Kidney biopsy findings in primary Sjögren syndrome

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.

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.

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.

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.

Genetic diagnosis and treatment of hereditary renal tubular disease with hypokalemia and alkalosis

Renal tubules play an important role in maintaining water, electrolyte, and acid-base balance. Renal tubule dysfunction can cause electrolyte disorders and acid-base imbalance. Clinically, hypokalemic renal tubular disease is the most common tubule disorder. With the development of molecular genetics and gene sequencing technology, hereditary renal tubular diseases have attracted attention, and an increasing number of pathogenic genes related to renal tubular diseases have been discovered and reported. Inherited renal tubular diseases mainly occur due to mutations in genes encoding various specific transporters or ion channels expressed on the tubular epithelial membrane, leading to dysfunctional renal tubular reabsorption, secretion, and excretion. An in-depth understanding of the molecular genetic basis of hereditary renal tubular disease will help to understand the physiological function of renal tubules, the mechanism by which the kidney maintains water, electrolyte, and acid-base balance, and the relationship between the kidney and other systems in the body. Meanwhile, understanding these diseases also improves our understanding of the pathogenesis of hypokalemia, alkalosis and other related diseases and ultimately promotes accurate diagnostics and effective disease treatment. The present review summarizes the most common hereditary renal tubular diseases (Bartter syndrome, Gitelman syndrome, EAST syndrome and Liddle syndrome) characterized by hypokalemia and alkalosis. Further detailed explanations are provided for pathogenic genes and functional proteins, clinical manifestations, intrinsic relationship between genotype and clinical phenotype, diagnostic clues, differential diagnosis, and treatment strategies for these diseases.

Distal Renal Tubular Acidosis in Patients with Autoimmune Diseases—An Update on Pathogenesis, Clinical Presentation and Therapeutic Strategies

Distal renal tubular acidosis (DRTA) has been reported in association with autoimmune diseases, such as Sjögren’s syndrome, systemic lupus erythematosus (SLE), autoimmune hepatitis, primary biliary cirrhosis, rheumatoid arthritis and autoimmune thyroiditis. Whether we talk about the complete or incomplete form of DRTA associated with autoimmune diseases, the real incidence is unknown because asymptomatic patients usually are not identified, and most of the reported cases are diagnosed due to severe symptoms secondary to hypokalemia, a frequent finding in these cases. The mechanisms involved in DRTA in patients with autoimmune diseases are far from being fully elucidated and most of the data has come from patients with Sjögren’s syndrome. This review will present different hypotheses raised to explain this association. Also, aiming for a better understanding of the association between autoimmune diseases and DRTA, our review summarizes data from 37 case reports published in the last five years. We will emphasize data regarding clinical presentation, biological alterations, treatment and outcome. A very important question is whether immunosuppressive therapy is helpful in DRTA associated with autoimmune diseases. Because the pathology is rather rare, treatment is not standardized, and reported results are often contradictory. Corticosteroids are frequently used, but multiple other immunosuppressive drugs have been proposed and will be approached in this review.

Sjögren's Syndrome-Related Organs Fibrosis: Hypotheses and Realities

Sjögren's syndrome (SS) is a systemic chronic autoimmune disorder characterized by lymphoplasmacytic infiltration of salivary glands (SGs) and lacrimal glands, causing glandular damage. The disease shows a combination of dryness symptoms found in the oral cavity, pharynx, larynx, and vagina, representing a systemic disease. Recent advances link chronic inflammation with SG fibrosis, based on a molecular mechanism pointing to the epithelial to mesenchymal transition (EMT). The continued activation of inflammatory-dependent fibrosis is highly detrimental and a common final pathway of numerous disease states. The important question of whether and how fibrosis contributes to SS pathogenesis is currently intensely debated. Here, we collect the recent findings on EMT-dependent fibrosis in SS SGs and explore clinical evidence of multi-organ fibrosis in SS to highlight potential avenues for therapeutic investigation.

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.

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'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.

Renal Disease in Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder characterised by lymphocytic infiltration of the exocrine glands, predominantly the salivary and lacrimal glands, leading to sicca symptoms. Patients may have extraglandular disease involving multiple organs, including the kidneys. 5% of patients with pSS can have renal involvement. Kidney disease in pSS presents a diagnostic challenge, as clinical symptoms are often insidious and can precede sicca symptoms. pSS affects the kidney through lymphocytic infiltration of renal tubules or immune complex deposition, leading to an array of clinical features. Tubulointerstitial nephritis is the most common histological pattern of kidney disease. Other tubular injuries include renal tubular acidosis with hypokalaemia, Fanconi's syndrome and diabetes insipidus. Glomerular disease is less common and typically involves an immune complex-mediated process. Optimal treatment for kidney diseases in pSS is not established, and treatment is guided by the pattern of disease. For tubulointerstitial nephritis, management involves electrolyte imbalance correction and the use of immunosuppression, including steroids. Treatment of glomerular disease is targeted to the histological pattern, and often requires a combination of immunosuppressive agents. The risk of end-stage kidney disease is low. Nevertheless, patients with pSS and kidney disease have significantly reduced quality of life.

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.

[Renal involvement in Sjögren's syndrome]

Primary Sjögren syndrome is an autoimmune disorder characterized by lymphoplasmacytic infiltration of the exocrine (salivary and lachrymal) glands resulting in sicca symptoms (dryness). Systemic complications can occur in primary Sjögren syndrome, but renal involvement is rare, affecting<10% patients. The most frequent form of nephropathy in primary Sjögren syndrome is tubulointerstitial nephritis, where infiltration of the kidney by plasma cells is a key feature and shows similarity to the lymphoplasmacytic infiltration of the salivary glands. Electrolyte disturbances may occur in primary Sjögren syndrome, such as renal distal tubular acidosis, diabetes insipidus, Gitelman syndrome, or Fanconi syndrome. Glomerular involvement is less frequently detected in patients with primary Sjögren syndrome, but can take the form of membranoproliferative glomerulonephritis secondary to cryoglobulinaemia. The renal prognosis in patients with primary Sjögren syndrome and TIN or glomerular disease is usually good, but the risk of chronic kidney disease remains significant for some patients. Appropriate screening must be performed at least once a year in patients with systemic primary Sjögren syndrome in order to facilitate the early detection of renal complications. In this Review, we discuss the epidemiology, pathophysiology, differential diagnosis, and treatment of renal disease in primary Sjögren syndrome.

Clinical practice guidance for Sjögren's syndrome in pediatric patients (2018) - summarized and updated

There are a considerable number of pediatric patients with Sjögren's syndrome (SS); however, SS is generally considered rare among children. Pediatric patients with SS report fewer sicca symptoms; therefore, many are under-diagnosed and cannot access appropriate medical management. Therefore, we propose a newly developed guidance for the diagnosis, treatment, and management of pediatric SS, including epidemiology, clinical features, and diagnostic examination methodology. The aim of this guidance was to standardize the medical care of pediatric SS in Japan, and we published the Japanese version by YODOSHA in 2018. This article is the English version, which is summarized and updated. This guidance will need to be revised in the near future as additional clinical data become available.

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.

Ocular Clinical Signs and Diagnostic Tests Most Compatible With Keratoconjunctivitis Sicca: A Latent Class Approach

PURPOSE

To evaluate the ocular signs and tests for keratoconjunctivitis sicca (KCS) in the absence of a gold standard.

METHODS

Cross-sectional study of participants from the Sjögren's International Collaborative Clinical Alliance (SICCA) registry. Participants had oral/ocular/rheumatologic examinations, blood/saliva samples collected, and salivary gland biopsy. Latent class analysis (LCA) identified clusters of patients based on 3 to 4 predictor variables relating to signs or tests of KCS. The resulting model-based "gold standard" classification formed the basis for estimated sensitivity and specificity associated with these predictors.

RESULTS

A total of 3514 participants were enrolled into SICCA, with 52.9% classified as SS. LCA revealed a best-fit model with 2 groups. For the gold standard-positive group, an abnormal tear breakup time, ocular staining score (OSS), and Schirmer I had a sensitivity of 99.5%, 91.0%, and 47.4%, respectively. For the gold standard-negative group, an abnormal tear breakup time, OSS, and Schirmer I had a specificity of 32.0%, 84.0%, and 88.5%, respectively. OSS components (fluorescein and lissamine staining), exhibited a sensitivity of 82.6% and 90.5%, respectively, in the gold standard-positive group, whereas these signs in the gold standard-negative group had a specificity of 88.8% and 73.0%, respectively.

CONCLUSIONS

OSS and its components (fluorescein and lissamine staining) differentiated 2 groups from each other better than other KCS parameters and had relatively high sensitivity and specificity.

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 Sjogren's syndrome presenting as autoimmune cytopenia

Sjogren's syndrome (SS) is a chronic systemic autoimmune disease, characterized by lymphocytic infiltration of lacrimal and salivary glands. Although extra glandular manifestations are uncommon, they can occur with the musculoskeletal, renal, pulmonary and hematological disease. We report the case of a 35-year-old woman presented to us with persistent unexplained bicytopenia (anemia and thrombocytopenia). Antinuclear antibody and direct Coombs test were positive. Anti-Ro/SSA and anti-La/SSB antibodies were also positive in high titer. The final diagnosis of primary SS with autoimmune cytopenia was made. Cytopenias in SS are rarely reported. Our case illustrates that clinically significant cytopenias may present as an extraglandular manifestation of SS.

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.

Clinical significance of C4d deposition in renal tissues from patients with primary Sjögren's syndrome-a preliminary study

Background

To evaluate renal expression of C4d, a complement component in the classical/mannose binding lectin (MBL) pathway, in patients with primary Sjögren’s syndrome (pSS)-associated renal impairments.

Methods

We retrospectively reviewed the clinical and pathological data from 39 patients with pSS presenting with renal impairments. C4d was examined in paraffin-embedded biopsy tissues using immunohistochemistry. Glomerular C4d positive was defined when > 75% glomeruli were globally stained. Tubulointerstitial C4d (TI-C4d) were scored semi-quantitatively as 0 (absent), 1 (spotty or weak), 2 (patchy) and 3 (diffuse). A TI-C4d score ≥ 2 was considered TI-C4d positive and included in the TI-C4d⁺ group and vice versa. Peritubular capillary (PTC) C4d was scored as 0 (absent), 1 (0~10%, minimal), 2 (10%~ 50%, focal), and 3 (> 50%, diffuse).

Results

Glomerular C4d deposition was observed in all 8 patients with pSS-related membranous nephropathy (MN) without obvious C1q deposition. Two of 5 patients with mesangial proliferative glomerulonephritis and 1 of 2 patients with IgA nephropathy had mild mesangial C4d deposition. Sixteen patients (6 glomerular dominant and 10 tubulointerstitial dominant) presented TI-C4d score ≥ 2. Patients in the TI-C4d⁺ group exhibited a higher serum creatinine level at the time of renal biopsy (TI-C4d⁺ 132.5 [89.7, 165.5] vs. TI-C4d⁻ 83.0 [70.7, 102.0] μmol/L, P = 0.008). PTC C4d was observed in 12 patients, with each of minimal, focal and diffuse staining being noted in 4 patients.

Conclusions

The MBL pathway of complement activation was potentially involved in pSS-related MN. Tubulointerstitial C4d might be a pathological marker of severe renal injury in patients with pSS-related renal impairments.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1341-y) contains supplementary material, which is available to authorized users.

Pathological changes of renal biopsy in Sjögren Syndrome

We are presenting the case of a 53-year-old woman with a history of Sjögren syndrome and a secondary antiphospholipid syndrome admitted at the Nephrology department for the evaluation of renal failure. The patient was initially diagnosed with tubulointerstitial nephritis and subsequently a membranoproliferative type I glomerulonephritis, secondary to cryoglobulins during the course of the disease. Repeated renal biopsies were required to confirm the diagnosis.

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.

Renal Tubular Acidosis and Hypokalemic Paralysis as a First Presentation of Primary Sjögren's Syndrome

Sjögren's syndrome is an autoimmune disease with multisystem involvement and varying clinical presentation. We report the clinical course and outcome of a case who presented with repeated episodes of hypokalemia mimicking hypokalemic periodic paralysis and metabolic acidosis, which was later diagnosed as distal renal tubular acidosis secondary to primary Sjögren's syndrome. A 50-year-old lady, who was previously diagnosed as hypokalemic periodic paralysis, presented with generalized weakness and fatigue. She was found to have severe hypokalemia with normal anion-gap metabolic acidosis consistent with distal renal tubular acidosis. Subsequent evaluation revealed Sjögren's syndrome as the cause of her problems. Kidney biopsy done to evaluate significant proteinuria revealed nonproliferative morphology with patchy acute tubular injury and significant chronic interstitial nephritis. The patient responded well to potassium supplementation and oral prednisolone. Presentation of this case highlights the necessity of close vigilance while managing a case of repeated hypokalemia, which could be one of the rare clinical manifestations of Sjögren's syndrome.

Acute and Chronic Tubulointerstitial Nephritis of Rheumatic Causes

Tubulointerstitial nephritis (TIN) is the second most common cause of acute intrinsic kidney injury after acute tubular necrosis. Although drug-induced forms of TIN represent the vast majority, rheumatic disease is another common cause and often underdiagnosed. Early diagnosis of acute interstitial nephritis and prompt withdrawal of the culprit medication or a correct treatment can avoid chronic damage and progressive chronic kidney disease. This review highlights the recent updates, clinical features, and treatment in TIN in autoimmune rheumatic disease.

Biopsy-proven renal involvement and prognosis in 13 hispanic patients with primary Sjögren syndrome

BACKGROUND

The aim of this study was to describe a case series of 13 Hispanic patients with primary Sjögren syndrome (pSS) and biopsy-proven renal involvement.

METHODS

We describe the clinical, serological and histological characteristics as well as the prognosis in a group of patients with pSS and biopsy-proven renal involvement, treated in 2 referral nephrology units in Mexico City.

RESULTS

Thirteen patients with pSS underwent kidney biopsy (KB) over a period of 27 years. The median duration from pSS diagnosis to KB was 13.9 months. Seven patients (54%) had glomerulonephritis and 6 patients (46%) had tubulointerstitial nephritis. All patients were treated with corticosteroids and/or immunosuppressants. Eight patients (62%) remained stable or their renal function improved after a median follow-up of 12 months.

CONCLUSIONS

This case series reflects the broad spectrum of renal involvement in pSS. We observed that in our Hispanic population, glomerular involvement was the most frequent abnormality, mainly membranous glomerulopathy, followed by tubulointerstitial disease. Tubular atrophy and interstitial fibrosis were also common biopsy findings. Treatment with corticosteroids or other immunosuppressive agents appear to slow renal disease progression.

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

AIM

To retrospectively investigate the features of renal involvements in patients with primary Sjögren's syndrome (pSS) with biopsy results.

METHODS

A total of 2096 pSS inpatients at Peking Union Medical College Hospital in China from 2005 to 2015 were identified. Patients with biopsy-proven renal involvement (SS-renal) and matched controls (SS-only) were recruited. The clinical and pathologic features as well as treatments and outcomes were systematically analyzed.

RESULTS

One hundred and three pSS nephritis (inpatients had biopsy-proven renal involvement. Tubulointerstitial 53, 51.5%) was the prominent pathologic pattern with glomerulonephritis (GN) present in 50 (48.5%) of the renal lesions. The patterns of GN lesions included membranous nephropathy (37, 35.9%), mesangial proliferative glomerulonephritis (six, 5.8%) or immunoglobulin A nephropathy (three, 2.9%), minimal change disease (four, 3.9%) and focal segmental glomerulosclerosis (three, 2.9%). Compared to SS-only patients, SS-renal patients had fewer dry eyes and positive objective xerostomia (P < 0.05). They presented with a significantly lower incidence of interstitial lung disease (ILD), leukocytopenia and elevated immunoglobulin G levels (P < 0.05). They received a larger initial dosage of corticosteroid and had a higher mortality rate (P < 0.05).

CONCLUSION

This Chinese SS-renal population with biopsy results has diverse pathologic patterns and distinct clinical features. They are characterized with prominent renal-associated and mild SS-associated features. They received more vigorous treatment but had poorer prognosis.

Hypokalemic Paralysis: A Hidden Card of Several Autoimmune Diseases

Acute hypokalemic paralysis is a rare and potentially fatal condition, with few related causes, one of which highlights distal renal tubular acidosis (dRTA). Distal renal tubular acidosis is a rare complication of several autoimmune diseases such as systemic lupus erythematosus, Sjögren's syndrome, and Hashimoto thyroiditis. We report a case of a lupic patient who presented rapidly progressive quadriparesis in the context of active renal disease. Research revealed severe refractory hypokalemia, metabolic acidosis, and alkaline urine suggestive of dRTA. We diagnosed Sjögren's syndrome based on sicca symptoms, an abnormal salivary glands' nuclear scan and the presence of anti-Ro/SSA and anti-La/SSB. In addition, the finding of thyroid peroxidase, thyroglobulin antibodies, and hypothyroidism led us to the diagnosis of Hashimoto thyroiditis. Due to the active renal involvement on the context of systemic lupus erythematosus and Sjögren's syndrome, the patient received immunosuppression with rituximab, resulting in a progressive and complete improvement.

Overview of IgG4-Related Tubulointerstitial Nephritis and Its Mimickers

Tubulointerstitial nephritis (TIN) is the most common form of renal involvement in IgG4-related disease. It is characterized by a dominant infiltrate of IgG4-positive plasma cells in the interstitium and storiform fibrosis. Demonstration of IgG4-positive plasma cells is essential for diagnosis, but the number of IgG4-positive cells and the ratio of IgG4-positive/IgG-positive plasma cells may vary from case to case and depending on the methods of tissue sampling even in the same case. IgG4-positive plasma cells can be seen in TIN associated with systemic lupus erythematosus, Sjögren syndrome, or anti-neutrophil cytoplasmic antibody–associated vasculitis, which further add diagnostic confusion and difficulties. To have a more clear view of IgG4-TIN and to delineate differential points from other TIN with IgG4-positive plasma cell infiltrates, clinical and histological features of IgG4-TIN and its mimickers were reviewed. In the rear part, cases suggesting overlap of IgG4-TIN and its mimickers and glomerulonephritis associated with IgG4-TIN were briefly described.