Characterization of prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome

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.

Predicting lymphoma in Sjögren's syndrome and the pathogenetic role of parotid microenvironment through precise parotid swelling recording

OBJECTIVE

Parotid swelling (PSW) is a major predictor of non-Hodgkin lymphoma (NHL) in primary Sjögren's syndrome (pSS). However, since detailed information on the time of onset and duration of PSW is scarce, this was investigated to verify whether it may lead to further improved prediction. NHL localisation was concomitantly studied to evaluate the role of the parotid gland microenvironment in pSS-related lymphomagenesis.

METHODS

A multicentre study was conducted among patients with pSS who developed B cell NHL during follow-up and matched controls that did not develop NHL. The study focused on the history of salivary gland and lachrymal gland swelling, evaluated in detail at different times and for different durations, and on the localisation of NHL at onset.

RESULTS

PSW was significantly more frequent among the cases: at the time of first referred pSS symptoms before diagnosis, at diagnosis, and from pSS diagnosis to NHL. The duration of PSW was evaluated starting from pSS diagnosis, and the NHL risk increased from PSW of 2-12 months to > 12 months. NHL was prevalently localised in the parotid glands of the cases.

CONCLUSION

A more precise clinical recording of PSW can improve lymphoma prediction in pSS. PSW as a very early symptom is a predictor, and a longer duration of PSW is associated with a higher risk of NHL. Since lymphoma usually localises in the parotid glands, and not in the other salivary or lachrymal glands, the parotid microenvironment appears to be involved in the whole history of pSS and related lymphomagenesis.

Safety, patient acceptance and diagnostic accuracy of ultrasound core needle biopsy of parotid or submandibular glands in primary Sjögren's syndrome with suspected salivary gland lymphoma

Background

Enlargement of the major salivary glands (SGs) is a major risk factor for B-cell lymphoma among patients with primary Sjögren’s syndrome (pSS). Ultrasound-guided core needle biopsy (US-guided CNB) could be a novel technique to manage SG enlargement among patients with pSS.

Objective

Accordingly, this study’s main aim was to evaluate the safety, patient tolerance and diagnostic accuracy of US-guided CNB procedure for patients with pSS with major SG enlargement.

Methods

Patients with clinical diagnosis of pSS and a clinical indication for SG biopsy consecutively underwent US-guided CNB between September 2019 and June 2021. These patients were evaluated clinically 1, 2 and 12 weeks after US-guided CNB. Patients were asked to complete a questionnaire about postprocedural complications as well as periprocedural pain, using the Visual Analogue Scale. Complications were categorised as transient (<12 weeks) or persistent (≥12 weeks).

Results

US-guided CNB was performed on 30 major salivary glands (22 parotid glands and 8 submandibular glands). The procedure was well tolerated. Transient complications—such as haematoma, swelling—were observed among 43% of patients, and mean periprocedural pain was low. However, no persistent complications were reported during the study’s follow-up period.

Conclusion

US-guided CNB represents a novel approach for the management of patients with pSS with SG enlargement. The procedure showed remarkable patient safety and tolerance, allowing adequate glandular sampling and a definite diagnosis for almost all participating patients without long-term complications.

Diagnosis and management of lung involvement in systemic lupus erythematosus and Sjögren's syndrome: a literature review

Lung involvement in systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS) has extensively been outlined with a multiplicity of different manifestations. In SLE, the most frequent finding is pleural effusion, while in pSS, airway disease and parenchymal disorders prevail. In both cases, there is an increased risk of pre-capillary and post-capillary pulmonary arterial hypertension (PAH) and pulmonary venous thromboembolism (VTE). The risk of VTE is in part due to an increased thrombophilic status secondary to systemic inflammation or to the well-established association with antiphospholipid antibody syndrome (APS). The lung can also be the site of an organ-specific complication due to the aberrant pathologic immune-hyperactivation as occurs in the development of lymphoma or amyloidosis in pSS. Respiratory infections are a major issue to be addressed when approaching the differential diagnosis, and their exclusion is required to safely start an immunosuppressive therapy. Treatment strategy is mainly based on glucocorticoids (GCs) and immunosuppressants, with a variable response according to the primary pathologic process. Anticoagulation is recommended in case of VTE and multi-targeted treatment regimens including different drugs are the mainstay for PAH management. Antibiotics and respiratory physiotherapy can be considered relevant complement therapeutic measures. In this article, we reviewed lung manifestations in SLE and pSS with the aim to provide a comprehensive overview of their diagnosis and management to physicians taking care of patients with connective tissue diseases.

Shared Pathogenetic Features Between Common Variable Immunodeficiency and Sjögren's Syndrome: Clues for a Personalized Medicine

Common variable immunodeficiency disorders (CVID) are a group of rare diseases of the immune system and the most common symptomatic primary antibody deficiency in adults. The “variable” aspect of CVID refers to the approximately half of the patients who develop non-infective complications, mainly autoimmune features, in particular organ specific autoimmune diseases including thyroiditis, and cytopenias. Among these associated conditions, the incidence of lymphoma, including mucosal associated lymphoid tissue (MALT) type, is increased. Although these associated autoimmune disorders in CVID are generally attributed to Systemic Lupus Erythematosus (SLE), we propose that Sjogren’s syndrome (SS) is perhaps a better candidate for the associated disease. SS is an autoimmune disorder characterized by the lymphocytic infiltrates of lacrimal and salivary glands, leading to dryness of the eyes and mouth. Thus, it is a lymphocyte aggressive disorder, in contrast to SLE where pathology is generally attributed to auto-antibody and complement activation. Although systemic lupus erythematosus (SLE) shares these features with SS, a much higher frequency of MALT lymphoma distinguishes SS from SLE. Also, the higher frequency of germ line encoded paraproteins such as the monoclonal rheumatoid factor found in SS patients would be more consistent with the failure of B-cell VDJ switching found in CVID; and in contrast to the hypermutation that characterizes SLE autoantibodies. Thus, we suggest that SS may fit as a better “autoimmune” association with CVID. Examining the common underlying biologic mechanisms that promote lymphoid infiltration by dysregulated lymphocytes and lymphoma in CVID may provide new avenues for treatment in both the diseases. Since the diagnosis of SLE or rheumatoid arthritis is usually based on specific autoantibodies, the associated autoimmune features of CVID patients may not be recognized in the absence of autoantibodies.

Ultrasound-guided core needle biopsy compared with open biopsy: a new diagnostic approach to salivary gland enlargement in Sjögren's syndrome?

OBJECTIVE

Persistent (≥2 months) major salivary gland enlargement in primary SS (pSS) patients is a well-known sign of possible involvement by B cell lymphoma. The study aimed to evaluate the diagnostic accuracy and safety of US-guided core needle biopsy (CNB) of major salivary glands compared with open surgical biopsy.

METHODS

Prospective pSS patients (cases) with clinically persistent salivary gland enlargement underwent US-guided CNB and were compared with retrospective pSS patients (controls) submitted to open surgical biopsy. The features analysed were pre-biopsy clinical and laboratory findings, adequacy of the material for histology and diagnostic-rendered and biopsy-related complications (reported by the patient with a questionnaire and clinically verified).

RESULTS

Thirteen cases underwent US-guided CNB: in nine, biopsy was performed on the parotid gland and in four it was performed on the submandibular gland. Sufficient material was obtained for pathological diagnosis in all samples. The final diagnoses were 5 (38.5%) B cell lymphoma, 1 (7.7%) lymphoepithelial sialadenitis, 4 (30.7%) other sialadenitis (granulomatous consistent with sarcoidosis, IgG4-related disease, chronic sclerosing, diffuse chronic) and 3/13 (23.1%) miscellaneous lesions. Thirteen controls underwent open surgical biopsy of the parotid. In one, inadequate material was obtained, while in 12 (92.3%) the pathologic diagnoses were 4 (33.3%) B cell lymphoma, 2 (16.7%) lymphoepithelial sialadenitis, 4 (33.3%) uncertain lymphoproliferative lesions and 2 (16.7%) miscellaneous lesions. Six cases (46.1%) reported six transient complications and 12/13 (92.3%) controls had 2 persistent and 14 transient complications.

CONCLUSION

US-guided CNB represents a novel, clinically relevant and safe approach for the management of pSS patients with parotid or submandibular persistent enlargement.

A biomarker for lymphoma development in Sjogren's syndrome: Salivary gland focus score

The aim of this study is to explore the role of labial minor salivary gland (LMSG) focus score (FS) in stratifying Sjögren's Syndrome (SS) patients, lymphoma development prediction and to facilitate early lymphoma diagnosis. Ιn an integrated cohort of 1997 patients, 618 patients with FS ≥ 1 and at least one-year elapsing time interval from SS diagnosis to lymphoma diagnosis or last follow up were identified. Clinical, laboratory and serological features were recorded. A data driven logistic regression model was applied to identify independent lymphoma associated risk factors. Furthermore, a FS threshold maximizing the difference of time interval from SS until lymphoma diagnosis between high and low FS lymphoma subgroups was investigated, to develop a follow up strategy for early lymphoma diagnosis. Of the 618 patients, 560 were non-lymphoma SS patients while the other 58 had SS and lymphoma. FS, cryoglobulinemia and salivary gland enlargement (SGE) were proven to be independent lymphoma associated risk factors. Lymphoma patients with FS ≥ 4 had a statistically significant shorter time interval from SS to lymphoma diagnosis, compared to those with FS < 4 (4 vs 9 years, respectively, p = 0,008). SS patients with FS ≥ 4 had more frequently B cell originated manifestations and lymphoma, while in patients with FS < 4, autoimmune thyroiditis was more prevalent. In the latter group SGE was the only lymphoma independent risk factor. A second LMSG biopsy is patients with a FS ≥ 4, 4 years after SS diagnosis and in those with FS < 4 and a history of SGE, at 9-years, may contribute to an early lymphoma diagnosis. Based on our results we conclude that LMSG FS, evaluated at the time of SS diagnosis, is an independent lymphoma associated risk factor and may serve as a predictive biomarker for the early diagnosis of SS-associated lymphomas.

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.

Salivary Gland Ultrasonography in Sjögren's Syndrome: A European Multicenter Reliability Exercise for the HarmonicSS Project

Objectives: Salivary gland ultrasonography (SGUS) is increasingly applied for the management of primary Sjögren's syndrome (pSS). This study aims to: (i) compare the reliability between two SGUS scores; (ii) test the reliability among sonographers with different levels of experience.

Methods: In the reliability exercise, two four-grade semi-quantitative SGUS scoring systems, namely De Vita et al. and OMERACT, were tested. The sonographers involved in work-package 7 of the HarmonicSS project from nine countries in Europe were invited to participate. Different levels of sonographers were identified on the basis of their SGUS experience and of the knowledge of the tested scores. A dedicated atlas was used as support for SGUS scoring.

Results: Twenty sonographers participated in the two rounds of the reliability exercise. The intra-rater reliability for both scores was almost perfect, with a Light's kappa of 0.86 for the De Vita et al. score and 0.87 for the OMERACT score. The inter-rater reliability for the De Vita et al. and the OMERACT score was substantial with Light's Kappa of 0.75 and 0.77, respectively. Furthermore, no significant difference was noticed among sonographers with different levels of experience.

Conclusion: The two tested SGUS scores are reliable for the evaluation of major salivary glands in pSS, and even less-expert sonographers could be reliable if adequately instructed.

Emerging drugs for primary Sjögren's syndrome

Introduction: Primary Sjögren's syndrome (pSS) is an autoimmune systemic disease characterized by a complex and not yet completely elucidated etiopathogenesis, where autoimmune manifestations coexist with different degree of lymphoproliferation, resulting in multiple possible scenarios extremely heterogeneous from patient to patient. Although considerable progress has been made in the identifications of potential novel therapeutic targets in recent years, the biological complexity of pSS, combined to such heterogeneous clinical manifestations, makes the treatment of pSS, even today, a great challenge. Areas covered: A therapy specifically approved for pSS is still lacking. In recent years, several novel promising agents are being tested in pSS. Based on a deep revision of drugs evaluated for pSS therapy, it is striking that several clinical trials, some of them testing very promising agents, failed. Expert opinion: a renewal of clinical trial design, including the definition of novel inclusion criteria and outcome measures, together with the development of a stratification model of pSS patients and the advance in the definition of pathogenetic mechanisms underlying peculiar pSS subsets, represent preliminary and crucial steps to overcome the current therapeutic impasse in pSS.

Histopathological changes in tear-secreting tissues and cornea in a mouse model of autoimmune disease

IMPACT STATEMENT

Cornea, an outermost layer of mammalian eye, is protected by tear film and abnormalities of tear film causes dry eye. Dry eye injures the cornea which results lower vision in patients. Several factors cause dry eye, including altered systemic conditions, environment, and immunological abnormality of the patient in autoimmune disease like Sjögren's syndrome (SS). However, the detailed pathology of autoimmune abnormality-mediated dry eye is unclear. Here we demonstrated that systemic autoimmune abnormality in BXSB-Yaa mice was associated with histological changes in the exocrine glands and cornea of the eyes. We also showed that BXSB-Yaa mice developed mild or early stage dry eye-like disease and explain the existence of a compensatory mechanism associated with the dysfunction of these tissues. Thus, BXSB-Yaa could be a model for SS-like disease-associated dry eye and these data would contribute to the understanding of the pathogenesis of autoimmune-related dry eye disease.

Predicting lymphoma outcomes and risk factors in patients with primary Sjögren's Syndrome using gradient boosting tree ensembles

Primary Sjogren's Syndrome (pSS) is a chronic autoimmune disease followed by exocrine gland dysfunction, where it has been long stated that 5% of pSS patients are prone to lymphoma development. In this work, we use clinical data from 449 pSS patients to develop a first, rule-based, supervised learning model that can be used to predict lymphoma outcomes, as well as, identify prominent features for lymphoma prediction in pSS patients. Towards this direction, the gradient boosting method combined with regression tree ensembles is used to derive a rule-based, decision model for lymphoma prediction. Our results reveal an average accuracy 87.1% and area under the curve score 88%, highlighting the importance of the C4 value, the rheumatoid factor and the lymphadenopathy factor as prominent lymphoma predictors, among others.

Predicting lymphoma development in patients with Sjögren's syndrome

Introduction: The issue of predicting lymphoma in primary Sjögren's syndrome (pSS) starts from its clinical and biologic essence, i.e., an autoimmune exocrinopathy with sicca syndrome, inflammation and lymphoproliferation of MALT (mucosa-associated lymphoid tissue) in exocrine glands. Areas covered: The two major predictors to be firstly focused are persistent salivary gland (SG) swelling and cryoglobulinemic vasculitis with related features as purpura and low C4, or the sole serum cryoglobulinemia repeatedly detected. They are pathogenetically linked and reflect a heavier MALT involvement by histopathology, with the expansion of peculiar rheumatoid factor (RF)-positive clones/idiotypes. Other predictors include lymphadenopathy, splenomegaly, neutropenia, lymphopenia, serum beta2-microglobulin, monoclonal immunoglobulins, light chains, and RF. Composite indexes/scores may also predict lymphoma. Expert opinion: Prediction at baseline needs amelioration, and must be repeated in the follow-up. Careful clinical characterization, with harmonization and stratification of large cohorts, is a relevant preliminary step. Validated and new biomarkers are needed in biologic fluids and tissues. SG echography with automatic scoring could represent a future imaging biomarker, still lacking. Scoring MALT involvement in pSS, as an additional tool to evaluate disease activity and possibly to predict lymphoma, is welcomed. All these efforts are now ongoing within the HarmonicSS project and in other research initiatives in pSS.

Treatment with belimumab restores B cell subsets and their expression of B cell activating factor receptor in patients with primary Sjogren's syndrome

OBJECTIVE

The aim of this study was to investigate the biological effects of belimumab on B cells in the first phase II open-label trial with belimumab in patients with primary SS (pSS) (BELISS).

METHODS

Peripheral blood B cell subsets and their B cell activating factor-receptor (BAFF-R) expression were analysed by multicolour flow cytometry in 10 pSS patients either before or after 24 and 52 weeks of therapy with belimumab. Serum BAFF levels were analysed by ELISA.

RESULTS

At baseline, pSS patients showed a significant increase in circulating B cells compared with healthy donors matched for age and sex, with a predominant expansion of transitional and naive B cell subsets. pSS patients also showed higher serum BAFF levels and lower B cell BAFF-R expression. Therapy with belimumab in pSS patients induced a significant reduction in transitional and naive B cell subsets to levels similar to those observed in healthy donors. Furthermore, belimumab normalized BAFF-R expression in all B subsets comprised within the memory compartment. The restoration of B cell frequency and subset composition in response to belimumab was also associated with a decrease in serum levels of Ig, RF, ANAs, and with an increase in the C4 complement fraction. All of these belimumab-mediated effects were observed after 24 weeks of therapy and maintained until the end of the therapeutic protocol.

CONCLUSION

Taken together, our findings show that targeting BAFF with belimumab is successful in normalizing B cell frequency, phenotype and functions in pSS.

TRIAL REGISTRATION

clinicaltrials.gov; https://clinicaltrials.gov/; NCT01008982.

Primary Localized Cutaneous Nodular Amyloidosis in a Patient with Sjögren's Syndrome: A Review of the Literature

We report a 53-year-old Japanese woman with multiple, red, and elastic soft nodules on the left waist, left thigh, and right lower leg. She had had polyclonal hyperglobulinemia for one year, rheumatoid arthritis for 13 years, and Sjögren's syndrome (SjS) for 18 years. Histochemical examination of the nodule on the left thigh revealed a deposition of amyloid by Congo red staining. It was also positively stained with both anti-kappa and -lambda light chain antibodies. Moreover, the cytoplasm of the infiltrating plasma cells also positively reacted to both antibodies. The major amyloid proteins of primary localized cutaneous nodular amyloidosis (PLCNA) generally consist of monoclonal immunoglobulin light chains. A review of literature demonstrates 13 cases of PLCNA with SjS, in which immunoglobulin light chains were demonstrated in the amyloid in 5 cases. Amyloid in the 3 cases was composed of a single class immunoglobulin light chain and that in the 2 cases was composed of both kappa and lambda light chains. Polyclonal immunoglobulin amyloid has been reported only in PLCNA with SjS, which may be related to the fact that a certain population of SjS develops polyclonal B cell proliferation and hyperglobulinemia.

Pulmonary AL amyloidosis in a patient with primary Sjögren syndrome

Abstract The condition of a 29-year-old woman with primary Sjögren syndrome (SS) was complicated by amyloid light chains- (AL-) type amyloidosis in the paranasal sinus. She had not complained of respiratory symptoms, but her chest computed tomography (CT) scan revealed bilateral multiple nodular shadows. Lung biopsy specimens using video-associated thoracoscopy showed amyloidoma in a subpleural nodular lesion and amyloid deposits in the interstitial parenchymal walls and pulmonary vessels. Pulmonary AL amyloidosis, presumably related to a chronic inflammatory lymphoproliferative process in SS, has rarely been reported.

Lymphoma development in patients with autoimmune and inflammatory disorders--what are the driving forces?

For decades, it has been known that patients with certain autoimmune and inflammatory disorders, such as rheumatoid arthritis (RA) and primary Sjögren's syndrome (pSS), have an increased risk of developing malignant lymphoma. Although the clinico-biological reasons for this association remain largely unknown, our knowledge has improved and new insights have been obtained. First, the direct link between autoimmunity and lymphomagenesis has been strengthened by large epidemiological studies showing a consistent risk increase of lymphoma associated with certain autoimmune/inflammatory conditions in independent cohorts from different countries. Second, a number of local and systemic disease-related risk factors in these diseases have been repeatedly linked to lymphoma development, with the prime examples being disease severity and the degree of inflammatory activity. Considering the key role of B- and T-cell activation in the pathogenesis of both autoimmunity and lymphoma, it is perhaps not surprising that longstanding chronic inflammation and/or antigen stimulation have emerged as major predisposing factors of lymphoma in patients with active autoimmune disease. Finally, increasing evidence suggests that lymphomas associated with autoimmunity constitute a different spectrum of entities compared to lymphomas arising in patients without any known autoimmune or inflammatory conditions, pointing to a different pathobiology. In this review, we summarize the recent literature that supports a direct or indirect link between immune-mediated disease and lymphoma and describe the characteristics of lymphomas developing in the different diseases. We also discuss molecular, genetic and microenvironmental factors that may come into play in the pathobiology of these disorders.

The important role of T cells and receptor expression in Sjögren's syndrome

Sjögren's syndrome (SjS), an autoimmune disease characterized by exocrine gland dysfunction leading to dry mouth and dry eye diseases, is typified by progressive leucocyte infiltrations of the salivary and lacrimal glands. Histologically, these leucocyte infiltrations generally establish periductal aggregates, referred to as lymphocytic foci (LF), which occasionally appear as germinal centre (GC)-like structures. The formation and organization of these LF suggest an important and dynamic role for helper T cells (TH), specifically TH1, TH2 and the recently discovered TH17, in development and onset of clinical SjS, considered a B cell-mediated hypersensitivity type 2 disease. Despite an ever-increasing focus on identifying the underlying aetiology of SjS, defining factors that initiate this autoimmune disease remain a mystery. Thus, determining interactions between infiltrating TH cells and exocrine gland tissue (auto-)antigens represents a fertile research endeavour. This review discusses pathological functions of TH cells in SjS, the current status of TH cell receptor gene rearrangements associated with human and mouse models of SjS and potential future prospects for identifying receptor-autoantigen interactions.

The Interferon-Signature of Sjögren's Syndrome: How Unique Biomarkers Can Identify Underlying Inflammatory and Immunopathological Mechanisms of Specific Diseases

Innate immune responses direct the nature and specificity of downstream adaptive responses in autoimmune diseases. One of the strongest markers of innate immunity is the up-regulated expression of interferon (IFN) and IFN-responsive/stimulated genes (IRGs/ISGs). While multiple IRGs are induced during the innate phase of host responses, transcriptome data suggest unique IRG-signatures for different diseases. Sjögren's syndrome (SjS) is characterized by chronic immune attacks against exocrine glands leading to exocrine dysfunction, plus strong up-regulated expressions of IFN IRG transcripts. Genome-wide transcriptome analyses indicate that differentially expressed IRGs are restricted during disease development and therefore define underlying etiopathological mechanisms. Here we review the innate immune-associated IFN-signature of SjS and show how differential gene expressions of IRG/ISG sets interact molecularly and biologically to identify critical details of SjS etiopathogenesis.

Possible Mechanisms of Lymphoma Development in Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a systemic as well as an organ-specific autoimmune disease characterized by lymphocytic infiltration of the glandular epithelial tissue. SS patients have been reported to be at highest risk of developing lymphoproliferative neoplasms, when compared with patients with other rheumatoid diseases. Factors such as cytokine stimulation, environmental factors, viral infection and genetic events as well as vitamin deficiency may contribute to the development of lymphoma. Over the past few decades, numerous efforts have been made to assess the relationship between lymphoma and SS. These include epidemiological surveys, molecular biologic assessments of clonality and well-linked register cohort studies evaluating the predictive value of clinical, laboratory and histological findings. Nevertheless, the mechanisms and factors predictive of lymphoma development in pSS patients remain to be defined. This review summarizes updated knowledge on the incidence of and risk factors for lymphoma development in pSS patients, as well as discussing the most recent findings on the development and treatment of lymphoma in pSS patients and the possible mechanism of lymphoma development.

BXSB/MpJ-Yaa mice develop autoimmune dacryoadenitis with the appearance of inflammatory cell marker messenger RNAs in the lacrimal fluid

BACKGROUND

Dacryoadenitis is characteristic of an autoimmune exocrinopathy, e.g. Sjögren syndrome. We pathologically examined the lacrimal glands of autoimmune-prone BXSB/MpJ-Yaa mice for the appearance of pathological signs of dacryoadenitis progression in autoimmune dacryoadenitis models, particularly focusing on messenger RNAs in the lacrimal fluid.

METHODS

The lacrimal glands of the BXSB/MpJ-Yaa and C57BL/6 mice were histopathologically analyzed in parallel with the evaluation of lacrimation and messenger RNA expression of water channels (Aqp3, Aqp4 and Aqp5). In addition, autoimmune model mice (MRL/MpJ-lpr/lpr and NZB/NZWF1) were used for evaluating cell infiltration and detecting inflammatory cell marker messenger RNAs (Cd68, Ptprc and Cd3e) in the lacrimal fluids by polymerase chain reaction-based methods.

RESULTS

B-cell predominant lymphocytic infiltrations and the destruction of acini were observed in the lacrimal glands of BXSB/MpJ-Yaa mice. There was no significant difference in the quantity of lacrimal fluid between the BXSB/MpJ-Yaa and C57BL/6 mice. In the BXSB/MpJ-Yaa mice, Aqp3 expression increased significantly with the cell infiltration score, whereas expression of Aqp4 and Aqp5 tended to decrease. Aqp3 expression increased significantly with the cell infiltration score in BXSB/MpJ-Yaa mice. Among inflammatory cell markers, Cd68 was more frequently detected in the lacrimal fluid of the BXSB/MpJ-Yaa, MRL/MpJ-lpr/lpr and NZB/NZWF1 mice than in that of the C57BL/6 mice.

CONCLUSION

BXSB/MpJ-Yaa mice clearly developed autoimmune dacryoadenitis. The altered expression of water channels in lacrimal glands might be associated with the preservation of lacrimal fluid excretion in BXSB/MpJ-Yaa mice. The detection of inflammatory cell markers in lacrimal fluid could be used as a diagnostic marker for autoimmune dacryoadenitis.

Gastrointestinal and hepatic manifestations of Sjogren syndrome

Sjogren syndrome (SS) is an autoimmune disease that affects exocrine glands and therefore may affect the gastrointestinal system, from the mouth, esophagus, and bowel to the liver and pancreas. Oral involvement in SS is mainly characterized by dryness, with a wide spectrum of symptoms, from mild-to-severe xerostomia with dysgeusia and tooth decay. The dysphagia, although common, does not correlate with the reduced salivary flow rate or the dysmotility that may be present. Dyspepsia, found in up to 23% of patients, may be associated with gastritis, reduced acid production, and antiparietal cell antibodies, but rarely pernicious anemia. Pancreatic involvement, although rare, includes pancreatitis and pancreatic insufficiency. The most common causes of liver disease are primary biliary cirrhosis, autoimmune hepatitis, nonalcoholic fatty liver disease, and hepatitis C virus (HCV). Although abnormal liver tests are found in up to 49% of patients, they are usually mild. Although sicca syndrome, abnormal histology of the salivary glands, and abnormal sialograms are common in primary biliary cirrhosis, the antibodies to Ro/SSA or La/SSB antigens are infrequent. Xerostomia, sialadenitis, abnormal salivary flow rates, and abnormal Schirmer test in HCV vary widely among the studies, although the antibodies to Ro/SSA or La/SSB are only 1%. Several studies show that HCV is in saliva, although how this may impact sicca syndrome or SS in HCV is unclear. SS as a disease of exocrine glands affects many parts of the gastrointestinal system.

Cryoglobulinaemia related to Sjogren's syndrome or HCV infection: differences based on the pattern of bone marrow involvement, lymphoma evolution and laboratory tests after parotidectomy

OBJECTIVE

The relationship of cryoglobulinaemia with lymphoproliferation of mucosa-associated lymphoid tissue (MALT) as risk factors for lymphoma evolution in SS remains to be clarified. The different biologic background of SS-related cryoglobulinaemia as compared with cryoglobulinaemia linked to HCV infection was clarified by different clinical and biologic approaches.

METHODS

B-cell clonal expansion was analysed in the bone marrow of 27 consecutive cases with primary SS and mixed cryoglobulinaemia, HCV unrelated, in comparison with 55 HCV-related patients with cryoglobulinaemic vasculitis (CV) without SS. The results were related to the possible occurrence and localization of B-cell lymphoma in the single case. Secondly, the prevalence of mixed cryoglobulinaemia was investigated in 41 unselected patients with primary SS showing either parotid myoepithelial sialadenitis (MESA) or a frank B-cell non-Hodgkin's lymphoma. Thirdly, the levels of serum cryoglobulins and RF were followed in one patient with primary SS, CV and parotid B-cell lymphoma of MALT after bilateral subtotal parotidectomy.

RESULTS

A polyclonal pattern of B expansion in the bone marrow was significantly more frequent in SS-related (19/27 cases) than in HCV-related cryoglobulinaemia (19/55) (P = 0.003). Cryoglobulins were positive in a fraction of patients with SS and malignant lymphoma or with parotid MESA (13/18 and 7/23, respectively), whereas MALT involvement by the lymphoproliferative disorder was the rule. Finally, the levels of serum cryoglobulins and RF markedly decreased in the SS patient undergoing bilateral subtotal parotidectomy.

CONCLUSION

Lymphoproliferation of MALT appears as the biologic background of cryoglobulinaemia in SS, differently from HCV-related cryoglobulinaemia.

Immunopathologic differences of Sjögren's syndrome versus sicca syndrome in HCV and HIV infection

A clinical picture of dry eye and dry mouth with the histological counterpart of focal lymphocytic sialoadenitis, usually detected in minor salivary glands, is considered the hallmark of Sjögren's syndrome. The association of sicca complaints and focal sialoadenitis can be also found in a number of other diseases, including some systemic viral infections. Among these conditions, chronic hepatitis C virus infection, associated with mixed cryoglobulinaemia and extra-hepatic manifestations, and HIV infection, particularly in the phase of diffuse interstitial lymphocytic infiltration, may mimic the clinical and histological aspects of Sjögren's syndrome. However, each disorder is characterised by specific, disease-related immunopathological aspects. Besides sicca complaints, the various disorders may also share a number of systemic extra-glandular features and the possible development of mucosa-associated lymphoid tissue lymphomas. This latter event represents in all of these diseases the final result of an antigen-driven chronic stimulation of B lymphocytes.

Risk, predictors, and clinical characteristics of lymphoma development in primary Sjögren's syndrome

OBJECTIVE

To assess the risk and predictors of lymphoma development in a large cohort of patients with primary Sjögren's syndrome (pSS).

METHODS

Cox-regression analyses were used to study the predictive value of clinical and laboratory findings at pSS diagnosis, and Kaplan-Meier survival curves to compare survival probability between patients who developed lymphoma and the total cohort. Expected risk for lymphoma was calculated by comparison with the background population.

RESULTS

Eleven (4.5%) from 244 patients developed a non-Hodgkin lymphoma (NHL). Diffuse large B-cell and mucosa-associated lymphoid tissue lymphomas occurred at a similar frequency. Three (27.3%) patients died: 2 due to transformation from mucosa-associated lymphoid tissue to diffuse large B-cell. Purpura (HR 8.04, 95% confidence interval [CI] 2.33-27.67), parotidomegaly (HR 6.75, 95%CI 1.89-23.99), anemia (HR 3.43, 95%CI 1.04-11.35), leukopenia (HR 8.70, 95%CI 2.38-31.82), lymphocytopenia (HR 16.47, 95%CI 3.45-78.67), hypergammaglobulinemia (HR 4.06, 95%CI 1.06-15.58), low C3 (HR 36.65, 95%CI 10.65-126.18), and low C4 (HR 39.70, 95%CI 8.85-126.18) levels at pSS diagnosis were significant predictors of NHL development, but only hypocomplementemia and lymphocytopenia were independent risk factors. Hypocomplementemia was related to earlier development of NHL and higher mortality. The cumulative risk of developing lymphoma ranged from 3.4% in the first 5 years to 9.8% at 15 years. Standardized incidence ratio (95%CI) for NHL development was 15.6 (95%CI 8.7-28.2).

CONCLUSIONS

Patients with pSS have a 16-fold increased risk of developing lymphoma. This risk increases with time. Hypocomplementemia and lymphocytopenia at pSS diagnosis are the strongest predictors. Survival is clearly reduced in patients with hypocomplementemia. Indolent lymphomas tend to evolve over time toward a more aggressive histologic type.

Controversies on rituximab therapy in sjögren syndrome-associated lymphoproliferation

Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by chronic inflammation of salivary and lachrymal glands, and frequently accompanied by systemic symptoms. A subgroup of SS patients develops malignant B cell non-Hodgkin's lymphoma (NHL), usually of the mucosa-associated lymphoid tissue (MALT) type and very often located in the major salivary glands. Currently, there is a lack of evidence-based intervention therapy which may influence SS-related chronic inflammation and lymphoproliferation. B cells are involved in the pathogenesis of SS, and B cell downregulation may lead to a decrease of disease activity. Rituximab (RTX), a chimeric monoclonal antibody targeting the CD20 antigen on the B cell surface, has been successfully investigated in other autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, ANCA-associated vasculitis, and mixed cryoglobulinemic syndrome. Preliminary experiences of RTX therapy in SS patients with or without a lymphoproliferative disorder suggest that SS patients with more residual exocrine gland function might better benefit from RTX. Efficacy of RTX in SS-associated B-cell lymphoma, mainly in low-grade salivary gland lymphomas, remains an open issue.

Sjögren's syndrome: an old tale with a new twist

Sjögren's syndrome (SjS) is chronic autoimmune disease manifested by the loss of saliva and/or tear secretion by salivary and/or lacrimal glands, respectively. The pathogenesis of the disease remains elusive, perhaps due to the multiple triggers of the disease. However, substantial advances have been made in attempting to resolve the complexity of SjS using both animal models and human subjects. The primary objectives of this review are to provide a better understanding of the disease processes with major emphasis on the use of mouse models, how genetic predisposition plays a role in the natural history of the disease, as well as a presentation of new findings pertaining to the role of T(H)1, T(H)2, and T(H)17 cells in the pathogenesis of SjS.

Is the blood B-cell subset profile diagnostic for Sjogren syndrome?

Objective:

To evaluate the relevance of the blood B-cell subset profile for the diagnosis of Sjögren syndrome.

Methods:

The distribution of mature blood B cells from Bm1 through Bm5 was determined in 161 patients, of whom 25 fulfilled the American–European Consensus Group criteria for primary SS (pSS), and 136 served as disease controls.

Light-chain-restricted germinal centres in reactive lymphadenitis: report of eight cases

AIMS

Light-chain-restricted germinal centres are generally associated with the existence of a neoplastic lymphoproliferative disorder. The aim was to present a series of cases with persistent lymph node enlargement that featured some germinal centres showing light chain immunoglobulin restriction.

METHODS AND RESULTS

A series of six reactive lymphadenitis and two Castleman's disease cases was analysed by immunohistochemistry, IgH-polymerase chain reaction (PCR) and microdissected PCR. In all cases some germinal centres contained a population of plasma cells and plasmacytoid germinal centre cells showing light chain immunoglobulin restriction. In three cases the monotypic cells also showed distinct Bcl-2 expression. Two of the cases showed a predominant IgH rearrangement on a florid polyclonal background and one had an IgH monoclonal rearrangement, as revealed by PCR. Microdissected germinal centre PCR revealed a dominant repeated band in one of three cases and in another case a non-repeated clonal peak was observed. One of the patients developed a follicular lymphoma, which became evident from a subsequent biopsy.

CONCLUSIONS

These findings may be a manifestation of an underlying disorder in the regulation of the immune response, or an exaggeration of the germinal centre oligoclonal nature. This should be taken into account in the differential diagnosis of follicular hyperplasia.

Clinical, immunologic, and molecular factors predicting lymphoma development in Sjogren's syndrome patients

Among autoimmune diseases, Sjogren's syndrome (SS) displays the highest incidence of non-Hodgkin lymphoma (NHL) development with the salivary extranodal marginal zone B cell lymphomas being the most common type. The majority of SS-associated NHLs are characterized by localized stage, indolent clinical course, and recurrence in other extranodal sites. Although the transition from a chronic inflammatory condition to malignant lymphoma is a multistep process yet poorly understood, there is increasing evidence that chronic antigenic stimulation by an exoantigen or autoantigens plays an essential role in the development of SS associated lymphoproliferation. Additional molecular oncogenic events such as microsatellite instability, loss of the B cell cycle control, and the forced overproduction of specific B cell biologic stimulators seem to contribute to the emergence and progression of the malignant overgrowth. Among the clinical and serological parameters that have been associated with lymphoma development in SS patients, the presence of palpable purpura, low C4, and mixed monoclonal cryoglobulinemia constitute the main predictive markers, and patients displaying these risk factors should be monitored closely.

Clonal expansion of immunoglobulin M+CD27+ B cells in HCV-associated mixed cryoglobulinemia

Hepatitis C virus (HCV) is associated with B-cell lymphoproliferative disorders such as mixed cryoglobulinemia (MC) and B-cell non-Hodgkin lymphoma (B-NHL). The pathogenesis of these disorders remains unclear, and it has been proposed that HCV drives the pro-liferation of B cells. Here we demonstrate that certain HCV(+)MC(+) subjects have clonal expansions of immunoglobulin M (IgM)(+)kappa(+)IgD(low/-)CD21(low)CD27(+) B cells. Using RT-PCR to amplify Ig from these singly sorted cells, we show that these predominantly rheumatoid factor-encoding V(H)1-69/J(H)4 and V(kappa)3-20 gene segment-restricted cells have low to moderate levels of somatic hypermutations. Ig sequence analysis suggests that antigen selection drives the generation of mutated clones. These findings lend further support to the notion that specific antigenic stimulation leads to B-cell proliferation in HCV MC and that chronic B-cell stimulation may set the stage for malignant transformation and the development of B-NHL. The finding that these hypermutated, marginal zone-like IgM(+)CD27(+) B cells are clonally expanded in certain subjects with MC offers insight into mechanisms of HCV-associated MC and B-cell malignancy. This study was registered at www.clinicaltrials.gov as NCT00219999.

Clonality analysis of lymphoproliferative disorders in patients with Sjögren's syndrome

The aim of this study was to clarify the nature of the clonal lymphocyte infiltration in Sjögren's syndrome (SS) patients associated with lymphoproliferative disorders. We examined B cell clonality in lymphoproliferative tissues from six primary SS patients associated with lymphoproliferative disorders or lymphoma by cloning and sequencing of the gene rearrangement of the immunoglobulin heavy chain complementarity determining region 3 (IgVH-CDR3). Three patients with sequential observation showed progressional clonal expansion with the presence of the same subclone in different tissues during the course of disease. Among them, one patient developed mucosa-associated lymphoid tissue (MALT) lymphoma in glandular parotid. The other three SS patients concomitant with malignant B cells lymphomas showed different clonal expansion of B cells between nodal sites and salivary glands. The cloanality analysis indicated that monoclonal B cell population could spread from one glandular site to another site during the course of SS, suggesting that the malignant clone may arise from the general abnormal microenvironment, not restricted to the glandular tissue, in some SS patients.

Rituximab in mixed cryoglobulinemia: increased experience and perspectives

Type II mixed cryoglobulinemia syndrome (MCsn) is a systemic vasculitis mainly linked to immune complex deposition in several organs and to hepatitis C virus (HCV) infection. Therapeutic strategies can target either the viral trigger HCV if present, or pathogenic events downstream the triggering infection, e.g, the proliferating B-cells directly. Antiviral therapy should be considered as first-line treatment in many HCV-positive patients. However, it may prove ineffective, contraindicated, or poorly tolerated. On the other hand, the other available treatments (such as cytotoxic agents, plasma exchange and steroids) may lead to life-threatening complications and may be difficult to manage in the long term. Given the good safety profile in lymphomas, rituximab (RTX) has been used off-label for numerous patients suffering from a variety of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis/ polymyositis, and anti-neutrophil cytoplasmic antibody (ANCA)-positive vasculitis. Efficacy and safety of RTX in MCsn and in particular in MCsn-related glomerulonephritis was recently described. Based on these results, a multicentre, controlled, randomised, clinical trial is now ongoing to compare RTX versus the best available treatments in some severe MCsn manifestations (i.e. skin ulcers, sensory and/or motor neuropathy and active glomerulonephritis).

Malignant lymphomas in autoimmunity and inflammation: a review of risks, risk factors, and lymphoma characteristics

Certain autoimmune and chronic inflammatory conditions, such as Sjögren's syndrome and rheumatoid arthritis (RA), have consistently been associated with an increased risk of malignant lymphomas, but it is unclear whether elevated lymphoma risk is a phenomenon that accompanies inflammatory conditions in general. Likewise, it is debated whether the increased risk identified in association with some disorders pertains equally to all individuals or whether it varies among groups of patients with different phenotypic or treatment-related characteristics. It is similarly unclear to what extent the increased lymphoma occurrence is mediated through specific lymphoma subtypes. This update reviews the many findings on risks, risk levels, and lymphoma characteristics that have been presented recently in relation to a broad range of chronic inflammatory, including autoimmune, conditions. Recent results clearly indicate an association between severity of chronic inflammation and lymphoma risk in RA and Sjögren's syndrome. Thus, the average risk of lymphoma in RA may be composed of a markedly increased risk in those with most severe disease and little or no increase in those with mild or moderate disease. The roles of immunosuppressive therapy and EBV infection seem to be limited. Furthermore, RA, Sjögren's syndrome, systemic lupus erythematosus, and possibly celiac disease may share an association with risk of diffuse large B-cell lymphoma, in addition to well-established links of Sjögren's syndrome with risk of mucosa-associated lymphoid tissue lymphoma and of celiac disease with risk of small intestinal lymphoma. However, there is also obvious heterogeneity in risk and risk mediators among different inflammatory diseases.

Dissemination of a Sjögren's syndrome-associated extranodal marginal-zone B cell lymphoma: circulating lymphoma cells and invariant mutation pattern of nodal Ig heavy- and light-chain variable-region gene rearrangements

OBJECTIVE

Both the genesis and outgrowth of extranodal marginal-zone B cell lymphomas (MZLs) of the mucosa-associated lymphoid tissue (MALT) type are generally thought to represent antigen-driven processes. We undertook this study to analyze lymphoma progression and dissemination outside of the MALT-type lesions.

METHODS

Histopathologic and Ig heavy- and light-chain variable-region gene (V(H/L)) analyses were performed in sequential tissue samples from a patient with primary Sjögren's syndrome (SS) with glandular (parotid) manifestations and subsequent nodal dissemination of a low-grade MZL.

RESULTS

This MZL expressed a CD20+,CD27+,sIgM/kappa+,IgD-,CD5-,CD10-,Bcl-6-,CD23-,p53-,p21-,MDM2- phenotype and mutated V(H)1-69/D2-21/J(H)4alpha-V(kappa)A27/J(kappa)2 Ig rearrangements. Notably, circulating lymphoma cells from the parotid glands occurred transiently in the patient's blood, as detected by single-cell polymerase chain reaction. In addition, 2 minor B cell clones (clones 2 and 3, with V(H)3-07/D3-22/J(H)3b-V(lambda)3L/J(lambda)2/3 and V(H)3-64/D3-03/J(H)2-V(kappa)A19/J(kappa)2 rearrangements, respectively) were also detected in the parotid glands and blood, and 1 of these (clone 2) was also detected in the lymph nodes. Ig V(H/L) analyses revealed ongoing (antigen-driven) mutations of the glandular lymphoma rearrangements, but an invariant mutation pattern of their nodal counterparts.

CONCLUSION

These data indicate coexpansion and transient (re)circulation of the lymphoma clone and 2 additional glandular B cell clones in a primary SS-associated extranodal MZL. Combined histologic and molecular features of the nodal lymphoma subclone reflect a process of "follicular colonization" that eventually froze the mutation machinery after accumulation of additional (antigen-driven) Ig V(H/L) mutations.

Identification of transitional type II B cells in the salivary glands of patients with Sjögren's syndrome

OBJECTIVE

To identify B cell subpopulations participating in the lymphocyte infiltrate of salivary glands from patients with primary Sjögren's syndrome. A special emphasis was placed on those B lymphocytes included in the ectopic germinal centers (GCs).

METHODS

The presence of B cells in salivary glands and their polyclonality were ascertained by phenotyping and reverse transcription-polymerase chain reaction in salivary gland samples from 18 patients. Their phenotype was thoroughly analyzed using a number of double-staining combinations. The results obtained in tissue sections were confirmed by fluorescence-activated cell sorting analysis of B cells eluted from salivary glands, and these findings were compared with those in tonsils.

RESULTS

Memory-type B cells were defined as CD20+, CD27+ and were seen in all specimens, whereas GCs were found in only 7 specimens. Furthermore, B cells found in these GCs lacked certain characteristics of centroblasts and centrocytes. Instead, they fulfilled the criteria for transitional type II (TII) B cells and resembled marginal-zone B cells. BAFF (the assistance of which is required for proper transformation of transitional TI B cells into transitional TII B cells) accumulated adjacent to transitional and marginal-zone-like B lymphocytes. Further evidence for the involvement of BAFF came from the expression of its receptors on infiltrating B cells.

CONCLUSION

These transitional TII and marginal-zone-like B cells are probably instrumental in the local production of autoantibodies and possibly influential in the ensuing destruction of epithelial cells.