Evaluation of Germinal Center-like Structures and B Cell Clonality in Patients with Primary Sjögren Syndrome with and without Lymphoma

Salivary gland biopsy as a prognostic tool in Sjögren's syndrome

INTRODUCTION

Primary Sjögren's syndrome (pSS) is an autoimmune disorder primarily affecting salivary and lacrimal glands, although about 40% of patients experience systemic complications. In this setting, the identification of patient phenotypes characterized by increased risk of extra-glandular involvement still represents an unmet need.

AREAS COVERED

The aim of this paper is to review the scientific evidence on the utility of salivary gland biopsies in pSS, emphasizing their role in defining prognosis. In latest years, research focused on disease-specific clinical, serological, or histological features able to categorize patient prognosis. Among histopathological features, focus score and ectopic germinal centers exhibit associations with glandular and extraglandular manifestations, including higher rates of lymphomagenesis.

EXPERT OPINION

Pathological characterization of salivary glands provides information that go beyond a mere diagnostic or classification utility, providing insights for a stratification of disease severity and for predicting systemic manifestations. Thus, a salivary gland biopsy should be offered to all patients and included in routine practice, even when not strictly required for diagnostic purposes. More advanced analysis techniques of the tissue, including immunohistochemistry and 'omics' should be further explored in longitudinal studies to boost the ability to further stratify and predict disease evolution.

Molecular B-cell clonality assay in minor salivary glands as a useful tool for the lymphoma risk assessment in Sjögren's syndrome

OBJECTIVES

Non-Hodgkin's lymphoma (NHL) risk assessment is crucial in Sjögren's syndrome (SS). We studied the prevalence of clonal immunoglobulin gene rearrangements in minor salivary glands (MSG) and their correlations with lymphoma occurrence and with previously established NHL predictors.

METHODS

Molecular B-cell expansion was studied in fresh-frozen MSG of 207 patients with either suspected SS or with suspected lymphoma during SS, using a standardised multiplex PCR assay combined with heteroduplex analysis by microcapillary electrophoresis. The assignation of clonal cases was based on EuroClonality consortium guidelines.

RESULTS

Among 207 studied patients, 31 (15%) had MSG monoclonal B-cell infiltration. Monoclonality was significantly more frequent in patients with SS (28/123, 22.8%) compared with patients without SS (3/84, 3.6%, P<0.001). Monoclonal B-cell infiltration in MSG of SS patients correlated significantly with ongoing salivary gland NHL, salivary gland swelling, CD4+ T-cell lymphopenia, rheumatoid factor (RF) activity, low complement levels and type 2 mixed cryoglobulinemia. The accumulation of biological risk factors was associated with a higher rate of MSG B-cell monoclonality given that patients with only positive RF had no probability of MSG B-cell monoclonality, RF-positive patients with 1 or 2 other risk factors had a 25.0% and 85.7% probability of MSG B-cell monoclonality, respectively.

CONCLUSION

The detection of MSG monoclonal B-cell expansion by this easy-to-perform molecular assay is useful, both at the time of diagnosis and during the course of SS. Monoclonal B-cell expansion is associated with a subset of SS patients presenting either ongoing lymphoma or other established lymphoma predictive factors.

Is minor salivary gland biopsy still mandatory in Sjogren's syndrome? Does seronegative Sjogren's syndrome exist?

Sjӧgren's disease (SjD) is a systemic autoimmune disorder characterized by the chronic inflammation and dysfunction of exocrine glands, mainly salivary glands, causing dryness of the eyes and of the mouth. The disease may affect different organs and tissues with complex and heterogeneous clinical presentation, usually with sicca symptoms, profound fatigue, chronic pain, major organ involvement, and lymphomas. SjD diagnosis is based on the combination of clinical, serological, and functional tests with histological biomarkers. Minor salivary gland biopsy (mSGB) represents the cornerstone for the diagnosis of SjD, allowing the study of the characteristic focal infiltration of B- and T lymphocytes. Besides, mSGB might also have a prognostic role, being the infiltrates more complex in patients with severe SjD. But biopsy, so far, is not mandatory for SjD and mSG ultrasound and peripheral biomarkers might replace its role in the future. Another important aspect of SjD is the presence of autoantibodies, although 20 to 30% of patients are "seronegative" for specific autoantibodies (ANA, antiRo/SSA, antiLa/SSB). The characteristics of this subset of patients are currently under evaluation and "new" autoantibodies and biomarkers might be necessary for better patient's stratification and follow-up.

EuroClonality-NGS Recommendations for Evaluation of B-Cell Clonality Analysis by Next-Generation Sequencing: A Structured Approach with the DEPART Algorithm

Next-generation sequencing (NGS)-based clonality analysis allows in-depth assessment of the clonal composition of a sample with high sensitivity for detecting small clones. Within the EuroClonality-NGS Working Group, a protocol for NGS Ig clonality analysis was developed and validated previously. This NGS-based approach was designed to generate small amplicons, making it suitable for samples with suboptimal DNA quality, especially material derived from formalin-fixed, paraffin-embedded tissue. Using expert assessment of NGS Ig clonality results as a reference, a structured algorithmic approach to the assessment of NGS-amplicon-based B-cell clonality analysis was developed. A structured approach with the Detection of clonality through Evaluation of sample quality and assessment of Pattern, Abundance and RaTio (DEPART) algorithm was proposed, which consecutively evaluates sample quality, the pattern of the clonotypes present, the abundance of the most dominant clonotypes, and the ratio between the dominant clonotypes and the background to evaluate the different Ig gene targets. Specific issues with respect to evaluation of the various Ig targets as well as the integration of results of individual targets into a molecular clonality conclusion are discussed and illustrated with case examples. Finally, the importance of interpretation of NGS-based clonality results in clinical and histopathologic contexts is discussed. It is expected that these recommendations will have clinical utility to facilitate proper evaluation of clonality assessment.

Read the clonotype: Next-generation sequencing-based lymphocyte clonality analysis and perspectives for application in pathology

Clonality assessment using the unique rearrangements of immunoglobulin (IG) and T-cell receptor (TR) genes in lymphocytes is a widely applied supplementary test for the diagnosis of B-cell and T-cell lymphoma. To enable a more sensitive detection and a more precise comparison of clones compared with conventional clonality analysis based on fragment analysis, the EuroClonality NGS Working Group developed and validated a next-generation sequencing (NGS)-based clonality assay for detection of the IG heavy and kappa light chain and TR gene rearrangements for formalin-fixed and paraffin-embedded tissues. We outline the features and advantages of NGS-based clonality detection and discuss potential applications for NGS-based clonality testing in pathology, including site specific lymphoproliferations, immunodeficiency and autoimmune disease and primary and relapsed lymphomas. Also, we briefly discuss the role of T-cell repertoire of reactive lymphocytic infiltrations in solid tumors and B-lymphoma.

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.

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.

Cellular and molecular diversity in Sjogren's syndrome salivary glands: Towards a better definition of disease subsets

Primary Sjögren's syndrome (pSS) is a highly heterogeneous disease in terms of clinical presentation ranging from a mild disease localised to the salivary and lacrimal glands, to multiorgan complications of various degrees of severity, finishing with the evolution, in around 5% of pSS patients, to B cell lymphomas most commonly arising in the inflamed salivary glands. Currently, there are poor positive or negative predictors of disease evolution able to guide patient management and treatment at early stages of the diseases. Recent understanding of the pathogenic mechanisms driving immunopathology in pSS, particularly through histological and transcriptomic analysis of minor and parotid salivary gland (SG) biopsies, has highlighted a high degree of cellular and molecular heterogeneity of the inflammatory lesions but also allowed the identification of clusters of patients with similar underlying SG immunopathology. In particular, patients presenting with high degrees of B/T cell infiltration and the formation of ectopic lymphoid structures (ELS) in the SG have been associated, albeit with conflicting results, with higher degree of disease severity and enhanced risk of lymphoma evolution, suggesting that a dysregulated adaptive immune response plays a key role in driving disease manifestations in pSS. Recent data from randomised clinical trials with novel biological therapies in pSS have also highlighted the potential role of SG immunopathology and molecular pathology in stratifying patients for trial inclusion as well as assessing proof of mechanisms in longitudinal SG biopsies before and after treatment. Although significant progress has been made in the understanding of disease pathogenesis and heterogeneity through cellular and molecular SG pathology, further work is needed to validate their clinical utility in routine clinical settings and in randomised clinical trials.

Focal lymphocytic sialadenitis and ectopic germinal centers in oral reactive lesions and primary Sjögren's syndrome: a comparative study

Focal lymphocytic sialadenitis (FLS), an important diagnostic criterion for Sjögren's syndrome (SS) diagnosis, can also be observed when assessing minor salivary gland (mSG) biopsies from healthy asymptomatic individuals (non-SS patients). Fifty cases of primary SS (pSS group) and 31 cases of oral reactive lesions (non-SS non-sicca group) containing also typical FLS features, were assessed by morphological and immunohistochemical (CD10, CD23 and Bcl-6) analysis, aiming at the detection of GCs. All pSS cases showed FLS with focus score (FS) ≥ 1. In the non-SS non-sicca group, 12, 10 and 9 cases showed FLS with FS ≥ 1, FLS with FS < 1 and FLS associated with chronic sclerosing sialadenitis with FS < 1, respectively. The morphological analysis revealed similar frequency of GCs in pSS (20%) and non-SS non-sicca group (19%). The area (p = 0.052) and largest diameter (p = 0.245) of GCs were higher in pSS than non-SS non-sicca group. The FS and number of foci were significantly higher in pSS than non-SS non-sicca group with FS < 1. Immunohistochemistry confirmed all morphological findings (GCs showing CD23 and Bcl-6 positivity, with variable CD10 expression) and additionally in 3 and 1 cases of the pSS and non-SS non-sicca group, respectively. Moreover, another 6 and 2 cases of the pSS and non-SS non-sicca group with FS ≥ 1, respectively, showed positivity only for CD23. FLS can also be observed when assessing oral reactive lesions, which showed similar frequency of GCs with those found in pSS patients. Further studies, including functional analysis of lymphocytic populations and GCs in FLS, are encouraged.

Inflammatory Stratification in Primary Sjögren's Syndrome Reveals Novel Immune Cell Alterations in Patients' Minor Salivary Glands

There is a critical need to deconvolute the heterogeneity displayed by the minor salivary glands of primary Sjögren’s syndrome (pSS) patients. This is challenging primarily because the disease etiology remains unknown. The hypothesis includes that initial events in the disease pathogenesis target the salivary glands, thereby triggering the development of focal infiltrates (≥50 mononuclear cells) and finally germinal center-like structures. However, the proportion of key mononuclear immune cells residing at these sites, in combination with the overall ratio of morphometric tissue atrophy and adipose infiltration within the minor salivary glands (MSG) parenchyma at distinct phases of inflammatory disease establishment and progression have not been quantified in detail. In this cross-sectional study, we intended to address this problem by stratifying 85 patients into mild (S1), moderate (S2), and severe (S3) stages using the Inflammatory severity index. We found that mild (<3%) and marked (≥3%) levels of atrophy were accompanied by the respective levels of adipose infiltration in the non-SS sicca controls (p <0.01), but not in pSS patients. The percentage of adipose infiltration significantly correlated with the age of patients (r = 0.458, p <0.0001) and controls (r = 0.515, p <0.0001). The CD4⁺ T helper cell incidence was reduced in the focal infiltrates of the MSG of S2 patients compared to S1 (p <0.01), and in S2 compared to S1 and S3 combined (p <0.05). CD20⁺ B cells increased from S1 to S3 (p <0.01) and S2 to S3 (p <0.01), meanwhile CD138⁺ plasma cells diminished in S3 patients compared to both S1 and S2 groups combined (p <0.01). The proportion of patients with anti-Ro/SSA⁺, anti-La/SSB⁺, and RF⁺ increased over the course of inflammatory disease progression and they were significantly more common in the S3 group relative to S1 (p <0.05). On the other hand, S2 patients measured a higher mean salivary flow relative to S1 and S3 patients combined (p <0.05). Our results demonstrate how the proposed Inflammatory severity index stratification revealed pathological cell and tissue-associated aberrations in the salivary component over the course of inflammatory progression, and their correlations to clinical outcomes. This could be directly transferred to the optimization of available diagnostic strategies applied for pSS patients.

Pathogenetic Mechanisms Implicated in Sjögren's Syndrome Lymphomagenesis: A Review of the Literature

Sjögren's Syndrome (SS) is a chronic autoimmune disorder characterized by focal mononuclear cell infiltrates that surround the ducts of the exocrine glands, impairing the function of their secretory units. Compared to other autoimmune disorders, SS is associated with a notably high incidence of non-Hodgkin lymphoma (NHL) and more frequently mucosa associated lymphoid tissue (MALT) lymphoma, leading to increased morbidity and mortality rates. High risk features of lymphoma development include systemic extraepithelial manifestations, low serum levels of complement component C4 and mixed type II cryoglobulinemia. The discrimination between reactive and neoplastic lymphoepithelial lesion (LEL) is challenging, probably reflecting a continuum in the evolution from purely inflammatory lymphoid infiltration to the clonal neoplastic evolution. Early lesions display a predominance of activated T cells, while B cells prevail in severe histologic lesions. This strong B cell infiltration is not only a morphologic phenomenon, but it is also progressively associated with the presence of ectopic germinal centers (GCs). Ectopic formation of GCs in SS represents a complex process regulated by an array of cytokines, adhesion molecules and chemokines. Chronic antigenic stimulation is the major driver of specific B cell proliferation and increases the frequency of their transformation in the ectopic GCs and marginal zone (MZ) equivalents. B cells expressing cell surface rheumatoid factor (RF) are frequently detected in the salivary glands, suggesting that clonal expansion might arise from antigen selection of RF-expressing B cells. Abnormal stimulation and incomplete control mechanisms within ectopic lymphoid structures predispose RF MZ like cells to lymphoma development. Immunoglobulin recombination, somatic mutation and isotype switching during B cell development are events that may increase the translocation of oncogenes to immunoglobulin loci or tumor suppressor gene inactivation, leading to monoclonal B cell proliferation and lymphoma development. Concerning chronic antigenic stimulation, conclusive data is so far lacking. However immune complexes containing DNA or RNA are the most likely candidates. Whether additional molecular oncogenic events contribute to the malignant overgrowth remains to be proved.

Expression of BAFF and BAFF receptors in primary Sjögren's syndrome patients with ectopic germinal center-like structures

B cell-activating factor (BAFF) is an essential cytokine in primary Sjögren's syndrome (pSS) physiopathology. It has been reported that pSS patients develop germinal center-like (GC-like) structures in their minor salivary glands (MSGs). BAFF, BAFF-R, TACI, and BCMA expression was analyzed in MSGs from 29 subjects (nonspecific chronic sialadenitis and focal lymphocytic sialadenitis with the presence [pSS-GC(+)] or absence [pSS-GC(-)] of GC-like structures). Twenty-four percent of patients showed ectopic GC-like structures and a high focus score [p < 0.001 vs pSS-GC(-)]. BAFF serum levels (sBAFF) were high in pSS patients (p = 0.025 vs healthy subjects). However, the pSS-GC(-) group showed higher sBAFF levels than pSS-GC(+) patients. BAFF and BAFF-R glandular expression levels were higher in pSS-GC(+) patients, without significant differences compared to pSS-GC(-) patients. Soluble levels of BAFF correlated with anti-La/SSB antibodies and disease duration. Our results showed that BAFF could contribute to focal lymphocytic infiltration. The role of BAFF-binding receptors in MSGs is proposed as a mechanism for the possible establishment of ectopic GC-like structures and disease progression in some patients. In conclusion, this study supports previous evidence that considers the active BAFF system role in the pathogenesis of pSS and the need for strong biomarkers in this disease.

World Workshop on Oral Medicine VII: Biomarkers predicting lymphoma in the salivary glands of patients with Sjögren's syndrome-A systematic review

OBJECTIVE

To conduct a systematic review of studies exploring potential biomarkers for development, course, and efficacy of treatment of lymphomas in salivary glands of patients with Sjögren's syndrome.

MATERIAL AND METHODS

Eligible studies were identified through a comprehensive search of two databases, that is, PubMed and EMBASE. Quality of included articles was assessed with the "Quality In Prognosis Studies" (QUIPS) tool. The "CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies" (CHARMS) was used to facilitate data extraction.

RESULTS

Fifty-eight studies met the inclusion criteria. Only one study assessed the progression of lymphoma. Moderate risk of bias was detected in "outcome measurement," "study participation," and "study confounding" domains. Parotid gland enlargement, mixed monoclonal cryoglobulins, and low C4 levels represented strongest predictors of lymphoma development. The role of histological biomarkers, and specifically germinal centers, remains controversial. Clinical and methodological heterogeneity across studies precluded conduct of a meta-analysis.

CONCLUSIONS

Specific biomarkers in combination with clinical manifestations represent potential candidates for advancing precision medicine approaches to lymphoma prediction in patients with Sjögren's syndrome. Current focus has increasingly been on genetic and epigenetic markers as candidate predictors. Predictive accuracy of key biomarker candidates remains to be tested in well-designed prospectively followed Sjögren's syndrome cohorts.

Predictive markers of lymphomagenesis in Sjögren's syndrome: From clinical data to molecular stratification

Sjögren's syndrome (SS) is a chronic systemic autoimmune disease, affecting predominantly the exocrine glands, a large array of systemic manifestations and high risk of lymphoma development. The latter constitutes the major adverse outcome of SS contributing in the increased morbidity and mortality of the disease. The vast majority of lymphomas in SS are B-cell non-Hodgkin's lymphomas (NHL), primarily indolent mucosa-associated lymphoid tissue (MALT) lymphomas, followed by nodal marginal zone lymphomas (NMZL) and diffuse large B cell lymphomas (DLBCL). In the last 3 decades and due to the adverse impact of NHL in disease outcome, an effort has been undertaken to identify markers and models predicting patients with SS at high risk for lymphoma development. Several epidemiological, clinical, laboratory and histological parameters, some of which are evident at the time of SS diagnosis, were proved to independently predict the development of NHL. These include salivary gland enlargement, skin vasculitis/purpura, glomerulonephritis, peripheral neuropathy, Raynaud's phenomenon, lymphadenopathy, splenomegaly, cytopenias, hypocomplementemia, cryoglobulinemia, rheumatoid factor, anti-Ro/La autoantibodies, hypergammaglobulinemia, serum monoclonal gammopathy, biopsy focus score and organization of lymphocytic infiltrates in the salivary glands into ectopic germinal centers. Prediction models combining some of the afore-mentioned predictors have also been described. However, the identification of specific and sensitive molecular biomarkers, related to the process of lymphomagenesis is still pending. Recently, we described a novel biomarker the miR200b-5p micro-RNA. Low levels of this miRNA in the minor salivary glands, appears to discriminate with high specificity and sensitivity the SS patients who have from those who do not have NHL. miR200b-5p, being expressed years before the clinical onset of NHL, independently predicts NHL development with a predictive value higher than the previously published multifactorial models and has a possible role in the monitoring of therapeutic response. Thus, it is a strong candidate for the identification and follow-up of patients at risk.

Prognostic markers of lymphoma development in primary Sjögren syndrome

Sjögren syndrome is a systemic autoimmune disease that principally affects women between the fourth and sixth decades of life who present with sicca symptomatology caused by dryness of the main mucosal surfaces. The clinical spectrum of Sjögren syndrome extends from dryness to systemic involvement. Since 1978, Sjögren syndrome has been closely associated with an enhanced risk of lymphoma, one of the most severe complications a patient may develop. Primary Sjögren syndrome patients have a 10-44-fold greater risk of lymphoma than healthy individuals, higher than that reported for systemic lupus erythematosus and rheumatoid arthritis. The close link between lymphoma and Sjögren syndrome is clearly exemplified by the very specific type of lymphoma arising in Sjögren syndrome patients, mainly low-grade B-cell lymphomas (predominantly a marginal zone histological type) with primary extranodal involvement of the major salivary glands (overwhelmingly parotid), with a primordial role of cryoglobulinemic-related markers (both clinical and immunological). The most recent studies support a higher number of risk factors detected in an individual leads to a higher lymphoma risk. A close follow-up of high-risk groups with longitudinal assessments of all known risk factors, including cryoglobulin-related markers and EULAR Sjögren's syndrome disease activity index measurement in particular, is mandatory.

[Sjögren's syndrome update: Clinical and therapeutic aspects]

Sjögren's syndrome (SS) is a systemic orphan disease. It is characterized by the involvement of epithelial tissues leading to the term of autoimmune epithelitis. New classification criteria have been developed in 2016. New scores have also been developed: a patient-reported outcome called ESSPRI and a score assessing systemic activity of the disease called ESSDAI. These new tools are very helpful to better stratify patients and to customize the management of this very heterogeneous disease. Among the autoimmune diseases, SS is associated with the highest risk of lymphoma. Five to ten percent of the patients will have a B cell lymphoma mostly a low-grade lymphoma developing from mucosa-associated lymphoid tissue (MALT). Major advances have been made in this field: pathogeny is better understood, new predictors are available and progresses have been made in the management of this severe complication. Research in the field of SS is very dynamic as illustrated by the high number of therapeutic trials. There is hope that these innovations, reviewed in the present article, will have potential significant repercussions for the patients in the next few years.

Lymphomas complicating primary Sjögren's syndrome: from autoimmunity to lymphoma

Lymphoma development is the most serious complication of SS and the main factor impacting on mortality rate in patients with this condition. Lymphomas in SS are most commonly extranodal non-Hodgkin B-cell lymphomas of the mucosa-associated lymphoid tissue and frequently arise in salivary glands that are the target of a chronic inflammatory autoimmune process. Extensive work on lymphomagenesis in SS has established that the progression towards B-cell lymphoma is a multistep process related to local chronic antigenic stimulation of B cells. These neoplastic B cells in SS frequently derived from autoreactive clones, most commonly RF-producing B cells, which undergo uncontrolled proliferation and malignant escape. In this review, we highlight the most important recent findings that have enhanced our understanding of lymphoma development in SS, with particular reference to the close link between autoimmunity and lymphomagenesis. We also discuss how the identification of key factors involved in B-cell malignancies may impact on our ability to identify at early stages patients at increased risk of lymphoma with potential significant repercussions for the clinical management of SS patients. Finally, we identified the most promising areas of current and further research with the potential to provide novel basic and translational discoveries in the field. The questions of finding new biomarkers, developing a validated score for predicting lymphoma occurrence and assessing if a better control of disease activity will decrease the risk of lymphoma in primary SS will be the enthralling questions of the next few years.

Severe headache in primary Sjögren's syndrome treated with intrathecal rituximab

A severe and persistent migrainous headache in a patient with primary Sjøgren's syndrome unresponsive to treatment with immunosuppressive drugs, triptans, opioids, and NSAIDs, responded successfully to intrathecal B-cell depletion with rituximab. We hypothesize that brain-resident autoreactive B cells were involved in headache pathogenesis and were eliminated by this procedure.

Current views on the pathogenesis of Sjögren's syndrome

PURPOSE OF REVIEW

The purpose of this review is to provide an insight into the pathophysiological mechanisms involved in the pathogenesis of primary Sjögren's Syndrome (pSS), highlighting recent findings with potential therapeutic repercussions.

RECENT FINDINGS

In the last 2 years, epigenetic analyses provided new insights into pSS pathogenesis. Characterization of DNA methylation patterns, chromatin structures and microRNA confirmed the importance of aberrant interferon and B-cell responses in the development of the disease. The formation of ectopic B-cell follicles with germinal centers is now a well recognized pathogenic mechanism within salivary glands of pSS. In the context of ectopic germinal centers reaction, T/B-cell interactions, that is regarding T-helper 17 and T-follicular helper cells, and their respective counterparts, T-regulatory and T-follicular regulatory cells, appear particularly relevant in pSS pathogenesis as their imbalance is associated with a dysregulation of B-cell dynamics and the production of autoantibodies.

SUMMARY

Advances in the understanding of pSS pathogenesis have paved the way for clinical trials with novel biologic agents targeting immune pathways regulating T/B-cell interactions and downstream B-cell activation. Reverse translation from these studies provides invaluable novel information of the mechanisms sustaining autoimmunity and chronic inflammation in pSS.

Lymphomagenesis in Sjögren's syndrome: Predictive biomarkers towards precision medicine

Sjögren's syndrome (SS) is characterized by B cell hyperactivity documented by the production of plethora of autoantibodies and a strong tendency for NHL of B cell origin. Classical predictors of lymphoma have been already proposed and proved their validity, including clinical, serological and histopathologic biomarkers. The process of lymphomagenesis is multistep and encompasses mechanisms of antigen driven selection of the BCR with RF activity and various genetic contributors implicated in B cell proliferation, cell growth and cell cycle control, enhanced by a complex milieu of cytokines and trophic agents that are abundant within the inflammatory lesion of minor salivary glands of SS patients. Extensive efforts in the basic research field have revealed several novel biomarkers for lymphoma prediction while the major cellular and molecular mechanisms of evolutionary transition of B cells towards malignancy are under investigation. In this review, we present the current data regarding the newly proposed biomarkers for SS associated lymphoma prediction and a hypothetical model of lymphomagenesis based on the emerging data.

Morphological alterations in minor salivary glands of HTLV1+ patients: A pilot study

BACKGROUND

Among the complex of HTLV-associated diseases, Sjögren's syndrome (SS) is one of the most controversial. This work aims to detect morphological and inflammatory alterations, including clues of the presence of HTLV-1, in minor salivary glands of patients with dryness symptoms.

METHODS

We have assessed HTLV-1-seropositive patients (HTLV-1 group) and patients with SS (SS group). We used formalin-fixed, paraffin-embedded minor salivary gland tissue to evaluate the morphological aspects and, by means of immunohistochemistry, the presence of Tax protein, CD4, CD8 and CD20 cells. Additionally, viral particles and proviral load were analysed by PCR.

RESULTS

The HTLV-1 group had the highest prevalence of non-specific chronic sialadenitis (85.71%; P = 0.017) and greater amount of T CD8⁺ cells. In the SS group, focal lymphocytic sialadenitis (80%; P = 0.017) prevailed, with a greater amount of B CD20⁺ . Both immunohistochemistry and PCR identified the Tax protein and its gene in the salivary glands of both groups and in similar proportions.

CONCLUSION

The results indicate that HTLV-1-seropositive patients have different patterns of morphological/inflammatory alterations, suggesting a likely difference in the process of immune activation.

Ectopic Germinal Center-Like Structures in Minor Salivary Gland Biopsy Tissue Predict Lymphoma Occurrence in Patients With Primary Sjögren's Syndrome

OBJECTIVE

To determine risk factors for primary Sjögren's syndrome (SS)-associated lymphoma in a multicenter cohort of patients, with analysis of the predictive power of previously reported risk factors, including the presence of ectopic germinal center (GC)-like structures in minor salivary gland (MSG) biopsy tissue.

METHODS

One hundred fifteen patients with primary SS were included, and MSG biopsy tissue from these patients was retrospectively examined, focusing on the presence of ectopic GC-like structures. Epidemiologic, clinical, biologic, immunologic, and histologic data were collected at the time of diagnosis of primary SS. Patients with non-Hodgkin's lymphoma (NHL) were compared with those without NHL during the follow-up period, using a Cox proportional hazards multiple regression model.

RESULTS

NHL was diagnosed in 8 patients (6.96%), and ectopic GC-like structures in 19 patients (16.5%). The presence of ectopic GC-like structures was associated with a 7.8-fold increased risk of lymphoma occurrence (95% confidence interval [95% CI] 1.73-34.86 [P = 0.0075]). Other independent predictors included a positive cryoglobulin test result (hazard ratio [HR] 7.10, 95% CI 1.74-28.92 [P = 0.006]), male sex (HR 28.73, 95% CI 4.46-144.87 [P = 0.0004]), sensorimotor neuropathy (HR 35.48, 95% CI 5.79-217.39 [P = 0.0001]), and splenomegaly (HR 19.9, 95% CI 4.4-90 [P = 0.0001]).

CONCLUSION

The presence of ectopic GC-like structures in MSG biopsy tissue is associated with the risk of lymphoma in patients with primary SS. These data reinforce the major role of MSG biopsy tissue in primary SS, for the identification a priori of a subgroup of patients with the highest risk of lymphoma.

Russell body gastritis with Dutcher bodies evaluated using magnification endoscopy

Russell body gastritis (RBG) is an unusual type of chronic gastritis characterized by marked infiltration of Mott cells, which are plasma cells filled with spherical eosinophilic bodies referred to as Russell bodies. It was initially thought that Helicobacter pylori (H. pylori) infection was a major cause of RBG and that the infiltrating Mott cells were polyphenotypic; however, a number of cases of RBG without H. pylori infection or with monoclonal Mott cells have been reported. Thus, diagnostic difficulty exists in distinguishing RBG with monoclonal Mott cells from malignant lymphoma. Here, we report an unusual case of an 86-year-old-Japanese man with H. pylori-positive RBG. During the examination of melena, endoscopic evaluation confirmed a 13-mm whitish, flat lesion in the gastric antrum. Magnification endoscopy with narrow-band imaging suggested that the lesion was most likely a poorly differentiated adenocarcinoma. Biopsy findings were consistent with chronic gastritis with many Mott cells with intranuclear inclusions referred to as Dutcher bodies. Endoscopic submucosal dissection confirmed the diagnosis of RBG with kappa-restricted monoclonal Mott cells. Malignant lymphoma was unlikely given the paucity of cytological atypia and Ki-67 immunoreactivity of monoclonal Mott cells. This is the first reported case of RBG with endoscopic diagnosis of malignant tumor and the presence of Dutcher bodies.

Standardisation of labial salivary gland histopathology in clinical trials in primary Sjögren's syndrome

Labial salivary gland (LSG) biopsy is used in the classification of primary Sjögren's syndrome (PSS) and in patient stratification in clinical trials. It may also function as a biomarker. The acquisition of tissue and histological interpretation is variable and needs to be standardised for use in clinical trials. A modified European League Against Rheumatism consensus guideline development strategy was used. The steering committee of the ad hoc working group identified key outstanding points of variability in LSG acquisition and analysis. A 2-day workshop was held to develop consensus where possible and identify points where further discussion/data was needed. These points were reviewed by a subgroup of experts on PSS histopathology and then circulated via an online survey to 50 stakeholder experts consisting of rheumatologists, histopathologists and oral medicine specialists, to assess level of agreement (0-10 scale) and comments. Criteria for agreement were a mean score ≥6/10 and 75% of respondents scoring ≥6/10. Thirty-nine (78%) experts responded and 16 points met criteria for agreement. These points are focused on tissue requirements, identification of the characteristic focal lymphocytic sialadenitis, calculation of the focus score, identification of germinal centres, assessment of the area of leucocyte infiltration, reporting standards and use of prestudy samples for clinical trials. We provide standardised consensus guidance for the use of labial salivary gland histopathology in the classification of PSS and in clinical trials and identify areas where further research is required to achieve evidence-based consensus.

Low Protein A20 in Minor Salivary Glands is Associated with Lymphoma in Primary Sjögren's Syndrome

Patients with primary Sjögren's syndrome (pSS) have an increased risk of developing lymphomas, particularly the subtype mucosa-associated lymphoid tissue (MALT) lymphoma. Chronic antigen stimulation and increased activation of nuclear factor-κB (NF-κB) are important factors for the pathogenesis of MALT lymphomas. Protein A20 is an inhibitor of NF-κB. A recent study of pSS-associated MALT lymphomas identified potential functional abnormalities in the TNFAIP3 gene, which encodes protein A20. The present study aimed to assess protein A20 by immunohistochemistry (IHC) in minor salivary glands (MSGs) and lymphoma tissue sections of patients with pSS and investigate a potential association with lymphoma development. Protein A20 staining in lymphocytes was scored in four categories (0 = negative, 1 = weak, 2 = moderate and 3 = strong). For statistical purposes, these scores were simplified into negative (scores 0-1) and positive (scores 2-3). We investigated associations between protein A20-staining, focus scores, germinal centre (GC)-like structures and monoclonal B-cell infiltration in MSGs. MSG protein A20 staining was weaker in pSS patients with lymphomas than in those without lymphomas (P = 0.01). Weak protein A20 staining was also highly associated with a lack of GC formation (P < 0.01). Finally, weaker A20 staining was observed in the majority of pSS-associated MALT lymphoma tissues. In conclusion, we found absent or weak protein A20 immunoreactivity in MSGs of patients with pSS with lymphomas. This finding indicates that protein A20 downregulation in lymphocytes might be a mechanism underlying lymphoma genesis in patients with pSS.

Sjögren syndrome

Sjögren syndrome (SjS) is a systemic autoimmune disease that primarily affects the exocrine glands (mainly the salivary and lacrimal glands) and results in the severe dryness of mucosal surfaces, principally in the mouth and eyes. This disease predominantly affects middle-aged women, but can also be observed in children, men and the elderly. The clinical presentation of SjS is heterogeneous and can vary from sicca symptoms to systemic disease (characterized by peri-epithelial lymphocytic infiltration of the affected tissue or the deposition of the immune complex) and lymphoma. The mechanism underlying the development of SjS is the destruction of the epithelium of the exocrine glands, as a consequence of abnormal B cell and T cell responses to the autoantigens Ro/SSA and La/SSB, among others. Diagnostic criteria for SjS include the detection of autoantibodies in patient serum and histological analysis of biopsied salivary gland tissue. Therapeutic approaches for SjS include both topical and systemic treatments to manage the sicca and systemic symptoms of disease. SjS is a serious disease with excess mortality, mainly related to the systemic involvement of disease and the development of lymphomas in some patients. Knowledge of SjS has progressed substantially, but this disease is still characterized by sicca symptoms, the systemic involvement of disease, lymphocytic infiltration to exocrine glands, the presence of anti-Ro/SSA and anti-La/SSB autoantibodies and the increased risk of lymphoma in patients with SjS.

Salivary Gland Pathology in Sjögren's Syndrome

Primary Sjögren syndrome (pSS) can be considered a systemic autoimmune disease with a strong organ bias. The involvement of the exocrine glands is prevalent and drives the pathognomonic manifestations of dryness that define the sicca syndrome. The salivary glands also represent the hub of pSS pathology. Elements belonging to both innate and acquired immune responses have been described at this site that contribute to disease establishment and progression. The interaction between those elements and their relative contributions to the clinical manifestations and lymphoma progression largely remain to be addressed.

Parotid Gland Biopsy, the Alternative Way to Diagnose Sjögren Syndrome

Salivary gland biopsy is a technique broadly applied for the diagnosis of Sjögren syndrome (SS), lymphoma in SS, and connective tissue disorders (sarcoidosis, amyloidosis). In SS characteristic histology findings are found, including lymphocytic infiltration surrounding the excretory ducts in combination with destruction of acinar tissue. In this article the main techniques are described for taking labial and parotid salivary gland biopsies with respect to their advantages, postoperative complications, and usefulness for diagnostic procedures, monitoring disease progression, and evaluation of treatment.