesis of systemic autoimmune rheumatic diseases. In this review, we will provide an overview of the functions and signaling of intracellular RNA- and DNA-sensing receptors and summarize the evidence for a potential role of these receptors in the pathogenesis of pSS and the sustained systemic type I IFN activation.

Novel insights on lymphoma and lymphomagenesis in primary Sjögren's Syndrome

Primary Sjögren's Syndrome (pSS) is a systemic autoimmune disease characterized by a chronic inflammatory process mainly affecting the exocrine glands but also burdened by a wide range of extraglandular manifestations. Non-Hodgkin lymphoma (NHL) is the most severe pSS complication worsening disease prognosis. We summarized original articles published between April 2018 and May 2020 on this topic aiming to highlight novelties on lymphoma and lymphomagenesis. Results have been grouped by epidemiology, etiopathogenesis and predictors of lymphoma. NHL is the most severe complication of pSS and occurs in around 5-10% of patients. Over the last two years, several clinical, serological, and histopathological features have been proposed as predictive for lymphoma in pSS patients, allowing early diagnosis and consequently, better management and prognosis. Individual monitoring for disease activity and possible lymphoma development is a central clue in the evaluation of pSS patients.

Predicting Lymphoma Development by Exploiting Genetic Variants and Clinical Findings in a Machine Learning-Based Methodology With Ensemble Classifiers in a Cohort of Sjögren's Syndrome Patients

Lymphoma development constitutes one of the most serious clinico-pathological manifestations of patients with Sjögren's Syndrome (SS). Over the last decades the risk for lymphomagenesis in SS patients has been studied aiming to identify novel biomarkers and risk factors predicting lymphoma development in this patient population. Objective: The current study aims to explore whether genetic susceptibility profiles of SS patients along with known clinical, serological and histological risk factors enhance the accuracy of predicting lymphoma development in this patient population. Methods: The potential predicting role of both genetic variants, clinical and laboratory risk factors were investigated through a Machine Learning-based (ML) framework which encapsulates ensemble classifiers. Results: Ensemble methods empower the classification accuracy with approaches which are sensitive to minor perturbations in the training phase. The evaluation of the proposed methodology based on a 10-fold stratified cross validation procedure yielded considerable results in terms of balanced accuracy (GB: 0.7780 ± 0.1514, RF Gini: 0.7626 ± 0.1787, RF Entropy: 0.7590 ± 0.1837). Conclusions: The initial clinical, serological, histological and genetic findings at an early diagnosis have been exploited in an attempt to establish predictive tools in clinical practice and further enhance our understanding towards lymphoma development in SS.