Features Of Renal Biopsies Research Articles

Predictors of glomerular IgA immunostaining patterns and disease progression in IgA nephropathy patients; a 13-year study of clinical and morphological features of renal biopsies

Introduction: IgA nephropathy (IgAN) is a common primary glomerulonephritis with highly heterogeneous clinical and histopathological features. The MEST-C scoring system has been developed to improve prognostic assessment but lacks elements related to immunostaining study. Objectives: This study aimed to investigate the association between the immunofluorescence (IF) deposits’ patterns of IgA (mesangiocapillary versus pure mesangial) with demographic, clinical, biochemical, and morphological parameters of MEST-C classification in IgAN patients. Patients and Methods: This retrospective, cross-sectional study was conducted on 268 biopsy-proven cases of IgAN from July 2009 to July 2022 at a single laboratory in Isfahan in Iran. The demographic, clinical, and laboratory data including age, gender, serum creatinine, and proteinuria were collected from the biopsy request forms. The morphological parameters of MEST-C classification and IF study patterns were collected from the biopsy reports. Results: The average age of all patients was 37.7 ± 13.47 years, with 67% being males. The mean serum creatinine and proteinuria levels were 1.43 mg/dL and 1730.94 mg/day, respectively. MEST-C score analysis revealed that 171 patients (63.8%) had mesangial expansion (M1), while 105 patients (39.2%) exhibited endocapillary hypercellularity (E1). Additionally, segmental glomerulosclerosis (S1) and tubular atrophy/interstitial fibrosis (T1 and T2) was observed in 160 biopsy samples (59.7%). Moreover, crescent (C) formation was noted in 76 (28.4%) of biopsies. Data analysis using univariate logistic regression demonstrated that E, T, and C on morphology, complement C3, IgG, IgM deposits on IF, and the total MEST score were all associated with an increased risk for mesangiocapillary deposits of IgA. However, using the multivariate method, the results indicated that only the total MEST score (OR: 2.4), presence of crescent (OR: 3.22), presence of endocapillary hypercellularity (OR: 4.86), tubular atrophy/interstitial fibrosis grade II (OR: 34.4), and IgG deposition (OR: 3.37) were independent risk factors for mesangiocapillary deposits of IgA. Conclusion: The total MEST score is significantly higher in mesangiocapillary patterns. Furthermore, the presence of E1, T2, and C1-2 morphological parameters of the updated Oxford classification in renal biopsies are independent risk factors for IgA mesangiocapillary deposits. Hyperactivation of immunoglobulins and the complement system appears to contribute to mesangial-capillary proliferation.

Podocyte Infolding Glomerulopathy: A Special Morphology of Podocyte Injury Caused by Heterogeneous Diseases

Podocyte infolding glomerulopathy (PIG) is a newly recognized rare glomerular injury. The clinical significance and mechanism of this injury pattern remains unclear. We conducted a retrospective study of renal biopsies from January 2018 to December 2020 in Kingmed Diagnostics. The renal biopsy features and clinical data were reviewed. Laser scanning microdissection and mass spectrometry (LMD/MS) was conducted to analyze the potential mechanism. A total of 116 (0.092%) out of 126,086 biopsies were diagnosed as PIG during the period. Of these, 89 (76.7%) cases were found to have PIG coexisting with immune-complex associated glomerulonephritis (IC-PIG) whereas 27 (23.3%) were identified as isolated PIG without immunoglobulin or complement deposition. Systemic lupus erythematosus (SLE), especially with membranous lupus nephritis (LN), was diagnosed in most (70.8%) IC-PIG cases. Of the isolated PIG cases, 51.9% had no known underlying conditions; however, a relatively high positive rate (42.1%) of antinuclear antibody (ANA) was detected. Nearly half (47.5%) of the patients presented with nephrotic syndrome (NS). PIG grade was associated with proteinuria in isolated PIG (P= 0.035). LMD/MS revealed dysregulated cytoskeletal protein α-actinin4 (ACTN4) and tubulin beta-4 chain in PIG compared with normal donor kidney and minimal change disease (MCD). The displacement of ACTN4 into the glomerular basement membrane (GBM) was confirmed by the confocal microscope. PIG is a rare podocyte injury that can exist alone without underlying disease or be concurrent with various diseases, especially SLE. Podocyte cytoskeletal protein ACTN4 and tubulin beta-4 chain were dysregulated, which may be involved in the mechanism of PIG.

Primary Hyperoxaluria Type 1: Clinical, Paraclinical, and Evolutionary Aspects in Adults from One Nephrology Center.

Primary hyperoxaluria type 1 (PH1) is a rare and inherited condition of urolithiasis. The aim of our study was to analyze clinical, paraclinical, and evolutionary aspects of PH1 in adult patients in our Nephrology department. We conducted a retrospective single-center study between 1990 and 2021. We collected patients followed for PH1 confirmed by genetic study and/or histopathological features of renal biopsy and morphoconstitutional analysis of the calculi. There were 25 patients with a gender ratio of 1.78. The median age at onset of symptoms was 18 years. A delay in diagnosis more than 10 years was noted in 13 cases. The genetic study found the I244T mutation in 17 cases and 33-34 InsC in 4 cases. A kidney biopsy was performed in 5 cases, on a native kidney in 4 cases and on a graft biopsy in one case. The analysis of calculi was done in 10 cases showing type Ic in 2 cases. After a median follow-up of 13 years (1 year-42 years), 14 patients progressed to end-stage chronic renal failure (ESRD). The univariate study demonstrated a remarkable association with progression to ESRD in our population (44% vs. 56%) RR = 13.32 (adjusted ORs (95% CI): 2.82-62.79) (p < 0.01). Progression to ESRD was frequent in our series. Early diagnosis and adequate management can delay such an evolution.

Renal toxicity caused by diethylene glycol: an overview.

Diethylene glycol (DEG) is nephrotoxic, potentially resulting in high morbidity and mortality. Its main nephrotoxic by-product is diglycolic acid (DGA). This narrative overview summarizes selected literature with a focus on clinical findings, pathophysiology, diagnosis including morphological features of renal biopsies, and management. The kidney injury in DEG poisoning is secondary to proximal tubular necrosis caused by DGA. Marked vacuolization and edema of epithelial cells obstruct the lumen, reducing urine flow and, consequently, resulting in anuria and uremia. The clinical alterations due to DEG poisoning are dose-dependent. Patients may present with gastrointestinal symptoms and anion gap metabolic acidosis, followed by renal failure, and, later, encephalopathy and neuropathy. Although this three-phase pattern has been described, signs and symptoms may be overlapping. Data about DEG intoxication is scarce. Sometimes the diagnosis is challenging. The management includes supportive care, gastric decontamination, correction of acid-base disorders, and hemodialysis. The understanding of the metabolic processes related to DEG poisoning may contribute to its management, preventing death, serious sequels, or irreversible lesions.

One-third of patients with lupus nephritis classified as complete responders continue to accrue progressive renal damage despite resolution of proteinuria

ObjectiveTreatment response in lupus nephritis (LN) is defined based on proteinuria, yet protocol kidney biopsy studies have shown that patients with lupus can have active nephritis in the absence of...

Correlation between Pathological Findings and the Usefulness of Clinical Guidelines for the Treatment of ANCA-Positive RPGN: A Retrospective Analysis.

The physical condition of patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated rapidly progressive glomerulonephritis (RPGN) is at times too critical for physicians to undertake a renal biopsy. In such cases, physicians need to start treatments without determining the pathological features of the disease. However, the prevalent clinical practice guidelines for ANCA-associated RPGN in Japan do not necessitate the pathological findings in a renal biopsy for determining first-line treatments. The aim of this study was to assess the correlation between the pathological findings and the clinical guideline-based treatments of ANCA-associated RPGN. We investigated clinical and pathological features of patients who were admitted to our hospital to undergo a percutaneous renal biopsy for the diagnosis of ANCA-associated RPGN and were treated per clinical practice guidelines formulated by the Japanese Society of Nephrology. We divided patients into the following three groups according to their treatments: (a) group A, oral intake of prednisolone (PSL) only; (b) group B, methylprednisolone (mPSL) pulse therapy followed by oral intake of PSL; and (c) group C, mPSL pulse therapy followed by oral intake of PSL and the administration of immunosuppressive agents. We compared the crescent formation ratio (CFR) in glomeruli in each treatment group. The median CFR (%; ±standard deviation [SD]) in group A (8.7%±7.7%) was significantly lower than that in groups B (30.2%±15.7%) and C (71.3%±25.5%); group A vs. group B, P<0.05; group A vs. group C, P<0.0001. In addition, the median CFR in group B was significantly lower than that in group C (P<0.01). The median serum creatinine levels (mg/dL; ±SD) in both groups A (2.03±0.96 mg/dL) and B (1.90±0.86 mg/dL) were significantly lower than that in group C (4.30±1.63 mg/dL); group A vs. group C, P<0.01; group B vs. group C, P<0.01. No significant difference was observed in the serum levels of C-reactive protein and ANCA in each treatment group. Although the pathological features of renal biopsy are not included in the factors in the clinical scores described in the guidelines, guideline-based treatments reflected the severity of the crescent formation in each treatment group. This study suggests that the clinical practice guidelines for ANCA-associated RPGN used in Japan facilitate physicians to determine disease management in patients presenting difficulties in undergoing a renal biopsy.

Revisiting renal amyloidosis with clinicopathological characteristics, grading, and scoring: A single-institutional experience.

INTRODUCTION:Kidney involvement is a major cause of mortality in systemic amyloidosis. Glomerulus is the most common site of deposition in renal amyloidosis, and nephrotic syndrome is the most common presentation. Distinction between AA and AL is done using immunofluorescence (IF) and immunohistochemistry (IHC). Renal biopsy helps in diagnosis and also predicting the clinical course by applying scoring and grading to the biopsy findings.MATERIALS AND METHODS:The study includes all cases of biopsy-proven renal amyloidosis from January 2008 to May 2017. Light microscopic analysis; Congo red with polarization; IF; IHC for Amyloid A, kappa, and lambda; and bone marrow evaluation were done. Classification of glomerular amyloid deposition and scoring and grading are done as per the guidelines of Sen S et al.RESULTS:There are 40 cases of biopsy-proven renal amyloidosis with 12 primary and 23 secondary cases. Mean age at presentation was 42.5 years. Edema was the most common presenting feature. Secondary amyloidosis cases were predominant. Tuberculosis was the most common secondary cause. Multiple myeloma was detected in four primary cases. Grading of renal biopsy features showed a good correlation with the class of glomerular involvement.CONCLUSION:Clinical history, IF, and IHC are essential in amyloid typing. Grading helps provide a subtle guide regarding the severity of disease in the background of a wide range of morphological features and biochemical values. Typing of amyloid is also essential for choosing the appropriate treatment.

Concomitant urothelial cancer and renal tuberculosis.

We report a case of coexisting urothelial cancer and renal tuberculosis in the same kidney. The patient is a 72-year-old female with a remote history of treated pulmonary tuberculosis who presented with haematuria, initial investigation of which elucidated no definitive cause. Almost 1 year later, a diagnosis of metastatic urinary tract cancer was made. The patient received chemotherapy for advanced collecting duct type renal cell carcinoma, based on histological features of renal biopsy. Subsequent confirmatory immunostains however led to a revised diagnosis of urothelial cancer, necessitating a change in chemotherapy regimen. A diagnosis of ipsilateral renal tuberculosis was made based on TB-PCR testing of renal biopsy tissue and anti-TB therapy was coadministered with chemotherapy. The patient died 9 months after diagnosis of metastatic urothelial cancer.

Renal histology in pauci-immune rapidly progressive glomerulonephritis: 8-year retrospective study

The need to perform reporting of renal biopsies of antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides in a more uniform manner required relook at our eight-year data. To document detailed renal histopathology of pauci-immune rapidly progressive glomerulonephritis (RPGN) and also to seek any significant differences in renal histology of C-ANCA-positive, P-ANCA-positive, and ANCA-negative patients. A detailed analysis of the histopathologic features of renal biopsies of 48 patients in whom a diagnosis of pauci-immune glomerulonephritis was concluded on renal biopsy and who presented clinically as rapidly progressive renal failure was done. One-way ANOVA and Pearson Chi square tests. Compared with ANCA +ve patients, the ANCA -ve patients were much younger (46.85 ± 16.12 years vs 34.28±15.94 years). No significant differences were found between renal lesions of C-ANCA, P-ANCA, and ANCA-negative patients, except for diffuse tubular atrophy which was more severe and more frequently present with P-ANCA positivity (P value=0.013). Pauci-immune RPGN (irrespective of ANCA status) is a relatively rare disorder in patients who are undergoing the renal biopsy at our institute, constituting 2% of all renal biopsies submitted. It is mandatory to have ANCA serology status during reporting of a kidney biopsy showing pauci-immune crescentic or necrotizing glomerulonephritis. Also, if a uniform reporting strategy is followed throughout the country, the studies from this vast country will be comparable.

Toll-like receptor 4 expression is increased in circulating mononuclear cells of patients with immunoglobulin A nephropathy

We investigated Toll-like receptors (TLR-3, -4 and -7) expression in circulating mononuclear cells of patients with immunoglobulin A nephropathy (IgAN), a disease with debated relationships with mucosal immunity. TLR-4 expression (detected by fluorescence activated cell sorter) and mRNA transcriptional levels (Taqman) were significantly higher in patients with IgAN than in healthy controls (P = 0.00200 and P = 0.0200). TLR-3 and TLR-7 were not modified significantly. In IgAN patients proteinuria was correlated significantly with TLR-4 expression (P = 0.0312). In a group of nephrotic syndromes, TLR-3, -4 and -7 expression was similar to healthy controls. A significant difference in TLR-4 expression and mRNA levels was found between very active IgAN patients (proteinuria > 1 g/1.73 m(2)/day in association with severe microscopic haematuria) and inactive patients (proteinuria < 0.5 g/1.73 m(2)/day, with absent or minimal haematuria). No correlation with levels of aberrantly glycosylated IgA1, age, renal biopsy features or therapy was found. This study shows for the first time an up-regulation of TLR-4 in circulating mononuclear cells of patients with IgAN, particularly in association with proteinuria and heavy microscopic haematuria.

Ponticelli regimen and nephrotic syndrome

Sir, We read the article of Das et al.[1] with interest; it raised few questions that beg answers. Both in children and adults with steroid resistant minimal change disease (MCD) and focal segmental glomerulo sclerosis (FSGS), cyclosporine is the preferred choice.[2] Cytotoxic drug (cyclophosphamide) is indicated in frequent relapsing and/ or steroid dependent/toxicity group of MCD pediatric patients. The article was a mixture of frequent relapsers and steroid resistant nephrotic syndrome (SRNS). It is possible that the patients who improved with this protocol were only frequent relapsers, not affected with SRNS. Presuming that only cyclophosphamide (cytotoxic drug) is sufficient, addition of high dose of steroid adds to the steroid toxicity. The addition of prednisone to the cytotoxic drug may not improve the efficacy of the regimen, but it allows the patient for high fluid intake to protect against the cystitis. In such a case, the dose of steroid is tapered once remission is achieved.[3] The authors were not explicit about the use of the terms, ‘frequent relapsers’ and ‘steroid resistant’ in the context of membranoproliferative glomerulonephritis and IgA nephropathy. IgA nephropathy is treated when proteinuria >1 g/24 h with preserved renal function with steroid for six months and with progressive renal failure (serum creatinine <2.84 mg/dl), a cytotoxic agent is added. The treatment in the latter group is at least for two years.[4] It is surprising that the lone IgA nephropathy with FR (sic) and renal impairment achieved remission and improvement in renal function at the end of six months. Results in fact did not present clinical and laboratory features of each group of the disease. With expanding armamentarium to treat nephrotic syndromes, based on it etiology, proteinuria, renal impairment, renal biopsy features and individual merit, the authors surprisingly presented a unifying concept of a common treatment to all nephrotic syndromes, irrespective of its etiology. Is there a message, that the renal biopsy is, now, redundant; treat all with steroids, but if there is no response, use this protocol.[1] The definition used for ‘renal failure’ in the article was persistent doubling of plasma creatinine over baseline value but the highest serum creatinine, mentioned only in Table 4, was only 1.12 + 0.58 mg/dl. In Table 3, another term ‘renal insufficiency’ was used, but it was not defined in the article.

Clinicopathologic analysis of renal biopsies after haematopoietic stem cell transplantation

The ever-growing number and increasing survival of haematopoietic stem cell transplantation (HSCT) allow better recognition of its associated renal injuries. We aimed to study the clinicopathologic features of renal biopsies after HSCT by reviewing 13 percutaneous renal biopsies in our institute (Queen Mary Hospital). A retrospective clinicopathologic study of all renal biopsies archived to the Department of Pathology, Queen Mary Hospital during the period January 1999 to December 2006 was performed. Biopsies from patients with HSCT were selected. Clinical data on presentation and follow up were retrieved from hospital records and physicians. In the 8-year period, a total of 2233 native renal biopsies were archived. Thirteen renal biopsies were selected from 12 patients with HSCT (11 allogeneic, one autologous). All but one patient were male. The age at renal biopsy ranged from 7 to 63 years (median: 32 years). The median interval of renal biopsy after HSCT was 24 months (range 1-134 months). Evidence of graft-versus-host disease was found in nine patients. The most common presentation was significant proteinuria (10 cases) and renal impairment (eight cases). The predominant histological changes were membranous glomerulonephritis (n = 4) and thrombotic microangiopathy (n = 4). One case of focal segmental glomerulosclerosis, IgA nephropathy, minimal change disease, acute tubular necrosis and hypertensive nephrosclerosis were also recorded. Four of our patients died at 0-11 months after renal biopsy. Of the remaining eight patients with a mean follow up of 43.6 months (range, 10-98 months), chronic renal impairment were found in three (37.5%) patients and significant proteinuria also persisted in three. One patient had cytogenetic evidence of relapse of underlying haematological malignancy after HSCT. Among the various renal lesions after HSCT, membranous glomerulonephritis and thrombotic microangiopathy were the most common. Mechanisms of renal injury varied from graft-versus-host disease-associated immune complex deposition to non-immune complex injury on endothelial cells, glomerular epithelial cells and tubular epithelium. Pathologists and clinicians should attend to the histological and temporal heterogeneity of renal injury when managing patients after HSCT.

Abnormally thin glomerular basement membranes associated with hematuria, proteinuria or renal failure in adults.

Clinical and pathologic findings are described in 14 patients whose main abnormality was an excessively thin glomerular basement membrane (GBM). The subjects were aged 11-51 years, the majority males: most were referred because of hematuria, but proteinuria was the main problem in 2, while hypertension or renal functional impairment was found in several, and 1 was in end-stage renal failure. A history of apparently similar renal symptoms was obtained in another 3 family members. In addition to GBM abnormalities, renal biopsy features included a slight mesangial matrix increase, occasional mesangial cell excess and often appreciable pedicel effacement. There were scanty electron-dense deposits. The mean thickness of the GBM varied from 206 to 301 nm, whereas in IgA nephropathy patients used as controls it was 356-464 nm. It is concluded that some of the lesions in adults are 'benign', and some progressive. 'Thin membrane nephropathy' is comparatively common among patients seen by the authors, and it is suggested that awareness of this condition will result more often in its recognition.

The use of local allograft irradiation following renal transplantation

Over a 10 year period, 67 recipients of 71 renal allografts received graft irradiation following the diagnosis of rejection. The majority of kidneys were treated with a total dose of 600 rad, 150 rad per fraction, in 4 daily fractions. Fifty-three kidneys were irradiated following the failure of standard systemic immunosuppression and maximally tolerated antirejection measures (pulse high dose steroids, Actinomycin, ATG) to reverse an episode of acute rejection. Seven of these patients (13%) had greater than a 50% improvement in serum creatinine (Cr) 1 week following completion of the irradiation. Twenty-two (42%) of these allografts were noted to have stable (i.e. no deterioration) or improved function 1 month following the treatment with irradiation. Eleven (21%) of these allografts maintained function 1 year following transplantation. There were 10 patients whose allografts were irradiated because of renal dysfunction in a clinical setting which did not permit the administration of further immunosuppression, i.e., infection or hematologic dyscrasias. Three of these patients (30%) had greater than a 50% improvement in serum Cr 1 week following completion of the irradiation. Nine (90%) of these allografts had stable or improved function 1 month following the treatment with irradiation. Biopsies were obtained of 41 allografts. Of the 24 renal allografts with predominantly cellular rejection, 10 (42%) had the process reversed or stabilized at 1 month following irradiation. Five (21%) of these allografts were functioning at I year following irradiation. Rejection was reversed or stabilized in 6 of 17 (35%) allografts at 1 month when the histologic features of renal biopsy suggested predominantly vascular rejection. One (6%) of these allografts was functioning at 1 year following transplantation. Local graft irradiation has helped maintain a limited number of allografts in patients whose rejection has failed to respond to systemic immunosuppression. Irradiation may also benefit patients with ongoing rejection in whom further systemic immunosuppression is contra-indicated.

Early Pathologic Features of Hereditary Nephritis: A Clinicopathologic Correlation

The histologic, immunofluoresence and electron microscopic features of renal biopsies from twelve patients having hereditary nephritis were examined and correlated with the clinical data. In ten patients with normal renal function, light microscopy showed similar but nonspecific glomerular abnormalities consisting of mild focal and segmental hypercellularity and thickening of capillary walls. Biopsies from two patients with azotemia had diffuse lesions of the glomeruli and associated interstitial fibrosis. There were no characteristic findings on immunofluorescence. Electron microscopy revealed alterations in thickness and density of the glomerular capillary basal lamina in all patients. However, lamellation of the basement membrane and the presence of electron dense granules were present only in the two patients with renal functional impairment. These findings support the view that hereditary nephritis is a form of glomerular disease in which ultrastructural changes in the basal lamina of glomerular capillaries are the earliest and most consistent lesions. However, the morphologic spectrum of these ultrastructural abnormalities is broader than previously recognized.

Histologic features of renal biopsies from patients with essential hypertension and from the aged.

In order to clarify the vascular changes involved in the kidneys in essential hypertension, a histological study was performed on the renal biopsy materials obtained from 15 patients with juvenile form of essential hypertension, 30 elderly patients with essential hypertension, and 10 ordinary aged persons without hypertension, who admitted in the third medical clinic of Kyoto University Hospital between 1959 and 1963. It was found that the renal vascular disease in essential hypertension was predominantly in the small arteries and arterioles, especially in the media of arterioles, and included spasm, hypertrophy with or without vacuolation, hyperplasia, degeneration, atrophy with fibrosis and fibrinoid degeneration or necrosis of the medial smooth muscle. Intimal proliferation appeared to follow the changes in the media, while in the ordinary aged persons intimal sclerosis occurred from larger arteries with milder degree of severity. These flndings suggest that fundamental importance in the development of systemic hypertension should be attached to the problems on the contraction of the smooth muscle cells of the peripheral small arteries and arterioles.