Accelerated involution of germinal center in palatine tonsils in IgA nephropathy.

BACKGROUND: Altered immunological responses in the palatine tonsils may be involved in the pathogenesis of IgA nephropathy (IgAN). The germinal center serves as the site for antigen-specific humoral immune responses in the palatine tonsils. Germinal center involution is frequently observed in the palatine tonsils of IgAN (IgAN tonsils). However, the pathogenic significance of these characteristic changes remains unclear. This study aimed to investigate the morphological changes in secondary lymphoid follicles in IgAN tonsils and to evaluate the correlation between the morphometric results and the clinicopathological severity of IgAN. METHODS: The tonsils of age-matched patients with recurrent tonsillitis (RT tonsils) were used as controls. The correlation between the degree of lymphoid follicular involution and histopathological severities in clinical or kidney biopsy was evaluated. RESULTS: In total, 87 patients with IgAN were included (48% male, median age 35 years, median estimated glomerular filtration rate: 74 mL/min/1.73 m2). Compared to RT tonsils, IgAN tonsils showed smaller median sizes of lymphoid follicles and germinal centers (P < 0.001). The relative areas of lymphoid follicles (%LFA) and germinal centers (%GCA) in the total tonsillar tissue were smaller in the IgAN tonsils than in the RT tonsils (P < 0.001). In contrast, the median proportion of mantle zones in the total tonsillar tissue was comparable between the groups. A lower %LFA was associated with a longer period from the onset of urinary abnormalities to biopsy diagnosis and higher urinary protein excretion (P = 0.01). %LFA showed significant negative correlations with frequencies of glomeruli with both global and segmental sclerosis. CONCLUSIONS: The present study confirmed accelerated germinal center involution in the tonsils of patients with IgAN. This characteristic change in the IgAN tonsil correlates with heavy proteinuria and advanced chronic histopathological changes in the kidneys, thereby suggesting the involvement of repeated tonsillar immunoreactions during IgAN progression.

A 20-year follow-up study of identical twin sisters with immunoglobulin A nephropathy.

Immunoglobulin A nephropathy (IgAN) is characterized by diverse clinicopathological phenotypes. Herein we present a follow-up study of previously reported identical twin sisters with IgAN. The older sister exhibited more severe kidney histopathology and proteinuria and a lower birthweight than did her younger sister, and only the older sister experienced two childbirths. These raised concerns regarding her kidney outcomes. However, with timely multidisciplinary treatments, the older sister's kidney function remained preserved after 20 years of IgAN history. Our findings indicate the significant contribution of environmental/epigenetic factors to IgAN progression and the need for tailored medical care corresponding to life events.

Granulomatosis with polyangiitis presenting as a solitary renal mass: a case report.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is characterized by necrotizing granulomatous vasculitis involving small-sized vessels in the upper airways, lower airways, and kidneys. Renal pathology is usually characterized by focal segmental necrotizing glomerulonephritis, which often leads to rapidly progressive renal failure. This type of renal involvement is usually unapparent on radiography. The presence of a renal mass in a patient with GPA, although extremely rare, is recognizable. Herein, we report a rare case of GPA presenting as a solitary renal mass and present a review of the literature. CASE PRESENTATION: A 75-year-old woman presented with a solitary right kidney mass measuring 4 × 3.5 cm detected by enhanced computed tomography. There was no history of sinusitis, rhinitis, cough, or pneumonia suggestive of systemic GPA. Nephrectomy was performed based on the suspicion of renal cell carcinoma or malignant lymphoma. Three months later, she was admitted because her serum creatinine levels increased from 54.81 µmol/L to 405.76 µmol/L accompanied by a high C-reactive protein level of 159 mg/L. Anti-neutrophil cytoplasmic antibodies against myeloperoxidase and anti-proteinase 3 were negative. Histological examinations of the solitary renal mass revealed necrotizing granulomatous arteritis in the cortex and medullary vasa recta, surrounded by interstitial fibrosis, and focal segmental necrotizing glomerulonephritis in the localized lesion; however, signs of vasculitis were not observed in areas other than the solitary mass. Therefore, the patient was diagnosed with granulomatosis with polyangiitis (GPA). Despite treatment with prednisolone (30 mg/day), the patient developed oliguria with an elevation of her serum creatinine level to 583.44 µmol/L, which required hemodialysis within one month after the initiation of steroid therapy. The patient could successfully discontinue hemodialysis 21 months later, following a decrease in her serum creatinine level to 251.06 µmol/L. CONCLUSIONS: GPA should be considered as one of the differential diagnoses of a solitary renal mass. Furthermore, patients with solitary renal masses associated with GPA may exhibit a favorable response to steroid or immunosuppressive treatment.

Gross Hematuria Following SARS-CoV-2 Infection in IgA Nephropathy: A Report of 5 Cases.

Gross hematuria after upper respiratory tract infections is a well-known characteristic symptom of immunoglobulin A nephropathy (IgAN). In recent years, there have been several reports of existing or newly diagnosed patients with IgAN susceptible to gross hematuria after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. However, reports of patients with IgAN and gross hematuria after SARS-CoV-2 infection are extremely rare despite a considerable number of patients with coronavirus disease 2019 (COVID-19) who preferentially present with upper respiratory symptoms. Here, we report the cases of 5 Japanese patients with IgAN who developed gross hematuria associated with SARS-CoV-2 infection. These patients presented with fever and other COVID-19-related symptoms, followed by the appearance of gross hematuria within 2 days, which lasted for 1-7 days. Acute kidney injury occurred after gross hematuria in 1 case. In all cases, microhematuria was identified before gross hematuria associated with SARS-CoV-2 infection, and it persisted after the gross hematuria episode. Because repeated gross hematuria and persistent microhematuria may lead to irreversible kidney injury, the clinical manifestations of patients with IgAN during the COVID-19 pandemic should be carefully monitored.

Histiocytic Glomerulopathy With Noncrystalline Inclusion Associated With IgG-Kappa Plasma Cell Dyscrasia.

The kidney pathology of monoclonal gammopathy of renal significance varies greatly. In this report, we present a woman in her 20s with nephrotic syndrome and monoclonal immunoglobulin G kappa (serum and urine) without diabetes. She had a family history of nephrotic syndrome as well as hematologic and connective tissue disorders. A kidney biopsy showed nodular glomerulosclerosis, with the glomerular capillary full of histiocytes, which were strongly positive for kappa, not lambda. Immunoelectron microscopy revealed that histiocytes had infiltrated the glomerular subendothelial space, and enlarged lysosomes of histiocytes contained kappa light chains, without apparent crystalline formation. Bone marrow examination was negative for malignancy; thus, we diagnosed this case as histiocytic glomerulopathy with noncrystalline inclusion associated with immunoglobulin G-kappa plasma cell dyscrasia. Hematologic treatment with bortezomib and daratumumab decreased her level of serum kappa chain and proteinuria. Two years after diagnosis, her kidney function remained normal, urinary protein level decreased to 1 g/d, and free light-chain ratio decreased to 3.1.

Possible Use of Non-purine Selective Xanthine Oxidoreductase Inhibitors for Prevention of Exercise-induced Acute Kidney Injury Associated with Renal Hypouricemia.

Exercise-induced acute kidney injury (EIAKI) is frequently complicated with renal hypouricemia (RHUC). In patients with RHUC, limiting anaerobic exercise can prevent EIAKI. However, it is challenging to reduce exercise intensity in athletes. We herein report a 16-year-old Japanese football player with familial RHUC with compound heterozygous mutations in urate transporter 1 (URAT1) who presented with recurrent EIAKI. As prophylaxis (hydration during exercise) could not prevent EIAKI, febuxostat was initiated. EIAKI was not observed for 16 months despite exercising intensively. Hence, non-purine-selective xanthine oxidoreductase inhibitors may decrease the incidence of EIAKI in athletes with RHUC.

Different Clinical Courses of Nephronophthisis in Dizygotic Twins.

Siblings with nephronophthisis occasionally show different clinical courses; however, the reasons for this remain unclear. We herein report cases of nephronophthisis in a pair of dizygotic twins with different clinical courses. The brother developed end-stage kidney disease at 17 years old; however, his sister did not show kidney insufficiency. Kidney biopsies revealed severe tubulointerstitial damage at 14 and 22 years old in the brother and sister, respectively. Both had a homozygous NPHP1 deletion with different heterozygous mutations related to hereditary cystic kidney disease. Since the dizygotic twins were exposed to similar environmental factors, genetic factors may have influenced their clinical course more strongly than environmental factors.

Tubulointerstitial nephritis: a biopsy case series of 139 Japanese patients.

BACKGROUND: Tubulointerstitial nephritis (TIN) is an important cause of acute kidney injury (AKI) and advanced CKD. Only a limited number of studies have reported etiology-based differences in the clinical and/or histopathological properties and kidney outcomes of the biopsy-proven TIN. METHODS: Patients with biopsy-proven TIN identified from 2005 to 2016 in five hospitals were categorized based on the etiologies and were retrospectively analyzed in relation to the clinicopathological findings and kidney outcomes. RESULTS: Among 4815 biopsy cases screened, 153 Japanese TIN patients were identified, of whom 139 patients with ≥ 6 months of follow-up data (median 58 years old, 45.3% female, median 31.5 months follow-up) were further analyzed. TIN was drug-induced in 32.4%, autoimmune-related in 24.5%, of unknown etiology in 27.3% and other disease-related in 15.8%. Non-steroidal anti-inflammatory drugs and antibiotics were major causative drugs in drug-induced TIN, and IgG4-related disease, Sjögren's syndrome and sarcoidosis were common in autoimmune-related TIN. Among etiology groups, drug-induced TIN showed advanced AKI with elevated serum creatinine (sCr) and increased C-reactive protein levels at the diagnosis. TIN patients with autoimmune diseases showed less-severe AKI, but were more frequently treated with corticosteroids than others. Tubulointerstitial injury expansion in biopsy specimens was comparable among the groups. Complete or partial kidney function recovery at 6 months was more frequent in drug-induced and autoimmune-related TIN than in others. sCr levels at 6 months were similar among the groups. CONCLUSIONS: This largest case series study of the biopsy-proven TIN in Japan provides detailed information regarding both etiology-based clinicopathological properties and kidney outcomes.

Exploring the Physiological and Psychological Effects of Digital Shinrin-Yoku and Its Characteristics as a Restorative Environment.

This study investigated the physiological and psychological therapeutic effects of a digital Shinrin-yoku environment constructed indoors in an urban facility as well as the characteristics of the environment that contribute to restorativeness (restorative traits). We measured the fluctuations in the physical and mental states of 25 subjects by obtaining both before-after measurements and continuous measurements while exposed to a digital Shinrin-yoku environment that reproduced visual, auditory, and olfactory elements. The results demonstrated that the parasympathetic nerve activity was significantly increased and that the heart rate was significantly decreased during the exposure compared with that during the resting state. As for mood, five of the six Profile of Mood States (POMS) scales ("Tension-Anxiety," "Depression," "Anger-Hostility," "Fatigue," and "Confusion") were significantly decreased after the experience. In addition, psychological restorative effects were also confirmed, with a significant decrease in "negative affect" (measured using the Positive and Negative Affect Schedule (PANAS)) and a significant increase in the sense of restorativeness (Restorative Outcome Scale (ROS)) after the experience. In contrast, comparing the digital Shinrin-yoku environment with the actual forest environment and the urban environment using POMS, PANAS, ROS, and Perceived Restorativeness Scale (PRS), the psychological effects and environmental traits of the digital Shinrin-yoku were found to be considerably similar to those of the actual forest environment.

Indirect podocyte injury manifested in a partial podocytectomy mouse model.

In progressive glomerular diseases, segmental podocyte injury often expands, leading to global glomerulosclerosis by unclear mechanisms. To study the expansion of podocyte injury, we established a new mosaic mouse model in which a fraction of podocytes express human (h)CD25 and can be injured by the immunotoxin LMB2. hCD25+ and hCD25- podocytes were designed to express tdTomato and enhanced green fluorescent protein (EGFP), respectively, which enabled cell sorting analysis of podocytes. After the injection of LMB2, mosaic mice developed proteinuria and glomerulosclerosis. Not only tdTomato+ podocytes but also EGFP+ podocytes were decreased in number and showed damage, as evidenced by a decrease in nephrin and an increase in desmin at both protein and RNA levels. Transcriptomics analysis found a decrease in the glucocorticoid-induced transcript 1 gene and an increase in the thrombospondin 4, heparin-binding EGF-like growth factor, and transforming growth factor-ß genes in EGFP+ podocytes; these genes may be candidate mediators of secondary podocyte damage. Pathway analysis suggested that focal adhesion, integrin-mediated cell adhesion, and focal adhesion-phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin signaling are involved in secondary podocyte injury. Finally, treatment of mosaic mice with angiotensin II receptor blocker markedly ameliorated secondary podocyte injury. This mosaic podocyte injury model has distinctly demonstrated that damaged podocytes cause secondary podocyte damage, which may be a promising therapeutic target in progressive kidney diseases.NEW & NOTEWORTHY This novel mosaic model has demonstrated that when a fraction of podocytes is injured, other podocytes are subjected to secondary injury. This spreading of injury may occur ubiquitously irrespective of the primary cause of podocyte injury, leading to end-stage renal failure. Understanding the molecular mechanism of secondary podocyte injury and its prevention is important for the treatment of progressive kidney diseases. This model will be a powerful tool for studying the indirect podocyte injury.

A case of unilateral shoulder joint hydrarthrosis with wild-type amyloidogenic transthyretin amyloidosis.

Wild-type amyloidogenic transthyretin (ATTR) amyloidosis, known as systemic senile amyloidosis (SSA), is an age-related nonhereditary amyloidosis, which is known to cause cardiomyopathy and carpal tunnel syndrome (CTS). Herein, we report a case of unilateral hydrarthrosis with arthritis of the right shoulder joint in an 82-year-old Japanese housewife who has a seven year history of polyneuropathy due to an unknown aetiology. At first, her joint pain was thought to be caused by overuse of her right upper arm. Despite treatment with non-steroidal anti-inflammatory drugs (NSAIDs) and repeated arthrocentesis, her symptoms did not improve. She then visited our hospital, where magnetic resonance imaging (MRI) of her right shoulder suggested synovitis and hydrarthrosis. She also had an arthroscopic synovectomy of the right shoulder joint. The pathological testing revealed a diagnosis of non-specific arthritis with amyloidosis. After further pathological examination, wild-type ATTR was identified and she was diagnosed with senile amyloidosis.

Plasma exchange combined with bortezomib-based chemotherapy is effective for early renal recovery in a patient with IgD-λ type multiple myeloma.

The immunoglobulin (Ig) D type is a rare variant of multiple myeloma (MM), that accounts for 1-2% of all cases. Compared to the more common types of MM, IgD MM is known to have more severe symptoms at presentation, and a poorer prognosis. A woman was admitted to our hospital for severe acute kidney disease and disorder (AKD) and back pain, and was started on hemodialysis. The renal biopsy revealed light chain cast nephropathy. She was diagnosed with IgD-λ MM based on Bence-Jones protein expression and high IgD serum levels, and started bortezomib therapy with plasma exchange (PE). After three sessions of PE, the serum free light chain levels decreased by 92%, and she was withdrawn from dialysis. The patient underwent autologous transplantation and is still in remission, demonstrating the benefits of a bortezomib-based regimen in combination with PE for IgD MM with AKD.

Remission of proteinuria under therapeutic intervention and the renal outcomes in Japanese patients with lupus nephritis class III and IV.

AbstractsBackground: Recent studies have identified the significance of proteinuria levels after initial induction therapies on the renal outcomes in patients with proliferative lupus nephritis, but the issue has not been evaluated in Japanese patients.Methods: Based on the ISN/RPS classification, only patients diagnosed with lupus nephritis class III or IV were included. The remission of proteinuria 12 months after diagnosis, as well as the clinicopathological features at diagnosis, on renal outcomes was examined retrospectively. Renal progression was defined as a 50% decrease in the estimated glomerular filtration rate or the development of end-stage renal disease.Results: This study included 82 Japanese patients with a median follow-up period of seven years. Although all patients received intensive induction therapy, 15 patients (18%) showed progression. Proteinuric remission 12 months after diagnosis predicted a good renal outcome by multivariate analysis. A receiver-operating characteristic analysis of 38 patients whose quantitative urinary protein excretion levels at 12 months were available for analysis showed that a cut-off value of 0.8 g/day predicted renal progression most effectively. Neither the renal function nor proteinuria level at diagnosis were associated with the renal outcomes.Conclusion: In Japanese patients with lupus nephritis class III or IV, proteinuria levels after 12 months under intensive therapy predicted renal outcomes more accurately than did factors identified at diagnosis.

Clinical and Pathological Characteristics of Elderly Japanese Patients with IgA Vasculitis with Nephritis: A Case Series.

Objective This case series aimed to identify the clinical and pathological characteristics of elderly patients (≥60 years) with biopsy-proven IgA vasculitis with nephritis (IgAVN). Methods The clinical and pathological presentation and treatment outcomes were compared between two groups. Patients Patients with IgAVN who were ≥19 years old at the time of their renal biopsy were divided into elderly (≥60 years) and adult (19-59 years) groups. Results Of the 23 patients in our study, 13 were elderly. In the elderly group, the median age at the diagnosis was 68 years (range, 60-85 years), with a median follow-up period of 15 months (range, 3-80 months). Twelve elderly patients had comorbidities, including hypertension, diabetes mellitus, chronic kidney disease, cardiovascular disease, and malignancies. A decrease in the estimated glomerular filtration rate, as well as massive proteinuria and rapidly progressive nephritic syndrome, were more frequent in the elderly group than in the adult group. Furthermore, renal pathological changes, including cellular or fibrocellular crescents, interstitial fibrosis, tubular atrophy, and arteriosclerosis, were more severe among elderly patients than adult patients. All elderly patients were treated with glucocorticoids and had no incidence of end-stage renal disease at the final follow-up; in addition, nine elderly patients had reduced proteinuria with a preserved renal function. Adverse events, including infection, diabetes mellitus, and vascular disorders, were identified in nine patients. Three elderly patients died from severe infections. Conclusion IgAVN in elderly patients is characterized by severe renal involvement. Elderly patients are at higher risk than adults for treatment-related adverse events.

Global polysome analysis of normal and injured podocytes.

Podocyte injury is a key event for progressive renal failure. We have previously established a mouse model of inducible podocyte injury (NEP25) that progressively develops glomerulosclerosis after immunotoxin injection. We performed polysome analysis of intact and injured podocytes utilizing the NEP25 and RiboTag transgenic mice, in which a hemagglutinin tag is attached to ribosomal protein L22 selectively in podocytes. Podocyte-specific polysomes were successfully obtained by immunoprecipitation with an antihemagglutinin antibody from glomerular homogenate and analyzed using a microarray. Compared with glomerular cells, 353 genes were highly expressed and enriched in podocytes; these included important podocyte genes and also heretofore uncharacterized genes, such as Dach1 and Foxd2. Podocyte injury by immunotoxin induced many genes to be upregulated, including inflammation-related genes despite no infiltration of inflammatory cells in the glomeruli. MafF and Egr-1, which structurally have the potential to antagonize MafB and WT1, respectively, were rapidly and markedly increased in injured podocytes before MafB and WT1 were decreased. We demonstrated that Maff and Egr1 knockdown increased the MafB targets Nphs2 and Ptpro and the WT1 targets Ptpro, Nxph3, and Sulf1, respectively. This indicates that upregulated MafF and Egr-1 may promote deterioration of podocytes by antagonizing MafB and WT1. Our systematic microarray study of the heretofore undescribed behavior of podocyte genes may open new insights into the understanding of podocyte pathophysiology.

Volume Ratio of Glomerular Tufts to Bowman Capsules and Renal Outcomes in Nephrosclerosis.

BACKGROUND: The concomitant appearance of glomerular collapse and enlargement is characteristic of the histological findings in nephrosclerosis. However, no previous study quantitatively examined the clinicopathological significance of this feature in patients with biopsy-proven nephrosclerosis. METHODS: Renal biopsy specimens and follow-up data from nephrosclerosis patients with estimated glomerular filtration rates >30 ml/min/1.73 m2 at diagnosis were retrospectively reviewed. Mean volumes for glomerular tufts (GV) and Bowman capsules (BV) were separately calculated, based on the measurement of all areas of glomerular tufts and Bowman capsules in a cross-section of biopsy specimens. The G/B ratio was defined as the ratio of GV to BV. The doubling of serum creatinine levels (DSC) and the initiation of renal replacement therapies (end-stage renal disease (ESRD)) were examined as renal outcome indices. RESULTS: A total of 67 patients with biopsy-proven nephrosclerosis were included. Clinicopathological findings at biopsy, other than GV, were comparable among all patients, irrespective of G/B ratio. Overall, 25 patients (37%) developed DSC and 9 (13%) developed ESRD during the median observation periods of 7.8 and 8.5 years, respectively. Renal survival curve analyses indicated a significantly worse prognosis for patients with a low G/B ratio, as compared with those with a high G/B ratio. Cox hazard analyses for DSC identified low G/B ratio as a significant predictor, but not low GV or BV. CONCLUSIONS: These results suggest that the quantitative evaluation of G/B ratio may detect subtle abnormalities in the glomerulus, indicating the subsequent renal outcomes of nephrosclerosis patients.

A grading system that predicts the risk of dialysis induction in IgA nephropathy patients based on the combination of the clinical and histological severity.

Histological classification is essential in the clinical management of immunoglobulin A nephropathy (IgAN). However, there are limitations in predicting the prognosis of IgAN based on histological information alone, which suggests the need for better prognostic models. Therefore, we defined a prognostic model by combining the grade of clinical severity with the histological grading system by the following processes. We included 270 patients and explored the clinical variables associated with progression to end-stage renal disease (ESRD). Then, we created a predictive clinical grading system and defined the risk grades for dialysis induction by a combination of the clinical grade (CG) and the histological grade (HG). A logistic regression analysis revealed that the 24-h urinary protein excretion (UPE) and the estimated glomerular filtration rate (eGFR) were significant independent variables. We selected UPE of 0.5 g/day and eGFR of 60 ml/min/1.73 m2 as the threshold values for the classification of CG. The risk of progression to ESRD of patients with CG II and III was significantly higher than that of patients with CG I. The patients were then re-classified into nine compartments based on the combination of CG and HG. Furthermore, the nine compartments were grouped into four risk groups. The risk of ESRD in the moderate, high, and super-high-risk groups was significantly higher than that in the low-risk group. Herein, we are giving a detailed description of our grading system for IgA nephropathy that predicted the risk of dialysis based on the combination of CG and HG.