Renal involvement in primary Sjögren syndrome

Growth arrest-specific protein 6 as a marker of nephritis in systemic sclerosis and juvenile systemic lupus erythematosus patients

Background: Renal impairments commonly occur as a complication of autoimmune connective tissue diseases (CTDs). Therefore, early nephritis prediction is vital for patient outcomes. Growth Arrest-Specific Protein 6 (GAS6) was found to be upregulated in many types of inflammatory renal disease, including diabetic nephropathy.Aim: To evaluate GAS6 as a predictor of renal impairment in adults with systemic sclerosis (SSc) and children with systemic lupus Erythematosus (SLE).Methods: The study included 60 patients with SSc and 40 children with SLE. The serum level of GAS6 was measured using the ELISA technique. In adults with SSc, total proteins in 24-h urine concentration of >300 mg/24 h indicated renal inflammation, while in children with SLE, nephritis was diagnosed by abnormal renal pathology.Results: In SSc patients, GAS6 significantly increased in patients with proteinuria. GAS6 is an independent predictor of nephritis with an odds ratio (OR) of 1.06 and a 95% confidence interval (CI) of 1.0-1.1. at cutoff 12.2 ng/mL GAS6 predicted proteinuria with sensitivity 86.7% (95% CI: 59.5% to 98.3%), specificity 57.8% (95% CI: 42.1% to 72.3%), positive predictive value 40.6% (95% CI: 31.5% to 50.4%), negative predictive value 92.9% (95% CI: 77.7% to 97.73%), and accuracy 65.0% (95% CI: 51.6% to 76.9%). In SLE patients, Serum GAS6 did not differ significantly between children with and without lupus nephritis.Conclusion: GAS6 is an independent predictor of nephritis in patients with SSc. However, there is no association between GAS6 and nephritis in juvenile patients with SLE.

Hypokalemic quadriplegia in Sjogren's syndrome: A case report

Key Clinical Message

In managing Sjogren's syndrome, a thorough patient history, proper lab tests, and imaging are crucial. Clinicians should prioritize checking electrolyte levels in cases of muscle weakness, as early detection of hypokalemia can prevent severe complications. Proactive monitoring can avert renal tubular acidosis and improve patient outcomes.

Abstract

Distal renal tubular acidosis (dRTA) occurs in approximately one-third of patients with Sjogren's syndrome, a systemic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands, leading to dryness of mucous membranes. Hypokalemic paralysis, a well-documented but rare complication of dRTA, typically manifests as symmetric proximal muscle weakness of the extremities. We present the case of a 38-year-old woman with a history of Sjogren's syndrome diagnosed 3 years prior, who ceased her medication without medical supervision. She presented with quadriplegia, initially beginning unilaterally. This particular presentation is seldom documented in the literature. Laboratory investigations revealed hypokalemia and normal anion gap metabolic acidosis, consistent with dRTA-induced hypokalemic paralysis. Intravenous potassium chloride was administered, resulting in complete recovery of muscle strength. Hypokalemic paralysis associated with dRTA is typically reversible; however, delays in diagnosis and treatment can lead to life-threatening complications such as respiratory failure and arrhythmias. Therefore, clinicians should maintain a high index of suspicion for this condition in patients presenting with muscle weakness. Prompt and precise history takingand screening, and initiating appropriate management to prevent adverse outcomes.

Polyarthritis in Sjögren's Syndrome: Difficulties in Distinguishing Extraglandular Manifestation and Associated Rheumatoid Arthritis

Aim of the study was to investigate the demographic data and disease course characteristics of patients with Sjögren's syndrome (SS) and inflammatory joint pain of various origins and to search for factors that might help with the distinction of polyarthritis as an extraglandular manifestation and rheumatoid arthritis as an associated systemic autoimmune disorder. A total of 355 patients were retrospectively analyzed, 128 of whom served as controls (SS-C), while 159 had polyarthritis as an extraglandular symptom of Sjögren's syndrome (SS-pa) and 68 were diagnosed as having associated rheumatoid arthritis (SS-RA). The patients without any inflammatory joint manifestations were significantly older than the SS-pa patients, while, for the SS-RA group, the difference was not significant. The onset of joint pain appeared significantly earlier in the SS-RA patients. Regarding either extraglandular manifestations or associated autoimmune disorders, there were significant differences between the controls and both SS-pa and SS-RA groups, while no significant difference was found between the SS-pa and SS-RA groups. Thus, laboratory and imaging methods should be used to differentiate between the two conditions, but laboratory biomarkers are even more important for early diagnosis. A ROC curve analysis showed an acceptable diagnostic accuracy in differentiating between SS-pa and SS-RA patients using a binary logistic regression model, where highly positive rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) values, kidney involvement, and anti-Ro/SS-A positivity were shown to significantly raise the odds of having RA, whereas anti-La/SS-B positivity seemed to have a protective role, since it significantly decreased the odds of having it. Further biomarkers are needed to better classify SS patient cohorts with inflammatory joint pain of different origins and, consequently, different management requirements.

Advances in cellular and molecular pathways of salivary gland damage in Sjögren's syndrome

Sjögren's Syndrome (SS) is an autoimmune disorder characterized by dysfunction of exocrine glands. Primarily affected are the salivary glands, which exhibit the most frequent pathological changes. The pathogenesis involves susceptibility genes, non-genetic factors such as infections, immune cells-including T and B cells, macrophage, dendritic cells, and salivary gland epithelial cells. Inflammatory mediators such as autoantibodies, cytokines, and chemokines also play a critical role. Key signaling pathways activated include IFN, TLR, BAFF/BAFF-R, PI3K/Akt/mTOR, among others. Comprehensive understanding of these mechanisms is crucial for developing targeted therapeutic interventions. Thus, this study explores the cellular and molecular mechanisms underlying SS-related salivary gland damage, aiming to propose novel targeted therapeutic approaches.

Hypocitraturia as a biomarker of renal tubular acidosis in patients with Sjögren's disease

INTRODUCTION

Sjögren's disease (SD) is an immune-mediated chronic inflammatory disease that affects epithelial tissues, mainly salivary and lacrimal glands. It also presents extraglandular manifestations. The main renal manifestation is tubulointerstitial nephritis (TIN), which can manifest as renal tubular acidosis (RTA). Urinary citrate may be a biomarker of RTA in these patients. The objective of this study was to evaluate whether hypocitraturia is a predictive biomarker of RTA in a sample of patients with SD in a tertiary hospital in southern Brazil.

METHODS

All patients with SD who met the inclusion criteria and who participated in the rheumatology outpatient clinic of the Irmandade Santa Casa de Misericórdia de Porto Alegre were included. Demographic, SD, serological and urinary data were obtained. RTA was considered in those patients who persistently presented urinary pH above 5.5 and serum pH below 7.35. Patients who persistently had urinary pH above 5.5 underwent a urinary acidification test with furosemide and fludrocortisone. These patients received 1 mg of fludrocortisone and 40 mg of furosemide and had their urine samples tested 2, 4 and 6 h after taking the medications. The test was stopped at any urine sample with pH 5.5 or less. The variables were expressed as mean and standard deviation or interquartile range. The association between hypocitraturia and RTA was assessed using the chi-square.

RESULTS

Forty-two patients were included, 95.2% female with a median age of 61.73 years. The prevalence of complete distal RTA was 4.88%. Twenty-eight patients underwent urine acidification testing. Five patients had hypocitraturia, and two of them had complete distal RTA. The association between hypocitraturia and RTA was statistically significant (p < 0.012), with a sensitivity of 100%, specificity of 91.2% and accuracy of 91.7%. The negative predictive value was 100%. The global renal assessment of the population demonstrated two patients with RTA, one patient with decreased renal function and six patients with proteinuria greater than 0.5 g/24 h.

CONCLUSION

The prevalence of RTA in the studied population was 4.88%. Hypocitraturia had high sensitivity and accuracy for the diagnosis of RTA.

Invisible, Uncontrollable, Unpredictable: Illness Experiences in Women with Sjögren Syndrome

Background/Objectives: Sjögren's Syndrome (SS) is a chronic degenerative rheumatic disease. Because of its chronic nature, it significantly affects the quality of life of those who suffer from it. Methods: This qualitative study investigated disease experience among women suffering from SS to understand its impact on their overall well-being. In-depth interviews were conducted with 15 women who suffer from SS. Interviews were analyzed using the Grounded Theory methodology, using open, axial, and selective coding. Results: Three central phenomena of disease experience were identified: invisibility; uncontrollability; and unpredictability. Conclusions: SS disease experience has a strong imprint on emotional well-being and sense of self-control among middle-aged women. Understanding SS impacts on women's lives is important to better understand the disease and contribute to recognizing potential areas of management and social support in relevant windows of opportunity within the health-disease continuum.

Acquired disorders of phosphaturia: Beyond tumor-induced osteomalacia

Phosphate is an integral part of human cellular structure and function. Though most recognised disorders of phosphaturia are genetic in origin, phosphate loss due to acquired conditions is commonly encountered in clinical practice. Acquired hypophosphatemia is most commonly due to renal phosphate wasting and can produce significant morbidity. It also heralds future kidney damage, and continued exposure can lead to progressive kidney injury and potentially renal failure. These conditions are a diverse group of disorders with common shared mechanisms causing loss of phosphate in the urine. Renal phosphate loss can occur as an isolated entity or as a part of generalised proximal tubular dysfunction, i.e., Fanconi's syndrome. An insight into the pathophysiological mechanisms of acquired phosphaturia can help clinicians monitor their patients better and avoid potential harms.

Kidney manifestations of pediatric Sjögren's syndrome

Approximately 1% of all patients with Sjögren's syndrome (SS) are children. Unlike the adult form, in which sicca syndrome is the main presentation, in children, the most common clinical finding is recurrent enlargement of the salivary glands. In pediatric SS, extraglandular manifestations represent a significant feature and, among these, kidney manifestations are relevant. Kidney involvement is observed in 5-20.5% of children with SS, most frequently tubulointerstitial nephritis. This injury can lead to serious phenotypes, including distal kidney tubular acidosis with the development of severe hypokalemia, which can lead to ECG abnormalities, weakness, and hypokalemic periodic paralysis. Kidney implications in pediatric SS also include nephrolithiasis, nephrocalcinosis, and various types of glomerular damage, which often require immunosuppressive therapies. Laboratory findings are usually comparable to adults, including hyperglobulinemia and high rates of antinuclear antibodies (ANA, 63.6-96.2%), and anti-Ro/SSA (36.4-84.6%). The current classification criteria for SS are inaccurate for the pediatric population, and more specific criteria are needed to improve the diagnostic rate. Due to the rarity of the disease, strong recommendations for treatment are lacking, and several therapeutic strategies have been reported, mostly based on glucocorticoids and disease-modifying antirheumatic drugs, with different outcomes. The aim of this paper is to provide an overview of the kidney implications of pediatric SS based on the latest evidence of the medical literature.

Overlap Syndrome of Diffuse Systemic Sclerosis, Sjögren Syndrome, and ANCA-Associated Renal-Limited Vasculitis: Three Entities in One Patient - Case Report

Introduction

The presence of three different entities in a single patient is usually of clinical interest and mostly anecdotal. The overlap of systemic sclerosis (SSc), Sjögren syndrome (SS), and ANCA-associated renal-limited vasculitis has been reported only once previously.

Case Presentation

A 61-year-old female was evaluated at consultation with 2 years of symptomatology, presenting cardboard-like skin, sclerodactyly, limited oral opening, and dry skin and eyes. She was admitted for progressive renal failure (serum creatinine, 5.5 mg/dL). Her serology work-up showed positive anti-SCL-70, anti-Ro, anti-La, anti-MPO, and antinuclear antibodies. Renal biopsy was performed and confirmed histological findings for SSc, SS, and ANCA-associated vasculitis with active extracapillary glomerulonephritis with fibrous predominance (EUVAS-Berden sclerotic class), active tubulointerstitial nephritis, focal tubular injury, and moderate chronic arteriolopathy. Treatment with 6 monthly doses of methylprednisolone and cyclophosphamide was established. At the last follow-up, the patient maintained a stable serum creatinine level of 2.6 mg/dL and had decreased proteinuria, no erythrocyturia, and no requirement for renal replacement therapy.

Conclusion

Systemic sclerosis is a rare autoimmune disease; nevertheless, overlap with Sjögren syndrome is relatively common, although its association with ANCA vasculitis is anecdotal. Diagnostic integration presents a challenge for nephrologists to define the prognosis and a specific treatment.

A Diagnostic and Therapeutic Dilemma Concerning Exostosin 1/Exostosin 2-associated Lupus-like Membranous Nephropathy with Positive Antinuclear Antibody in an Elderly Man with Various Immune Abnormalities

Exostosin 1 (EXT1) and exostosin 2 (EXT2)-associated membranous nephropathy (MN) may be associated with active autoimmune disease. We encountered an elderly man who presented with EXT1/EXT2-associated lupus-like MN with full house immune deposits, monoclonal gammopathy of uncertain significance and Sjögren's syndrome. The patient exhibited various other immune abnormalities. Although he did not fulfill the criteria of clinical systemic lupus erythematosus (SLE), he met a stand-alone renal criterion of the Systemic Lupus International Collaborating Clinics (SLICC) 2012. Whether or not a stand-alone renal criterion with EXT1/EXT2 positivity, as in the present patient, can efficiently guide decisions regarding the diagnosis and treatment of SLE remains a clinical dilemma.

Related factors of renal injury in primary Sjögren's syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is a common chronic systemic autoimmune disorder which primarily affects the exocrine glands. Patients may have extraglandular disease involving multiple organs, including the kidneys. This study aimed at investigating the clinical data and laboratory markers which were associated with renal function damage or renal involvement.

METHOD

One thousand two hundred eighty-eight adult pSS patients from the Department of Rheumatology and Clinical Immunology were enrolled in this retrospective cohort study. And there were 334 patients of them followed up for more than two years for analyzing demographic, clinical data and laboratory markers. Statistical analysis was performed by R software (Version 3.6.2).

RESULT

Nearly 95% of 1288 pSS patients were women, and the positive rates of anti-SSA (Sjögren's syndrome A) and anti-SSB were 63% and 27% respectively. 12% of the pSS patients presented renal involvement with eGFR < 60 mL/min/1.73 m2, and the mean age of hospital presentation, serum creatinine and urea were the highest (P < 0.001), and ANA (antinuclear antibody)-positive, anti-SSB-positive and anti-scl-70-positive were more prevalent in this group. Multivariate analyses showed that age, urea, chlorine and anti-SSA indicate a significant association with renal dysfunction. Potassium, sodium and Jo-1 were also confirmed to be related with decreased renal function. The receiver operating characteristic (ROC) analysis including the above factors showed a good performance on the evaluation of renal injury including eGFR < 60 mL/min/1.73 m2 and eGFR 60 -90 mL/min/1.73 m2 in pSS, with area under curve (AUC) values of 0.957 and 0.821, and high sensitivity (71.1% and 84.4%) and specificity (95.5% and 70.5%). After a more than two years follow-up of anti-SSA positive patients, 34.14% of them developed decreased renal function, and 13.58% of them experienced a progression of renal injury with a 23.64% decrease in eGFR.

CONCLUSION

Age, urea, chlorine, and anti-SSA were highly associated with renal injury in pSS. Early screening for autoantibodies would be meaningful for evaluation and prevention of renal injury in pSS.

Associations between neuromyelitis optica spectrum disorder, Sjögren's syndrome, and conditions with electrolyte disturbances

OBJECTIVE

Electrolyte disorders are among the important conditions negatively affecting the disease course of neuromyelitis optica spectrum disorder (NMOSD). Possible mechanisms may include renal tubular acidosis (RTA) accompanying Sjögren's syndrome (SS), syndrome of inappropriate antidiuretic hormone secretion (SIADH), and central diabetes insipidus (DI). Currently, the overlap profiles between these conditions remain uncertain.

METHODS

This cross-sectional study collected data from the nationwide administrative Diagnosis Procedure Combination (DPC) database and evaluated the overlap profiles.

RESULTS

Among the 28,285,908 individuals from 1203 DPC-covered hospitals, 8477 had NMOSD, 174108 had SS, 4977 had RTA, 7640 had SIADH, and 24,789 had central DI. Of those with NMOSD, 986 (12%) had SS. The odds ratio (OR) for a diagnosis of NMOSD in those with SS compared with those without was 21 [95% confidence interval (CI), 20-23]. Overlap between NMOSD and SS was seen both in males (OR, 28 [95% CI, 23-33]) and females (OR, 16 [15-17]) and was more prominent in the younger population. Among patients with SS, the prevalence of RTA was lower in patients with NMOSD compared with those without NMOSD. Patients with NMOSD showed a higher prevalence of SIADH (OR, 11 [7.5-17]; p < 0.0001) and DI (OR, 3.7 [2.4-5.3]; p < 0.0001). Comorbid SS in NMOSD was associated with a higher prevalence of DI.

CONCLUSIONS

Patients with NMOSD are likely to have SS, SIADH, and central DI. RTA in SS does not facilitate the overlap between NMOSD and SS. SS in NMOSD may predispose patients to DI.

Renal tubular acidosis without interstitial nephritis in Sjögren's syndrome: a case report and review of the literature

BACKGROUND

Renal tubular acidosis is the principal clinical feature associated with tubulointerstitial nephritis in patients with primary Sjögren's syndrome. Renal tubular dysfunction due to interstitial nephritis has been considered the underlying pathophysiology connecting renal tubular acidosis and primary Sjögren's syndrome. However, the detailed mechanisms underlying the pathophysiology of renal tubular acidosis in primary Sjögren's syndrome is not fully understood.

CASE PRESENTATION

A 30-year-old woman was admitted with complaints of weakness in the extremities. The patient was hospitalized thirteen years earlier for similar issues and was diagnosed with hypokalemic paralysis due to distal renal tubular acidosis with primary Sjögren's syndrome. This diagnosis was based on a positive Schirmer's test. Besides, anti-Sjögren's syndrome-related antigen A was also detected. Laboratory tests indicated distal RTA; however, a renal biopsy showed no obvious interstitial nephritis. Laboratory tests conducted during the second admission indicated distal renal tubular acidosis. Therefore, a renal biopsy was performed again, which revealed interstitial nephritis. Histological analysis of acid-base transporters revealed the absence of vacuolar type H+-ATPases in the collecting duct. The vacuolar type H+-ATPase was also absent in the past renal biopsy, suggesting that the alteration in acid-base transporters is independent of interstitial nephritis.

CONCLUSIONS

This case study demonstrates that vacuolar-type H+-ATPases are associated with distal renal tubular acidosis, and distal renal tubular acidosis precedes interstitial nephritis in patients with primary Sjögren's syndrome.

Direct infiltration of clonal plasma cells causes renal insufficiency in patients with monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a benign but precancerous condition that can progress to multiple myeloma. Patients with MGUS are typically monitored closely for signs of disease progression, but in some cases, they may also develop renal insufficiency, a condition known as monoclonal gammopathy of renal significance (MGRS). In MGRS, M-protein secreted by a nonmalignant or premalignant cell clone triggers renal damage by definition. Herein, we report a case of a 66-year-old Asian male with MGUS complicated by renal insufficiency. A kidney biopsy showed no evidence of renal injury mediated by M-protein; instead, the direct infiltration of clonal cells into renal tissues was observed. Although five similar cases have been previously reported, our case is unique in that the involvement of clonal cells was directly confirmed by fluorescence in situ hybridization. Our findings suggest the need to consider a novel disease concept, as this phenomenon appears to be reproduced.

The Spectrum of Extraglandular Manifestations in Primary Sjögren's Syndrome

Extraglandular manifestations (EGMs) in primary Sjogren's syndrome (pSS) represent the clinical expression of the systemic involvement in this disease. EGMs are characterized by a wide heterogeneity; virtually any organ or system can be affected, with various degrees of dysfunction. The existing gaps of knowledge in this complex domain of extraglandular extension in pSS need to be overcome in order to increase the diagnostic accuracy of EGMs in pSS. The timely identification of EGMs, as early as from subclinical stages, can be facilitated using highly specific biomarkers, thus preventing decompensated disease and severe complications. To date, there is no general consensus on the diagnostic criteria for the wide range of extraglandular involvement in pSS, which associates important underdiagnosing of EGMs, subsequent undertreatment and progression to severe organ dysfunction in these patients. This review article presents the most recent basic and clinical science research conducted to investigate pathogenic mechanisms leading to EGMs in pSS patients. In addition, it presents the current diagnostic and treatment recommendations and the trends for future therapeutic strategies based on personalized treatment, as well as the latest research in the field of diagnostic and prognostic biomarkers for extraglandular involvement in pSS.

A Rare Case of Nephrotic Syndrome in the Setting of Sjogren Syndrome-related Cryoglobulinemic Vasculitis

Cryoglobulinemia is a rare entity which frequently occurs in the setting of an underlying disease, with chronic hepatitis C virus infections and primary Sjogren syndrome being the most common underlying conditions. Cryoglobulinemic vasculitis (CV) is an immune-mediated type of small-vessel vasculitis with a broad spectrum of specific organ involvement, including renal, pulmonary, peripheral nerve, and cutaneous involvement and variable manifestations that can be life threatening. Moreover, a strong relationship between cryoglobulinemia and CV, with the future development of lymphoma, is well established. We present the case of a 72-year-old Caucasian male referred for nephrotic syndrome and acute renal injury. A diagnosis of Sjogren syndrome-associated CV was made, and he was successfully treated with rituximab and plasma exchange sessions.

Quadriparesis and Broad Complex Tachycardia Secondary to Severe Hypokalaemia Induced by Distal Renal Tubular Acidosis as the Initial Manifestation of Sjogren's Syndrome

Sjogren's syndrome is an autoimmune disorder characterized by lymphocytic infiltration of exocrine glands that typically manifests as dysfunction of the lacrimal or salivary glands. About one-third of Sjogren's syndrome patients exhibit systemic symptoms. In one-third of Sjogren's syndrome cases, renal tubular acidosis (RTA) is present. Hypokalemia is the most prevalent electrolyte disorder in patients with distal RTA. A middle-aged female presented to the emergency department with a complaint of sudden-onset quadriparesis followed by shortness of breath. Her arterial blood gas analysis revealed severe hypokalaemia and metabolic acidosis. ECG revealed broad complex tachycardia, which resolved after starting potassium infusion. On evaluating the cause of normal anion gap metabolic acidosis and hypokalaemia, she was found to have distal renal tubular acidosis (RTA). Furthermore, on evaluating the cause of distal RTA, her SSA/Anti Ro and SSB/Anti La levels came out to be elevated, and a probable diagnosis of Sjogren's syndrome was made. Severe hypokalaemia leading to hypokalaemia quadriparesis and broad complex tachycardia as the initial manifestation of distal RTA due to Sjogren's syndrome is uncommon. Timely recognition and prompt replacement of potassium are key to improved outcomes. It is also important to note that Sjogren's syndrome should be taken into account even in the absence of sicca symptoms, like in our case.

The pathophysiology of distal renal tubular acidosis

The kidneys have a central role in the control of acid-base homeostasis owing to bicarbonate reabsorption and production of ammonia and ammonium in the proximal tubule and active acid secretion along the collecting duct. Impaired acid excretion by the collecting duct system causes distal renal tubular acidosis (dRTA), which is characterized by the failure to acidify urine below pH 5.5. This defect originates from reduced function of acid-secretory type A intercalated cells. Inherited forms of dRTA are caused by variants in SLC4A1, ATP6V1B1, ATP6V0A4, FOXI1, WDR72 and probably in other genes that are yet to be discovered. Inheritance of dRTA follows autosomal-dominant and -recessive patterns. Acquired forms of dRTA are caused by various types of autoimmune diseases or adverse effects of some drugs. Incomplete dRTA is frequently found in patients with and without kidney stone disease. These patients fail to appropriately acidify their urine when challenged, suggesting that incomplete dRTA may represent an intermediate state in the spectrum of the ability to excrete acids. Unrecognized or insufficiently treated dRTA can cause rickets and failure to thrive in children, osteomalacia in adults, nephrolithiasis and nephrocalcinosis. Electrolyte disorders are also often present and poorly controlled dRTA can increase the risk of developing chronic kidney disease.

The role of lysosomes in metabolic and autoimmune diseases

Lysosomes are catabolic organelles that contribute to the degradation of intracellular constituents through autophagy and of extracellular components through endocytosis, phagocytosis and macropinocytosis. They also have roles in secretory mechanisms, the generation of extracellular vesicles and certain cell death pathways. These functions make lysosomes central organelles in cell homeostasis, metabolic regulation and responses to environment changes including nutrient stresses, endoplasmic reticulum stress and defects in proteostasis. Lysosomes also have important roles in inflammation, antigen presentation and the maintenance of long-lived immune cells. Their functions are tightly regulated by transcriptional modulation via TFEB and TFE3, as well as by major signalling pathways that lead to activation of mTORC1 and mTORC2, lysosome motility and fusion with other compartments. Lysosome dysfunction and alterations in autophagy processes have been identified in a wide variety of diseases, including autoimmune, metabolic and kidney diseases. Deregulation of autophagy can contribute to inflammation, and lysosomal defects in immune cells and/or kidney cells have been reported in inflammatory and autoimmune pathologies with kidney involvement. Defects in lysosomal activity have also been identified in several pathologies with disturbances in proteostasis, including autoimmune and metabolic diseases such as Parkinson disease, diabetes mellitus and lysosomal storage diseases. Targeting lysosomes is therefore a potential therapeutic strategy to regulate inflammation and metabolism in a variety of pathologies.

Novel Concepts in Nephron Sodium Transport: A Physiological and Clinical Perspective

The kidneys play a critical role in maintaining total body sodium (Na⁺) balance across a wide range of dietary intake, accomplished by a concerted effort involving multiple Na⁺ transporters along the nephron. Furthermore, nephron Na⁺ reabsorption and urinary Na⁺ excretion are closely linked to renal blood flow and glomerular filtration such that perturbations in either of them can modify Na⁺ transport along the nephron, ultimately resulting in hypertension and other Na⁺-retentive states. In this article, we provide a brief physiological overview of nephron Na⁺ transport and illustrate clinical syndromes and therapeutic agents that affect Na⁺ transporter function. We highlight recent advances in kidney Na⁺ transport, particularly the role of immune cells, lymphatics, and interstitial Na⁺ in regulating Na⁺ reabsorption, the emergence of potassium (K⁺) as a regulator of Na⁺ transport, and the evolution of the nephron to modulate Na⁺ transport.

Newly Diagnosed Sjogren Syndrome in an Elderly Patient on Dialysis: A Case Report

Sjogren syndrome (SS) is a chronic, systemic autoimmune disease that primarily affects the exocrine glands, causing dry eyes and mouth, but also presents with a variety of other symptoms. SS is a common connective tissue disease but it can be difficult to diagnose due to the non-specific symptoms and lack of diagnostic markers in many cases. This report describes a case of an elderly patient on dialysis with newly diagnosed SS. The patient had been unable to eat a normal diet for a year, but treatment had not been initiated, presumably because of his age and the fact that he was on dialysis. The patient's symptoms improved with the administration of glucocorticoids. This is a very educational case for physicians to recognize undiagnosed SS patients presenting with non-specific symptoms.

Fanconi syndrome in an elderly patient with membranous nephropathy during treatment with the immunosuppressant mizoribine

We report on an 80-year-old man diagnosed with Fanconi syndrome induced by mizoribine after 4 weeks of administration to treat membranous nephropathy. Mizoribine is an oral immunosuppressant that inhibits inosine monophosphate dehydrogenase and is widely used in Japan for the treatment of autoimmune diseases and nephrotic syndrome, as well as after renal transplantation. Acquired Fanconi syndrome is often caused by drugs (antibacterial, antiviral, anticancer, and anticonvulsant drugs) and is sometimes caused by autoimmune diseases, monoclonal light chain-associated diseases, or heavy metal poisoning. In our patient, hypokalemia, hypophosphatemia, glucosuria, hypouricemia, and severe proteinuria resolved gradually after discontinuation of mizoribine administration, despite oral administration of prednisolone followed by a single intravenous injection of rituximab. The patient was ultimately diagnosed with Fanconi syndrome induced by mizoribine based on his clinical course and his typical laboratory data with the absence of proximal tubular acidosis. To our knowledge, this is the first report of Fanconi syndrome possibly induced by mizoribine. Although the precise mechanism by which mizoribine induces proximal tubular dysfunction is unknown, we suggest that nephrologists should be aware of the onset of Fanconi syndrome, a rare complication during mizoribine treatment.

Comprehensive analysis of clinical and laboratory features of 440 published cases of Sjögren's syndrome and renal tubular acidosis

AIM

To describe the clinical and laboratory features of Sjögren's syndrome (SS) with renal tubular acidosis (RTA) from published literature.

METHODS

A systematic search of indexed publications in all languages till December 2021 identified cases of SS with RTA (SS-RTA) and were included if either antibody (anti-SSA/anti-SSB) or salivary gland histopathology were positive.

RESULTS

There were 440 cases of SS-RTA (63.9% from Asia, 95.5% women). The median (range) age was 37 (6-78) years. Only 7.7% had a previous diagnosis of SS. Oral or ocular sicca symptoms were present in 63.7%. Positive ocular tests, oral tests, anti-SSA, anti-SSB and salivary gland histopathology were reported in 256/331 (77.3%), 123/128 (96%), 382/407 (93.9%), 298/379 (78.6%), and 246/268 (91.8%), respectively. Hypokalemic paralysis (HP) was the presenting feature in 63.6%; 25% had multiple episodes of HP and 8.4% had respiratory paralysis. Type 1, type 2, combined type 1 & 2, and type 4 RTA was seen in 388, 8, 38, and 3 patients, respectively. Proximal dysfunction and RTA complications were infrequently evaluated. Fanconi syndrome, nephrogenic diabetes insipidus, proteinuria, and low estimated glomerular filtration rate were found in 45, 21, 178, and 157, respectively. Nephrocalcinosis, renal stones, and osteomalacia were reported in 92, 79, and 72, respectively. Tubulointerstitial nephritis was found in 142 out of 152 renal biopsies.

CONCLUSION

SS-RTA is an early manifestation of SS characterized by younger age and subclinical sicca symptoms. Although evaluated less frequently, oral sicca signs and salivary gland biopsy have a high positive yield. HP is the most common presentation. RTA is mostly distal; proximal dysfunction and complications were infrequently assessed.

Renal tubular acidosis and associated factors in patients with primary Sjögren's syndrome: a registry-based study

OBJECTIVES

To investigate the clinical features and factors associated with primary Sjögren's syndrome (pSS)-associated renal tubular acidosis (RTA).

METHOD

This case-control study was based on a multicenter pSS registry established by the Chinese Rheumatism Data Center. Patients with pSS, including those with RTA and those without renal involvement, between May 2016 and March 2020 were included in the analysis. Demographic, clinical, and laboratory data were also collected. Univariate and multivariate logistic regression analyses were used to identify factors that were associated with pSS-RTA.

RESULTS

This study included 257 pSS patients with RTA and 4222 patients without renal involvement. Significantly younger age at disease onset (40.1 ± 14.1 vs. 46.2 ± 13.1 years, P < 0.001), longer diagnosis interval (15.0 interquartile range [IQR] [1.0, 48.0] vs. 6.0 IQR [0, 34.0] months, P < 0.001), higher EULAR Sjögren's syndrome disease activity index (9 IQR [5, 15] vs. 3 IQR [0, 8], P < 0.001), and a higher prevalence of decreased estimated glomerular filtration rate (25.0% vs. 6.6%, P < 0.001) were observed in pSS patients with RTA than in those without renal involvement. Factors that were independently associated with pSS-RTA included age at disease onset ≤ 35 years (odds ratio [OR] 3.00, 95% confidence interval [CI] 2.27-3.97), thyroid disorders (OR 1.49, 95% CI 1.04-2.14), subjective dry mouth (OR 3.29, 95% CI 1.71-6.35), arthritis (OR 1.57, 95% CI 1.10-2.25), anti-SSB antibody positivity (OR 1.80, 95% CI 1.33-2.45), anemia (OR 1.67, 95% CI 1.26-2.21), elevated alkaline phosphatase level (OR 2.14, 95% CI 1.26-3.65), decreased albumin level (OR 1.61, 95% CI 1.00-2.60), and elevated erythrocyte sedimentation rate (OR 1.78, 95% CI 1.16-2.73).

CONCLUSIONS

Delayed diagnosis and decreased kidney function are common in pSS patients with RTA. pSS should be considered in patients with RTA, and early recognition and treatment may be useful in slowing the deterioration of renal function in patients with pSS-RTA. Key Points • pSS patients with RTA have earlier disease onset and higher disease activity than pSS patients without RTA, but the diagnosis was frequently delayed. • Decreased kidney function are common in pSS patients with RTA. • Sjögren's syndrome should be considered in young female patients with unexplained RTA, whereas RTA should be screened in pSS patients with early disease onset and elevated ALP level.

Childhood-onset primary Sjögren's syndrome in a tertiary center in China: clinical features and outcome

OBJECTIVES

To characterize the clinical features and outcomes of childhood-onset primary Sjögren's syndrome (pSS).

METHODS

Patients less than 18 years old who were diagnosed with pSS by paediatric rheumatologists were included, and all patients were applied the 2002 American-European Consensus Group (ACEG) criteria, the 2016 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria for pSS, or the 1999 proposed juvenile pSS criteria. The electronic medical records of patients with pSS from 2013 to 2020 were collected and analysed.

RESULTS

Thirty-nine patients were included. Of them, 27 (69.2%), 38 (97.4%) and 35 (89.7%) patients fulfilled the AECG criteria, ACR/EULAR criteria and proposed juvenile pSS criteria, respectively. The female:male ratio was 3.9:1. The median ages at first signs or symptoms and at diagnosis were 9.2 (4.7, 14.5) years and 10.9 (6.3, 15.0) years, respectively. The main clinical manifestations were rash or purpura (20, 51.3%), followed by fever (12, 30.8%), glandular enlargement/recurrent parotitis (10, 25.6%), and dry mouth and/or dry eyes (9, 23.1%). Twenty-eight (56.4%) patients had systemic damage, the most common of which was haematological involvement (14, 35.9%), followed by hepatic (13, 33.3%) and renal involvement (8, 20.5%). Thirty-eight (97.4%) patients underwent labial minor salivary gland biopsy, and all exhibited focal lymphocytic sialadenitis. All patients had a global ESSDAI score ≥ 1 at diagnosis, and the median total score at diagnosis was 8 (2, 31). Thirty-six (92.3%) patients were followed up for a median time of 23.6 (7.9, 79.5) months, and three patients developed systemic lupus erythematosus (SLE) at follow-up times of 13.3, 38.8 and 63.8 months.

CONCLUSIONS

The presentation of childhood-onset pSS is atypical, and extraglandular manifestations and systemic involvement are more common than in adult-onset pSS. Labial salivary gland biopsy is vital for patients with probable pSS. Some patients may develop SLE over time.

Renal involvement in Sjőgren's syndrome: predictors and impact on patient outcomes

Renal disease in primary Sjogren's Syndrome(pSS) occurs as tubulointerstitial nephritis(TIN) or glomerulonephritis(GN). Data from India on pSS are sparse and even less on nephritis.We studied the prevalence and impact of renal disease on patient outcomes. We reviewed 179 (F:M 12.7:1, age 41.7 ± 12.9 years) patients of pSS from records at a single centre from 2000 to 2020. Data on nephritis, clinical and laboratory variables were collected from baseline visit. Outcomes studied were chronic kidney disease(CKD) and death. We identified predictors of nephritis and rising creatinine on follow-up.Fifty-four (30.17%) patients had nephritis. Their mean age was 40.19 ± 13.28 years with 157.3 person-years follow-up. Vasculitis (OR 2.33, 1.02-5.3), fatigue (OR 3.29, 1.63-6.65), ANA positivity (OR 7.79, 1-60.62), anti-Ro52 (OR 2.74, 1.18-6.39), anti-La (OR 2.13, 1.1-4.14), both Ro and La (OR 2.4, 1.23-4.69) and lymphopenia (OR 2.27, 1.16-4.41) predicted nephritis on univariate analysis. On multivariate analysis, only fatigue (OR 2.83, 1.22-6.57) and an interaction between polyarthritis and vasculitis (OR 9.17, 1.15-72.96) was associated with nephritis. Creatinine at one (1.6 ± 1.17 mg/dL vs. 0.8 ± 0.2 mg/dL) and 2 years (1.62 ± 1.19 mg/dL vs. 0.8 ± 0.2 mg/dL) follow-up was higher in the nephritis group. Baseline haematuria, leukocyturia, 24 h urinary protein and thrombocytopenia were independent predictors of rising creatinine. Six patients died and 10 developed CKD. Event-free (death or CKD) survival was 89.1% at 5 years. Patients with nephritis had worse event-free survival.Our cohort had a younger age of onset of Sjogren's syndrome and a higher prevalence of nephritis than previously reported. Fatigue, polyarthritis and vasculitis at baseline predicted the development of nephritis. Nephritis was associated with a higher probability of death or CKD.

An Overview of the Dry Eye Disease in Sjögren's Syndrome Using Our Current Molecular Understanding

Sjögren's syndrome is a chronic and insidious auto-immune disease characterized by lymphocyte infiltration of exocrine glands. The patients typically present with ocular surface diseases related to dry eye and other systemic manifestations. However, due to the high prevalence of dry eye disease and the lack of objective and clinically reliable diagnostic tools, discriminating Sjögren's syndrome dry eye (SSDE) from non-Sjögren's syndrome dry eye (NSSDE) remains a challenge for clinicians. Diagnosing SS is important to improve the quality of life of patients through timely referral for systemic workups, as SS is associated with serious systemic complications such as lymphoma and other autoimmune diseases. The purpose of this article is to describe the current molecular understanding of Sjögren's syndrome and its implications for novel diagnostic modalities on the horizon. A literature review of the pre-clinical and clinical studies published between 2016 and 2022 was conducted. The SSDE pathophysiology and immunology pathways have become better understood in recent years. Novel diagnostic modalities, such as tear and saliva proteomics as well as exosomal biomarkers, provide hope on the horizon.

Recurrent Hyponatremia in the Setting of Autoimmune Disease with Sicca Syndrome: A Case Report

Sjogren's syndrome is an autoimmune disease associated with xerostomia and xerophthalmia. The association of Sjogren's with hyponatremia has rarely been reported and has been attributed to syndrome of inappropriate antidiuretic hormone secretion. Here, we report a case of polydipsia secondary to xerostomia as a cause of chronic hyponatremia in the setting of Sjogren's syndrome. Analysis of the patient's medical record, including medication reconciliation and dietary habits, revealed several underlying causes of her recurrent hyponatremia. A thorough review of the patient's clinical history and good bedside examination may reduce prolonged hospitalizations and improve the quality of life of a hyponatremic population of patients who are predominantly elderly.

[Renal manifestations in connective tissue diseases]

Connective tissue diseases (CTD) comprise a group of inflammatory systemic diseases that can affect various organs. Kidney involvement is frequently associated with significant irreversible damage and often before patients become symptomatic. Screening tests of blood and urine as well as clinical vigilance are therefore essential for all CTDs with possible renal involvement. A kidney biopsy is the gold standard for the diagnosis, prognosis and treatment decisions. A common and severe organ involvement in systemic lupus erythematosus (SLE) is glomerulonephritis (GN), also collectively referred to as lupus nephritis (LN). If left untreated LN often leads to end-stage renal failure. The treatment depends on the clinical parameters and histopathology of the renal involvement. Mycophenolate mofetil and cyclophosphamide are potent but nonspecific immunosuppressants which have been available for many years. Recently, new substances specific for LN have also been approved for the first time. Kidney involvement in Sjogren's syndrome has been far less studied. In studies the frequency of renal involvement is still unclear and ranges from 5% to 33%. Tubulointerstitial nephritis (IN) is the typical form of renal involvement which clearly differs from GN in its clinical presentation. Recommendations for treatment are based exclusively on retrospective studies. A renal crisis in systemic scleroderma (SSc) is a rare but feared complication with a high mortality. An antiphospholipid syndrome (APS) nephropathy (APSN) can occur during CTD. These entities are vasculopathies and often thrombotic microangiopathies, which clearly differ from GN and IN in terms of pathophysiology, clinical features and treatment. This article provides an overview of the diversity of the most important renal manifestations of CTDs.

Tubulointerstitial nephritis with IgA kappa-positive plasma cells in a patient with primary Sjögren’s syndrome and monoclonal gammopathy

This is a case report of a 69-year-old Japanese man who has been undergoing treatment for primary Sjögren's syndrome (pSS) since he was 62 years. A renal biopsy, which revealed diffuse and severe mononuclear cell infiltration in the tubulointerstitium, was performed because of progressive renal dysfunction. Immunostaining demonstrated most of the infiltrating cells to be IgA, kappa, CD38, and CD138 positive. Immunofixation blood test revealed IgA kappa-type M protein; however, bone marrow abnormalities or lymph node enlargements on examination or imaging, respectively, were not observed. Tubulointerstitial nephritis caused by monotypic plasmacytic infiltration in pSS, accompanied with a monoclonal gammopathy of undetermined significance (MGUS), was diagnosed. A treatment of prednisolone 40 mg/day was initiated, promptly improving the patient's serum creatinine levels from 3.0 to 1.5 mg/dl. The infiltrating cells in pSS-associated tubulointerstitial nephritis are generally polytypic plasmacytes and lymphocytes, but in the present case, monotypic plasmacytes were predominant. This case is remarkable and rare and can be considered a complication of pSS or MGUS. Since it may become a new disease entity, it is important to accumulate similar cases.

Exposure to ambient gaseous pollutant and daily hospitalizations for Sjögren's syndrome in Hefei: A time-series study

OBJECTIVE

Increasing evidence suggested that gaseous pollutants were associated with the development of autoimmune diseases, while there were few studies on the association between gaseous pollutants and Sjögren's syndrome (SS). This study sought to assess the relationship between exposure to several gaseous pollutants and the hospitalizations for SS.

METHODS

The data regarding SS hospitalizations, gaseous pollutants, and meteorological factors in Hefei from 2016 to 2021 were collected. A distributed lag non-linear model combined with a generalized linear model were adopted to analyze the association between gaseous pollutants and SS hospitalizations, and stratified analyses were also conducted.

RESULTS

We detected significant associations between gaseous pollutants (NO2, SO2, O3, CO) and SS hospitalizations. Exposure to NO2 was linked with the elevated risk of hospitalizations for SS (RR=1.026, lag1 day). A positive correlation between CO exposure and hospitalizations for SS was found (RR=1.144, lag2 day). In contrast, exposure to SO2, O3 was respectively related to the decreased risk of hospitalizations for SS (SO2: RR=0.897, lag14 day; O3: RR=0.992, lag9 day). Stratified analyses found that female patients were more vulnerable to these gaseous pollutants. SS patients ≥ 65 years were more susceptible to NO2, CO exposure, and younger patients were more vulnerable to O3 exposure. In addition, exposure to O3, CO in cold season were more likely to affect hospitalizations for SS.

CONCLUSION

Our results demonstrated a significant association between exposure to NO2, CO and elevated risk of hospitalizations for SS, and SO2, O3 exposure might be linked to reduced risk of SS hospitalizations.

Heavy Chain/Light Chain Antibody Immunofluorescence to Identify Monoclonal Plasma Cells in a Case of Plasma Cell-Rich Acute Interstitial Nephritis

Heavy/light chain (HLC) antibodies can be used to quantify intact HLC pairs. In immunofluorescence studies, they allow differentiation of monoclonal versus polyclonal immunoglobulin deposits in kidney diseases that occur in the setting of monoclonal gammopathy. Here, we present a case of a patient with acute kidney injury with first kidney biopsy suggestive of acute interstitial nephritis with a polymorphous infiltrate of plasma cells. Routine immunofluorescence did not show a monotypic plasma cell infiltrate. Serum protein electrophoresis and immunofixation revealed monoclonal immunoglobulin A (IgA) lambda. She improved with steroid therapy, but kidney function worsened after steroids were stopped. She underwent a second kidney biopsy, which showed plasma cell-rich interstitial infiltrate with a population of IgA lambda-restricted plasma cells on routine immunofluorescence. In light of this finding, Hevylite HLC antibody was used to reassess the first biopsy, which confirmed the presence of a population of plasma cells with IgA lambda restriction. Because of the presence of monotypic plasma cells, anti-CD38 monoclonal antibody (daratumumab) was initiated.

TAFRO syndrome: A severe manifestation of Sjogren's syndrome? A systematic review

BACKGROUND

Sjögren's syndrome (SjS) is a systemic autoimmune disease characterized by lymphocytic infiltration of the salivary and lacrimal glands associated with sicca syndrome. TAFRO syndrome is a systemic inflammatory disease of unknown cause, characterized by Thrombocytopenia, Anasarca, Fever, Reticulin fibrosis, Renal dysfunction and Organomegaly, first reported in 2010 in Japanese patients. Despite their rarity, both conditions have been concurrently reported in several patients during the recent years, hence questioning the existence of shared or related features.

METHODS

A systematic review of the literature regarding SjS associated with TAFRO syndrome (SjS-TAFRO) was performed. The 2019 updated Masaki diagnostic criteria were used for TAFRO syndrome and SjS was considered when the diagnosis was mentioned by the authors, necessarily with either anti-Sjogren's Syndrome A (SSA) ± anti-Sjogren's Syndrome B (SSB) antibodies and/or histological evidence of focal lymphocytic sialadenitis.

RESULTS

Ten cases of SjS-TAFRO have been reported in the literature to date. Compared to SjS patients without TAFRO syndrome, these 10 SjS-TAFRO had a lower female predominance (2.3:1 vs 9:1 women to man ratio) and a higher frequency of anti-SSA antibodies (90% vs 70%). All fulfilled the three major Masaki criteria i.e., anasarca, thrombocytopenia, and systemic inflammation. Seven of them (70%) had megakaryocyte hyperplasia or reticulin fibrosis in the bone marrow. Lymph node biopsy was performed in 8 out of 10 cases (80%) and results were consistent with Castleman disease in 6 (75%). Eight of them had developed renal failure (80%) within six months. Nine of them (90%) had organomegaly, with hepatosplenomegaly in 8 cases and splenomegaly alone in 1.

CONCLUSION

This review brings new insights regarding TAFRO syndrome and suggests it could be a severe manifestation of SjS. The identification of shared abnormal signaling pathways could help in the therapeutic management of both diseases, which face an unmet therapeutic need.

Renal Involvement in Primary Sjogren's Syndrome: A Case Series of Three Cases with Various Clinicopathological Presentations

Sjogren's syndrome is a prevalent and underdiagnosed systemic disease that primarily affects epithelial tissue. It may affect renal function, either as an epithelial disease causing tubulointerstitial nephritis (TIN) or as an immune complex-mediated glomerulopathy. These lesions may cause a variety of clinical features, both overt and occult. The epithelial disease is mediated by B and T cells. The prevalence of renal involvement in primary Sjogren's syndrome has been reported to range approximately from 10% to 30%. Patients with renal involvement in primary Sjogren's syndrome may have renal manifestations, such as renal tubular acidosis (RTA) Type I, TIN, diabetes insipidus, nephrolithiasis, and Fanconi syndrome. Distal RTA was reported more commonly than proximal RTA, which can present as acute hypokalemic paralysis. We present three cases of primary Sjogren's syndrome with significant renal involvement and various clinicopathological presentations.

Renal involvement of lymphomas proven by kidney biopsy: report of 10 cases from a tertiary care center and comparison with the literature

Lymphomas localized in the kidney are a rare entity that may be challenging to diagnose. We analyzed data from 10 patients with renal involvement of lymphoma diagnosed between 2009 and 2019 on fine needle biopsy from our tertiary center, and compared these with findings of 160 cases reported in the literature. Diffuse large B-cell lymphoma was the main histology subtype (40 and 38% in our sample and in the literature, respectively), followed by low-grade B-cell lymphomas, mostly from the marginal zone (MZ). Altogether, 106 patients had urological inaugural symptoms and 64 had general symptoms. Patients with urological presentation more often had renal masses than diffuse infiltration (p < 0.001), unilateral tumors (p = 0.0036) and low-grade B-cell lymphomas (17 vs 6%, p = 0.043). In both groups, nearly one-fourth of patients had diffuse (stage IV) lymphomas. Overall survival did not differ by the presence of urological/systemic symptoms, stage or aggressive lymphoma status. Notably, 3 of 10 patients from our series had MZ lymphomas associated with primary Sjögren syndrome revealed by acute kidney injury, including one where the autoimmune disease was detected. Lymphoproliferative disorders localized in the kidney are a challenging condition that can lead to detection of aggressive or diffuse lymphomas.

Virus Infections Play Crucial Roles in the Pathogenesis of Sjögren’s Syndrome

Sjögren’s syndrome (SS) is an autoimmune disease especially targeting exocrine glands, such as the salivary and lacrimal glands. A radical therapy for SS based on its etiology has not been established because of the complex pathogenesis of the disease. Several studies have demonstrated a relationship between virus infection and SS pathogenesis. In particular, infection with the Epstein-Barr (EB) virus among others is a potent factor associated with the onset or development of SS. Specifically, virus infection in the target organs of SS triggers or promotes autoreactive responses involving the process of autoantigen formation, antigen-presenting function, or T-cell response. Our review of recent research highlights the crucial roles of virus infection in the pathogenesis of SS and discusses the critical association between virus infection and the etiology of autoimmunity in SS.

TIGIT as a Promising Therapeutic Target in Autoimmune Diseases

Co-inhibitory receptors (IRs) are molecules that protect host against autoimmune reactions and maintain peripheral self-tolerance, playing an essential role in maintaining immune homeostasis. In view of the substantial clinical progresses of negative immune checkpoint blockade in cancer treatment, the role of IRs in autoimmune diseases is also obvious. Several advances highlighted the substantial impacts of T cell immunoglobulin and ITIM domain (TIGIT), a novel IR, in autoimmunity. Blockade of TIGIT pathway exacerbates multiple autoimmune diseases, whereas enhancement of TIGIT function has been shown to alleviate autoimmune settings in mice. These data suggested that TIGIT pathway can be manipulated to achieve durable tolerance to treat autoimmune disorders. In this review, we provide an overview of characteristics of TIGIT and its role in autoimmunity. We then discuss recent approaches and future directions to leverage our knowledge of TIGIT as therapeutic target in autoimmune diseases.

Recommendations for evaluation and diagnosis of extra-glandular manifestations of primary sjogren syndrome: results of an epidemiologic systematic review/meta-analysis and a consensus guideline from the Brazilian Society of Rheumatology (articular, pulmonary and renal)

Sjogren's Syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration of the exocrine glands and other organs, associated with sicca syndrome but also with systemic involvement with varying degrees of severity. Despite their importance, these systemic manifestations are not routinely evaluated and there is no homogenous approach to their diagnosis or evaluation. To close this gap, a panel of experts from the Brazilian Society of Rheumatology conducted a systematic review and meta-analysis on the identification of epidemiologic and clinical features of these manifestations and made recommendations based on the findings. Agreement between the experts was achieved using the Delphi method. The first part of this guideline summarizes the most important topics, and 11 recommendations are provided for the articular, pulmonary, and renal care of SS patients.

Kidney Stones, Proteinuria and Renal Tubular Metabolic Acidosis: What Is the Link?

Kidney stone disease represents a rare cause of chronic kidney disease (2−3%) but has severe clinical consequences. Type 1 renal tubular acidosis is a strong lithogenic condition mainly related to primary Sjögren syndrome. This study aimed to illustrate an unusual presentation of Sjögren syndrome to improve the knowledge about rare kidney stone diseases, and to provide clues for the diagnostic approach in this specific condition. We report the case of a 35-year-old Indian woman with severe nephrocalcinosis and chronic kidney disease with tubular proteinuria who presented for metabolic assessment. We found advanced chronic kidney disease, low serum bicarbonate, permanent alkaline urine with pH at ~7.1, and severe hypocitraturia corresponding to type 1 renal tubular acidosis. The erythrocyte sedimentation rate was high. Serological screening for HAV, HBV, HCV, HIV, EBV was negative and complement was normal. Autoimmune screening showed antinuclear antibodies (>1/1.280) with anti-SSA, anti-SSA/Ro52 and anti-SSB antibodies. Genetic testing excluded an inherited cause of renal tubular acidosis. A renal biopsy showed moderate chronic tubulo-interstitial nephritis without any glomerular involvement. Primary Sjögren syndrome with significant renal involvement was considered, and corticosteroids were then subsequently initiated in combination with potassium citrate with vitamin D substitution. Only partial improvement was observed in electrolytes disturbance. After 15 months, her renal function remained stable. In conclusion, nephrocalcinosis could be the first manifestation of severely impacting diseases such as primary Sjögren syndrome. Chronic kidney disease, bilateral nephrocalcinosis, and metabolic acidosis can be linked through type 1 renal tubular acidosis. Therefore, autoimmune screening for Sjögren syndrome should be considered in such cases.

A case of smoldering antineutrophil cytoplasmic antibody-associated vasculitis development during the course of primary Sjögren's syndrome

Various forms of glomerular lesions have been described in primary Sjögren's syndrome (pSjS); however, myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is rarely reported, and the disease onset and clinical course of ANCA-associated vasculitis (AAV) complicated by pSjS are not well understood. A 51-year-old woman was referred to our hospital because of mild proteinuria and microscopic hematuria. She fulfilled the classification criteria for pSjS. We performed a kidney biopsy; however, it revealed no characteristic findings for pSjS, vasculitis, or other autoimmune diseases, including systemic lupus erythematosus. After 9 months, urinalysis abnormalities worsened and renal function was slowly declining, and ANCA was found to be positive. A second kidney biopsy was performed, revealing MPO-ANCA-associated pauci-immune segmental necrotizing glomerulonephritis with crescent formation. Even though immunofluorescence microscopy did not reveal any positive findings, additional electron microscopy demonstrated the presence of mesangial electron-dense deposits in both kidney biopsies. Based on kidney biopsy results and sequential serum ANCA measurements, we considered that smoldering ANCA-associated vasculitis had developed in this patient as this can develop during the clinical course of pSjS. She responded well to steroid therapy. Serum measurement, especially perinuclear, ANCA levels can be useful in patients with pSjS to detect the onset of ANCA-associated vasculitis, even in the absence of acute renal deterioration or severe urinary abnormalities.

Sjögren syndrome overlapping with ANCA-associated vasculitis: Four additional cases and systematic literature review

OBJECTIVES

Sjögren's syndrome (SS) and ANCA-associated vasculitis (AAV) have distinct clinical presentation and evolution, with paucity of reports on overlap syndrome. We aimed to better characterize this entity.

METHODS

We report four additional cases from the Montpellier university hospital. We also performed a systematic literature review, according to PRISMA guidelines, in Medline, Embase, Web of science, Cochrane Library, and grey literature. Demographic, clinical, and paraclinical data on SS and AAV were analysed.

RESULTS

A total of 3133 articles was identified in databases, with 2695 articles screened for eligibility. After exclusion, we had 30 articles on 40 patients to analyse, in addition to 4 patients from our local recruitment (44 patients overall). Patients were female in 81.8%, with median age at AAV onset of 63.5 years. All patients but one presented with SS before, or concomitantly to the diagnosis of AAV, with a median delay of 12 months between both diagnoses. AAV predominantly had renal involvement (35/44 patients, 79.5%), anti-MPO antibodies being the most frequent (35 patients), even in patients presenting with granulomatosis with polyangiitis. We observed significantly more Raynaud phenomenon and associated auto-immune diseases in the group of non-granulomatous AAV (10 patients versus 1, p = 0.015 and 8 patients versus 0, p = 0.013, respectively).

CONCLUSIONS

This is the largest descriptive study on the association between SS and AAV, providing information on this challenging diagnosis and interplay between these two diseases. Particular attention should be paid in the first months after diagnosis, given the specific complications and outcomes of each disease.

Updates in childhood Sjogren's syndrome

PURPOSE OF REVIEW

Childhood Sjogren's syndrome (cSS) is a rare, chronic autoimmune disease characterized by inflammation of the exocrine glands. cSS is underrecognized because of differences in clinical presentation compared with adults. Until recently, publications describing clinical manifestations in cSS were limited to case reports and case series with small numbers of patients. Diagnostic studies to assess glandular symptoms in adults, are less commonly obtained in children.

RECENT FINDINGS

Recent cohort studies describe presenting diagnostic clinical features in large populations of cSS and demonstrate how current classification criteria, used in adults, are not applicable to children. Recurrent parotitis is the consistent predominant manifestation that is inversely correlated with age. Novel salivary biomarkers and salivary gland ultrasonography are important objective measure, which may improve diagnosis and disease monitoring. Standardized treatment recommendations are needed.

SUMMARY

Findings from large cohort studies provide a framework for the future development of diagnostic criteria for cSS. Such criteria should incorporate objective measures that are easily obtained in children. Future research to improve understanding of the application of novel biomarkers and imaging and developing consensus on treatment recommendations is needed.

Dry eye in Sjögren's syndrome - characteristics and therapy

BACKGROUND

Sjögren's syndrome is an autoimmune disease, and its important feature is the lymphocyte infiltration of exocrine glands, including lacrimal glands. It contributes to defects of their activity and causes that one of the main manifestation of Sjögren's syndrome is dry eye. Unfortunately, the discrimination between dry eye related and non-related to Sjögren's syndrome is difficult at the initial stages of diseases. In addition, the available agents for the treatment of Sjögren's syndrome-related dry eye have limited efficacy.

AIM

The purpose of this study was to describe and emphasize differences between Sjögren's Syndrome-related dry eye and non-Sjögren's Syndrome-related dry eye together with the determination of novel therapeutic options for Sjögren's Syndrome-related dry eye.

METHOD

A review of the relevant papers describing characteristics of Sjögren's Syndrome-related dry eye and its therapy was conducted. This article is based on both pre-clinical and clinical evidences.

RESULTS

On the basis of our analysis, we indicated differences between Sjögren's Syndrome-related dry eye and non-Sjögren's Syndrome-related dry eye. Moreover, there are some novel markers that could be used in the diagnosis of Sjögren's Syndrome-related dry eye. In addition, expect artificial tear, other agents e.g. hydroxychloroquine can be effective in therapy of disease.

CONCLUSIONS

Sjögren's Syndrome-related dry eye is a disorder, whose diagnosis may be difficult and mistaken for non-Sjögren's Syndrome-related dry eye. However, Sjögren's Syndrome-related dry eye has some specific features. In addition, the development of newer and safer therapeutic agents for Sjögren's syndrome-related dry eye is needed, and therefore further clinical, randomized studies are necessary.

OUP accepted manuscript

Podocytopathies are glomerular disorders in which podocyte injury drives proteinuria and progressive kidney disease. They encompass a broad spectrum of aetiologies, resulting in pathological pictures of minimal-changes, focal segmental glomerulosclerosis, diffuse mesangial sclerosis or collapsing glomerulopathy. Despite improvement in classifying podocytopathies as a distinct group of disorders, the histological definition fails to capture the relevant biological heterogeneity underlying each case, manifesting as extensive variability in disease progression and response to therapies. Increasing evidence suggests that podocytopathies can result from a single causative factor or a combination of multiple genetic and/or environmental risk factors with different relative contributions, identifying complex physiopathological mechanisms. Consequently, the diagnosis can still be challenging. In recent years, significant advances in genetic, microscopy and biological techniques revolutionized our understanding of the molecular mechanisms underlying podocytopathies, pushing nephrologists to integrate innovative information with more conventional data obtained from kidney biopsy in the diagnostic workflow. In this review, we will summarize current approaches in the diagnosis of podocytopathies, focusing on strategies aimed at elucidating the aetiology underlying the histological picture. We will provide several examples of an integrative view of traditional concepts and new data in patients with suspected podocytopathies, along with a perspective on how a reclassification could help to improve not only diagnostic pathways and therapeutic strategies, but also the management of disease recurrence after kidney transplantation. In the future, the advantages of precision medicine will probably allow diagnostic trajectories to be increasingly focused, maximizing therapeutic results and long-term prognosis.

Clinical picture, outcome, and predictive factors of lymphoma in primary Sjogren's syndrome. Results from a harmonized dataset (1981-2021)

OBJECTIVES

Primary Sjögren's Syndrome (pSS) carries the highest risk for non-Hodgkin's lymphoma (NHL) development among systemic autoimmune diseases. However, the paucity of data on the long-term survival of those patients and the lack of established predictors for each lymphoma histologic subtype prompted our present study.

METHODS

We retrospectively analyzed 121 patients diagnosed with NHL according to the WHO classification criteria. All patients fulfilled the 2016 ACR-EULAR classification criteria for pSS. Cumulative clinical, laboratory, radiologic, treatment regimens and histologic data were recorded, harmonized, and analyzed. Overall survival (OS) and event free survival (EFS) curves were calculated. A Mucosa Associated Lymphoid Tissue lymphoma (MALTL) prediction model was developed by applying innovative data driven analysis of clinical features present at the time of pSS diagnosis.

RESULTS

MALTLs constituted the majority of lymphomas (92/121, 76,0%) followed by Diffuse Large B Cell Lymphomas (DLBCL) (11/121, 9.0%) and Nodal Marginal Zone Lymphomas (NMZL) (8/121, 7%). MALTLs show salivary glands localization, limited disease and often bone marrow and nodal involvement. The 10-year OS and EFS rates were 79% and 45,5% for MALTLs, 40,9% and 24,2% for DLBCL and 46% and 31% for NMZL. Cryoglobulinemia, focus score and the total EULAR SS Disease Activity Index (ESSDAI) composite index at pSS diagnosis were proven independent MALTL predictors. Even though MALTLs have a comparatively good survival outlook, they are accompanied by frequent events throughout their clinical course.

CONCLUSIONS

Common features of pSS, present at diagnosis, can predict future lymphomagenesis meriting a more intensive follow up plan.