Renal involvement in primary Sjögren's syndrome: A retrospective study of 103 biopsy-proven cases from a single center in China

Development of a nomogram for membranous nephropathy prediction in patients with primary Sjögren's syndrome: a 6-year retrospective study

Objectives

Nephritis is a life-threatening complication of primary Sjögren's syndrome (pSS), with membranous nephropathy (MN) being prevalent. Renal biopsy is the gold standard for MN diagnosis, but it is invasive and cannot be repeatedly performed. This study aimed to develop a nomogram for the prediction of MN in patients with pSS.

Methods

This retrospective study included patients with pSS admitted to the Rheumatology and Immunology Department of the First Affiliated Hospital of China Medical University between January 2015 and January 2021. A nomogram was developed using multivariable logistic regression analysis and evaluated using receiver operating characteristic (ROC) curve analysis. Bootstrap resampling analysis (1,000 times) was performed to evaluate the nomogram for discrimination and the calibration curve for consistency.

Results

A total of 237 patients with pSS [aged 53.00 (44.00, 61.00) years] were included, with 35 pSS-MN patients. Based on clinical practice and multivariable logistic regression analysis, seven variables associated with pSS-MN were selected, including white blood cells, creatine, complement 3, rheumatoid factor, antinuclear antibodies, anti-SSA antibody, and interstitial lung disease. The area under the ROC curve was 0.860 (95% confidence interval: 0.796-0.919), indicating good predictive power. In addition, the nomogram exhibited excellent performance, as demonstrated by the calibration curve and decision curve analysis.

Conclusion

This study developed a risk prediction nomogram for MN in patients with pSS, with high predictive power. It may be used to improve the management of patients with pSS.

Nephrolithiasis and/or nephrocalcinosis is significantly related to renal dysfunction in patients with primary Sjögren's syndrome

OBJECTIVE

The present study compared the clinical features of patients with primary Sjögren's syndrome (pSS) with and without nephrolithiasis and/or nephrocalcinosis to determine factors related to renal dysfunction.

METHODS

The clinical features of 68 patients with anti-Sjogren's syndrome antigen A (SSA)/Ro-antibody-positive pSS with and without nephrolithiasis and/or nephrocalcinosis who underwent abdominal computed tomography and/or ultrasonography were retrospectively analysed.

RESULTS

Of the 68 patients with anti-SSA-antibody-positive pSS, 23 (33%) had renal nephrolithiasis and/or nephrocalcinosis, whereas 45 (67%) did not. Fourteen (20%) patients had renal dysfunction at diagnostic imaging. Among five patients who underwent renal biopsy, four patients with renal nephrolithiasis and/or nephrocalcinosis were diagnosed with tubulointerstitial nephritis, and one without nephrolithiasis and/or nephrocalcinosis was diagnosed with minimal change nephrotic syndrome. Estimated glomerular filtration rate at diagnostic imaging was significantly lower in patients with than without nephrolithiasis and/or nephrocalcinosis group (P = 0.010). In addition to nephrolithiasis and/or nephrocalcinosis (odds ratio [OR], 3.467; P = 0.045), the gap between serum sodium and chloride concentrations (OR, 10.400; P = 0.012) and increased urinary β2-microglobulin (OR, 5.444; P = 0.033) were associated with renal dysfunction at the time of diagnostic imaging.

CONCLUSION

Nephrolithiasis and/or nephrocalcinosis, normal anion gap metabolic acidosis, and tubulointerstitial damage are associated with renal dysfunction in patients with pSS.

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.

BMSC reduces ROS and inflammation levels by inhibiting TLR4/MYD88/NF-κB signaling axis to alleviate dry eye

Objective To investigate the therapeutic effect of Bone marrow mesenchymal stem cells (BMSCs) on dry eye mice, and to investigate the mechanism of TLR4/MYD88/NF-κB signaling pathway on corneal injury repair in dry eye mice. Methods To establish a hypertonic dry eye cell model. Western blot for measureing the protein expressions of caspase-1, IL-1β，NLRP3 and ASC，and Rt-qpcr for mRNA expression. Flow cytometry for detecting the ROS content and apoptosis rate. CCK-8 for detecting the proliferation activity of cells, and ELISA for the levels of inflammation-related factors.The levels of inflammation-related factors were detected by ELISA. The dry eye mouse model of benzalkonium chloride was established. Three clinical parameters used to evaluate ocular surface damage, namely tear secretion, tear film rupture time and corneal sodium fluorescein staining, were measured with phenol cotton thread. Flow cytometry and TUNEL staining are both for he apoptosis rate. Western blot also for detecting the protein expressions of TLR4, MYD88, NF-κB, inflammation-related factors and apoptosis-related factors . The pathological changes were evaluated by HE and PAS staining. Results In vitro, BMSCs and inhibitors of TLR4, MYD88 and NF-κB showed decreased ROS content, decreased inflammatory factor protein level, decreased apoptotic protein level and increased mRNA expression compared with NaCl group. BMSCS partially reversed cell apoptosis induced by NaCl and improved cell proliferation. In vivo, it reduces corneal epithelial defects, goblet cell loss and inflammatory cytokine production, and increases tear production. In vitro, BMSC and inhibitors of TLR4, MYD88 and NF-κB could protect mice from apoptosis induced by hypertonic stress. In terms of mechanism, NACL-induced NLRP3 inflammasome formation, caspase-1 activation and IL-1β maturation can be inhibited. Conclusion BMSCs treatment can reduce ROS and inflammation levels and alleviate dry eye by inhibiting TLR4/MYD88/NF-κBsignaling pathway.

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.

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.

Serum-negative Sjogren's syndrome with minimal lesion nephropathy as the initial presentation: A case report

BACKGROUND

Primary Sjogren's syndrome (pSS) is an autoimmune disease, and renal involvement has been considered to be one of the systemic complications of pSS. Patients who have sjogren's syndrome with renal disease as the first manifestation and no exocrine gland involvement or autoantibodies can be missed clinically.

CASE SUMMARY

We here in report an unusual case of a primary Sjogren's syndrome in a 43-year-old female who had minimal lesion nephropathy as the initial presentation, and the patient was negative for serum anti-SSA and anti-SSB antibodies and did not have signs of exocrine gland involvement. The patient’s Sjogren's syndrome was confirmed by a minor salivary gland biopsy (MSGB) and a filter paper test. the patient’s oedema subsided, and the patient’s urinary protein resolved, showing that the treatment was effective.

CONCLUSION

MSGB should be considered if pSS is suspected in patients who do not have the typical pSS symptoms or who are positive for the specific autoantibodies.

Hypocomplementemia in primary Sjogren’s syndrome: association with serological, clinical features, and outcome

Objective

The aim of the present study was to assess the clinical characteristic of hypocomplementemia (HC) in primary Sjogren’s syndrome (pSS), and to address possible risk factors and the prognosis associated with HC in pSS patients.

Methods

pSS patients with HC in Hebei General Hospital from September 2016 to March 2019 were retrospectively analyzed and compared to those with normocomplementemia (NC). Logistic regression analysis was used to detect risk factors.

Results

Of the 333 patients with pSS, 84 patients (25.23%) were presented with HC at diagnosis. The presence of hyper-IgG and anti-Ro52 antibodies was significantly more common in patients with HC. In addition to systemic involvement, pSS patients with HC had more hematological, renal, and nervous system involvement, and received more immunosuppressant treatments than NC group (p < 0.05). ESSDAI score was significantly higher in patients with HC (p < 0.05). Multivariate logistic analysis indicated that leukopenia (OR = 2.23) and hyper-IgG (OR = 2.13) were independent risk factors for pSS with HC. In addition, profound CD16/CD56+ NK-cell lymphopenia was found in pSS-HC patients. More pSS patients developed SLE in the HC group than NC group (4.76% vs. 0.80%, p = 0.04) during the follow-up.

Conclusion

HC was not an uncommon manifestation of pSS and had an independent association with the main clinical and immunological features. Patients with pSS-HC had an increased possibility to develop SLE that required more positive treatment with glucocorticoids and immunosuppressants.

Key Points:

• Hypocomplementemia had an independent association with the main clinical and immunological features in primary Sjogren’s syndrome patients.

• ESSDAI score was significantly higher in patients with hypocomplementemia.

• The pSS patients with hypocomplementemia had an increased possibility to develop SLE.

Sjögren's syndrome complicated with membranous nephropathy, a cause or coincidence?

BACKGROUND

Sjögren's syndrome (SS) has been a well-documented cause of secondary membranous nephropathy (MN); however, the prevalence is quite low. Since primary MN is also a common disease in middle age, whether MN is secondary to SS or just coincidence remains uncertain. The detection of phospholipase A2 receptor (PLA2R), which is most often positive in idiopathic MN, has been rarely reported in such cases.

METHODS

We retrospectively studied 13 cases diagnosed with MN and SS in Huashan Hospital between 2009 and 2020, and performed PLA2R detection. We also review the literature by searching in the PubMed database.

RESULTS

Among the 13 patients, 8 were found to be PLA2R-positive and 5 were negative. Nine patients were female. All but 1 patients had normal renal function at the time of biopsy. All patients showed positive anti-nuclear antibody and anti-SSA. Two of the 8 PLA2R-positive patients showed positive anti-SSB and 1/8 had mild hypocomplementemia, while all 5 PLA2R-negative patients had positive anti-SSB and 3 showed hypocomplementemia. Renal biopsy revealed focal MN and markedly mesangial hyperplasia in PLA2R-negative patients. Mesangial electron deposits were observed in 1 PLA2R-positive patient in small amounts, and in 3 PLA2R-negative patients with 2 in large amounts. During follow-up, 2 patients in the PLA2R-negative group presented with progressively decreasing serum complement levels, and another one was diagnosed with systemic lupus erythematosus (SLE).

CONCLUSIONS

In patients with both MN and SS, PLA2R-negative MN should be considered as a secondary form. Careful screen for SLE is necessary in these patients during follow-up.

Factors Associated With Renal Involvement in Primary Sjögren's Syndrome: A Meta-Analysis

Background: Renal impairment is a critical complication in primary Sjögren's syndrome (pSS), resulting in chronic renal disease and even death. This meta-analysis was designed to find out the relevant factors of renal involvement in pSS.

Methods: PubMed, EMBASE, Cochrane Library, Scopus, and Web of Science were systemically searched until August 30, 2019. Studies were selected according to inclusion criteria, and data was extracted by two researchers independently. The Newcastle-Ottawa Scale was applied for quality assessment. Random- and fixed-effects models were used in this meta-analysis based on the result of the heterogeneity test. Meanwhile, a sensitivity analysis was conducted to investigate the cause of heterogeneity. Publication bias was shown in the funnel plot and evaluated further by Begg's and Egger's tests.

Results: Of the 9,989 articles identified, five articles enrolling 1,867 pSS patients were included in the final analysis, 533 with and 1,334 without renal involvement. There was no statistical significance in age and gender between these two groups. According to the meta-analysis, anti-SSB antibody, and arthralgia showed a significant association with renal involvement in pSS, the overall odds ratio (OR) values of which were 1.51 (95% CI, 1.16–1.95) and 0.59 (95% CI, 0.46–0.74), respectively. On the other hand, the overall OR values of anti-SSA antibody, rheumatoid factor, dry eyes, and labial salivary gland biopsy were just 0.90 (95% CI, 0.49–1.64), 1.05 (95% CI, 0.59–1.86), 0.60 (95% CI, 0.34–1.06), and 1.38 (95% CI, 0.98–1.95), respectively.

Conclusion: The presence of anti-SSB antibody is positively associated with renal involvement in pSS, while arthralgia is inversely associated. Large-scale prospective cohort studies are needed in the future to identify further risk factors.

Secondary Membranous Nephropathy. A Narrative Review

Membranous nephropathy (MN) is a common cause of proteinuria and nephrotic syndrome all over the world. It can be subdivided into primary and secondary forms. Primary form is an autoimmune disease clinically characterized by nephrotic syndrome and slow progression. It accounts for ~70% cases of MN. In the remaining cases MN may be secondary to well-defined causes, including infections, drugs, cancer, or autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), urticarial vasculitis, sarcoidosis, thyroiditis, Sjogren syndrome, systemic sclerosis, or ankylosing spondylitis. The clinical presentation is similar in primary and secondary MN. However, the outcome may be different, being often related to that of the original disease in secondary MN. Also, the treatment may be different, being targeted to the etiologic cause in secondary MN. Thus, the differential diagnosis between primary and secondary MN is critical and should be based not only on history and clinical features of the patient but also on immunofluorescence and electron microscopy analysis of renal biopsy as well as on the research of circulating antibodies. The identification of the pathologic events underlying a secondary MN is of paramount importance, since the eradication of the etiologic factors may be followed by remission or definitive cure of MN. In this review we report the main diseases and drugs responsible of secondary MN, the outcome and the pathogenesis of renal disease in different settings and the possible treatments.

Biomarkers and Diagnostic Testing for Renal Disease in Sjogren's Syndrome

Primary Sjogren's syndrome (pSS) is an autoimmune disorder in which lymphocytic infiltration leads to lacrimal and salivary glands dysfunction, which results in symptoms of dryness (xerophthalmia and xerostomia). Extraglandular features are common and may affect several organs. Renal involvement has long been known as one of the systemic complications of pSS. The most classical lesion observed in pSS is tubulointerstitial nephritis (TIN) and less frequently membranoproliferative glomerulonephritis (MPGN), which is related to cryoglobulinemia. In some cases, renal biopsy is necessary for the definitive diagnosis of kidney involvement. Patients may present with proximal renal tubular acidosis, distal renal tubular acidosis and chronic kidney disease. Response to treatment is usually favorable. However, occasionally severe and rarely lethal outcomes have been described. Recently, several case series and cross-sectional studies have been published which investigated the factors associated with renal involvement in pSS and the most accurate screening tests for early detection. The presence of xerophthalmia, anti-SSA and rheumatoid factor positivity, low C3 levels and other features have all shown either positive or inverse associations with the development of renal complications. Serum creatinine, alpha-1-microglobulin, cystatin-C have been evaluated as early detection biomarkers with variable accuracy. More advanced techniques may be necessary to confirm proximal and distal renal tubular acidosis, along with nephrogenic diabetes insipidus. The aim of the current paper is to summarize and critically examine these findings in order to provide updated guidance on serum biomarkers and further testing for kidney involvement in pSS.

Membranous nephropathy with masked polyclonal IgG deposits associated with primary Sjögren's syndrome

Tubulointerstitial nephritis and renal tubular acidosis are well-known renal involvements with primary Sjögren's syndrome. However, several types of glomerulonephritis such as membranoproliferative glomerulonephritis and membranous nephropathy are also known to develop in patients with this syndrome. We here report a case of membranous nephropathy that developed 8 years after a diagnosis of primary Sjögren's syndrome in a female patient. Interestingly, the deposition was not identified by routine immunofluorescence using snap frozen tissue, but was revealed by immunofluorescence on formalin-fixed paraffin-embedded sections treated with proteinase K. We further performed immunofluorescence analysis on the treated paraffin-embedded sections with the identified antigen but found that the deposited IgG was not monoclonal and that serum amyloid P, a sensitive marker for membranous-like glomerulopathy with masked IgG κ deposits, was not evident in the glomeruli. To the best of our knowledge, this report depicted the first case of masked polyclonal IgG deposits and further analysis is needed to clarify the underlying mechanisms of IgG masking and possible association with autoantibodies.

Primary Sjögren syndrome-associated acute interstitial nephritis and type 3 renal tubular acidosis in a patient with thin basement membrane nephropathy: A case report

INTRODUCTION

The kidney is one of the common extraglandular sites involved in primary Sjögren syndrome (pSS), with chronic tubulointerstitial nephritis (TIN) the most common pathology type. Renal involvement in pSS often presents as chronic TIN accompanied by type 1 or 2 renal tubular acidosis (RTA). Description of renal involvement as acute TIN with type III RTA in pSS has been rarely reported.

PATIENT CONCERNS

A 37-year-old woman was admitted with complaints of dry mouth, dry eyes, and progressive muscle weakness for 17 months. Two months before admission, the patient had a blood potassium level of 1.7 mmol/L.

DIAGNOSIS

Further tests confirmed pSS and type III RTA. Renal biopsy demonstrated acute TIN and thin basement membrane nephropathy (TBMN).

INTERVENTIONS

Full-dose corticosteroid (1 mg/kg/day) and cyclophosphamide (100 mg/day) were applied.

OUTCOMES

The creatinine levels of the patient decreased 0.28 mg/dL (1.18-0.90 mg/dL) during 3-month follow-up.

CONCLUSIONS

We reported a patient with pSS-associated kidney injury, presenting as acute TIN with type 3 RTA and TBMN. This case increases the awareness of a rare manifestation of pSS-associated kidney injury. In pSS-associated acute TIN, cyclophosphamide combined with full-dose corticosteroids may achieve good outcomes.

Renal disorders in rheumatologic diseases: the spectrum is changing (Part 1: connective tissue diseases)

The kidney is frequently involved by autoimmune rheumatic diseases. The renal manifestations may be variable, ranging from asymptomatic proteinuria and microscopic haematuria to nephrotic syndrome and rapidly progressive glomerulonephritis or vasculitis. In a number of cases the kidney involvement is related to the treatment of the original disease and may represent a major cause of morbidity and mortality. Thus, it is important for nephrologists and rheumatologists to remember that dysfunction of the kidney may be part of the primary systemic disorder or consequence of its pharmacotherapy. In the first part of this review we will analyse the kidney involvement in four autoimmune connective tissue diseases: systemic lupus erythematosus, Sjögren syndrome, polymyositis/dermatomyositis, and systemic sclerosis. Renal disease is common in lupus and is a main cause of morbidity and mortality. About 10% of patients with Sjögren syndrome may present interstitial nephritis or, more rarely, glomerulonephritis. Myoglobinuria and acute kidney injury is a frequent complication of polymyositis. Renal disease is one of the most serious complications of systemic sclerosis and may present with a dramatic renal crisis, characterized by malignant hypertension, oligo-anuria, and microangiopathic thrombocytopenic anaemia.

Nephrological disorders and neurological involvement in pediatric primary Sjogren syndrome:a case report and review of literature

BACKGROUND

Sjögren syndrome (SS) is a rare disease in pediatrics, and little attention has been paid to the clinical feature in these patients. To date, there are few cases concern about neurological and nephrological disorders in childhood Sjögren syndrome. We describe a case of Sjögren syndrome in a 12-year-old girl who developed neurological disorders and interstitial nephritis and review the literature currently available on this topic.

CASE PRESENTATION

A 12-year-old girl was admitted to our hospital for arthritis and glucosuria. She was required to do labial gland and renal biopsy, because the positive for anti-nuclear antibody and anti-Sjögren syndrome B (anti-SSB) antibody. Then the biopsy was performed revealing the lymphocytic infiltrate in the small area and renal tubular interstitial damage,thus the diagnosis of Sjögren syndrome with tubular interstitial damage was made. Three months later, she presented again with headache, fever, nausea, vomiting and was recovered without drug therapy. Based on the patient's medical history, laboratory and imaging examination, and treatment, we speculate that the disorders of the nervous system were caused by the Sjögren syndrome. The girl has stable renal function and no residual nervous system damage in the next 1.5 years, but she underwent low dose prednisone therapy because of persistent renal glucosuria.

CONCLUSIONS

Nephrological disorders and neurological involvement are rare manifestations of Sjögren syndrome in children, and rarely presented as the initial symptoms. It should be suspected in children presenting with unexplained renal diseases, neurological abnormalities, or unexplained fever. Although there is no guidelines on the diagnosis and treatment of children Sjögren syndrome are currently available, early recognition and the appropriate treatment of renal damage and neurologic involvement would improve prognosis and prevent complications.

Primary Sjӧgren's syndrome with renal Fanconi syndrome: Good responses to treatment with glucocorticoids

BACKGROUND

Renal Fanconi syndrome (FS) is rare in primary Sjӧgren's syndrome (pSS). We aimed to describe the clinicopathological characteristics of pSS associated FS (pSS-FS) and its responses to treatment.

METHODS

We reported 25 cases of pSS-FS patients and retrospectively reviewed their clinical records, kidney pathology and follow-up data.

RESULTS

The 25 pSS-FS patients were mainly female (92.0%) and the mean age at diagnosis was 43.6±11.3 years. They showed different degrees of proximal tubular dysfunctions and eGFR decline (60.9±32.3 ml/min/1.73m²). Kidney pathology of pSS-FS patients showed tubulo-interstitial nephritis with defective brush border and lymphoplasmacytic infiltrates. After glucocorticoid treatment, the eGFR levels were significantly improved from 48.3±20.6 ml/min/1.73m² to 55.0±19.9 ml/min/1.73m² (P = 0.012) at the third month of follow-up. They also acquired good tubular (88.2%) and immunological (90.0%) responses. pSS-FS patients with young-onset pSS presented with a higher prevalence of positive anti-SSB antibody and hypocomplementemia, more severe hypokalemia, and better eGFR levels.

CONCLUSIONS

In pSS-FS patients, use of glucocorticoids could improve eGFR and tubular functions. The young-onset pSS group presented with a particular pattern in immunological features and kidney involvement.

Autoimmune diseases in China

Autoimmune diseases, such as rheumatoid arthritis, systematic lupus erythematosus and Sjögren's syndrome, are a group of diseases characterized by the activation of immune cells and excessive production of autoantibodies. Although the pathogenesis of these diseases is still not completely understood, studies have shown that multiple factors including genetics, environment and immune responses play important roles in the development and progression of the diseases. In China, there are great achievements in the mechanisms of autoimmune diseases during the last decades. These studies provide new insight to understand the diseases and also shed light on the development of novel therapy.

Mesenchymal Stem Cells Extract (MSCsE)-Based Therapy Alleviates Xerostomia and Keratoconjunctivitis Sicca in Sjogren's Syndrome-Like Disease

Sjogren’s syndrome (SS) is an autoimmune disease that manifests primarily in salivary and lacrimal glands leading to dry mouth and eyes. Unfortunately, there is no cure for SS due to its complex etiopathogenesis. Mesenchymal stem cells (MSCs) were successfully tested for SS, but some risks and limitations remained for their clinical use. This study combined cell- and biologic-based therapies by utilizing the MSCs extract (MSCsE) to treat SS-like disease in NOD mice. We found that MSCsE and MSCs therapies were successful and comparable in preserving salivary and lacrimal glands function in NOD mice when compared to control group. Cells positive for AQP5, AQP4, α-SMA, CK5, and c-Kit were preserved. Gene expression of AQP5, EGF, FGF2, BMP7, LYZ1 and IL-10 were upregulated, and downregulated for TNF-α, TGF-β1, MMP2, CASP3, and IL-1β. The proliferation rate of the glands and serum levels of EGF were also higher. Cornea integrity and epithelial thickness were maintained due to tear flow rate preservation. Peripheral tolerance was re-established, as indicated by lower lymphocytic infiltration and anti-SS-A antibodies, less BAFF secretion, higher serum IL-10 levels and FoxP3⁺ T_reg cells, and selective inhibition of B220⁺ B cells. These promising results opened new venues for a safer and more convenient combined biologic- and cell-based therapy.

Nephrotic Syndrome due to Focal Segmental Glomerulosclerosis Complicating Sjögren's Syndrome: A Case Report and Literature Review

Background

Renal tubular acidosis and tubulointerstitial nephritis constitute the primary renal complications associated with Sjögren's syndrome (SjS), and glomerulonephritis and nephrotic syndrome are rare.

Case Presentation

A 79-year-old Japanese woman presented with bilateral leg edema and weight gain and was diagnosed with nephrotic syndrome. In addition, she reported a 5-year history of dryness of mouth and was diagnosed with SjS. Renal biopsy revealed segmental glomerulosclerosis, with some specimens showing collapse of the glomerular capillary loops, proliferation of glomerular epithelial cells, and sclerotic lesions at the tubular poles, without spike formation, double contour lesions, or any other changes of the glomerular basement membrane. Immunofluorescence staining showed no immune complex (immunoglobulin IgG, IgA, or IgM) or complement (C3) deposition in the glomerular capillary walls. Based on these findings, she was diagnosed with focal segmental glomerulosclerosis (FSGS). The administration of steroid and cyclosporine achieved complete remission of nephrotic syndrome.

Conclusion

Although glomerular diseases are rare, a variety of glomerular lesions including FSGS are reported in patients with SjS. Therefore, renal biopsy is warranted in patients with SjS presenting with severe urinary abnormalities.

Renal tubular acidosis as the initial presentation of Sjögren's syndrome

We present a 44-year-old female with an initial presentation with distal renal tubular acidosis (RTA) after she presented with hypokalaemia and normal anion gap acidosis. Three years following the diagnosis, she presented with progressive renal impairment. In the absence of any clinical, biochemical and radiological clues, she underwent a renal biopsy which showed severe tubulitis secondary to lymphocytic infiltration. Serological investigations subsequently revealed positive anti-nuclear, anti-Sjögren’s syndrome related antigen A (SS-A), and anti-Sjögren’s syndrome related antigen B (SS-B) antibodies, supporting the diagnosis of Sjögren’s syndrome. This case is unique in that distal RTA was the presenting clinical manifestation of Sjögren’s syndrome. We hope that a consideration for Sjögren’s syndrome is made in patients with seemingly idiopathic RTA.

Presence of serum autoantibodies to vacuolar H+ -ATPase in patients with renal tubular acidosis

OBJECTIVE

Concomitant presence of renal tubular acidosis (RTA) and autoimmune diseases is indicative of the potential role of immune factors in the pathogenesis of RTA. Our study aimed to detect the serum antibodies to renal tubular epithelial cells in RTA patients.

METHODS

We enrolled 11 RTA patients, eight primary Sjögren's syndrome (pSS) patients and eight healthy controls (HC). Serum biochemical test, urinary regular test, and 24 hours urinary protein quantification were measured using a fully automated analyzer. Immunofluorescence assay was performed to detect the antibodies to subunit B1 and subunit B2 of v-H+-ATPases (adenosine triphosphatases) in the serum of the participants.

RESULTS

Clinically, RTA patients showed hyperchloremia, acidosis and paradoxical alkaline urine. We detected the serum antibodies to renal tubular epithelial cells and there were 6/11 positive in RTA patients, much higher than that in the pSS group (0/8) and the HC group (0/8). Subsequently, we demonstrated that in normal renal tissue, the B1 subunit of v-H+-ATPase specifically expressed in intercalated cells, while the B2 subunit continuously expressed along the lumen of renal tubular epithelial cells. Moreover, the antibody to subunit B1/B2 of v-H+-ATPase was positive in the sera of 6 RTA patients (54%), while it was negative in both the pSS and HC group.

CONCLUSIONS

We detected the presence of serum autoantibodies to subunit B1 and subunit B2 of v-H⁺ -ATPase in RTA patients. Our findings may provide novel mechanism insights into the pathogenesis of RTA and the potential diagnostic utility of antibodies to v-H⁺ -ATPase in the classification of RTA.

Clinical features and potential relevant factors of renal involvement in primary Sjögren's syndrome

OBJECTIVE

To investigate distinct features of renal involvement in patients with primary Sjögren's syndrome (pSS) and to identify potential factors associated with renal involvement.

METHODS

Four hundred and thrity-four pSS patients from the Rheumatology Department of the First Affiliated Hospital of Wenzhou Medical University from 2013 to 2017 were included in a cross-sectional study. Patients with renal involvement were compared with their age- and gender-matched controls (pSS without renal involvement). Demographic, clinical, histological, nephritic, immunological features of renal involvement in pSS were systematically analyzed. Possible factors related to renal involvement were identified using multivariate logistic regression analyses.

RESULTS

One hundred and ninety-two pSS patients (88.48%) with renal involvement were women with mean age of nearly 58 years and mean disease duration of above 4 years. Clinical manifestation, serologic and immunological features and renal biopsy class of the pSS patients with renal involvement were presented. By multivariate analyses, xerophthalmia, histological positivity for lower salivary gland biopsy (LSGB), anti-SSA/Ro52-positive, reduced complement 3 (C3) levels, hypoalbuminemia and anemia retained significant association with renal involvement in pSS (all P < 0.05).

CONCLUSION

In addition to LSGB pattern, anti-SSA/Ro52-positivity, reduced C3 levels, hypoalbuminemia and anemia, also indicate significant association with renal involvement in pSS. Therefore, early vigilance is required for patients with these clinical manifestations.