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A woman in her 50s was referred to nephrology clinic due to progressive chronic kidney disease. She exhibited features of proximal renal tubulopathy, namely Fanconi syndrome, including normoglycaemic glycosuria, normal anion gap metabolic acidosis, and intermittent hypouricaemia and hypophosphataemia. Kidney biopsy showed tubulointerstitial inflammation and focal chronic damage. In addition, antimitochondrial antibodies were present and she had abnormal liver blood tests. A unifying diagnosis of primary biliary cholangitis with an associated renal tubulopathy and interstitial nephritis was made. She was commenced on sodium bicarbonate, ursodeoxycholic acid and oral prednisolone, leading to an improvement in liver biochemistry. Kidney function was stabilised, but a sustained improvement was not seen. This case acts as a reminder of the rare association of tubulointerstitial nephritis and Fanconi syndrome with primary biliary cholangitis, which may be an under-recognised phenotype.

A teenage girl presented with fever after aspirin use. Examination revealed no organ-specific symptoms. The serum creatinine level and urine analysis findings were normal. The drug lymphocyte stimulation test was positive for aspirin. Diffusion-weighted magnetic resonance imaging (DW-MRI) revealed hyperintensity in both kidneys although serum creatinine was only mildly elevated. A subsequent kidney biopsy confirmed acute interstitial nephritis (AIN). She later developed uveitis and the final diagnosis was tubulointerstitial nephritis and uveitis (TINU) syndrome, possibly triggered by aspirin, requiring systemic and topical corticosteroid therapies. TINU syndrome should be considered in young patients with fever of unknown origin and a history of nonsteroidal anti-inflammatory drug use. This is the first reported case suggesting the usefulness of DW-MRI, which is safe for children without exposure to ionising radiation, in detecting early-stage AIN before apparent kidney impairment.

The combination of immune-checkpoint inhibitors (ICI) and platinum-pemetrexed chemotherapy (CT) in first-line setting improved survival outcomes of advanced non-small cell lung cancer (NSCLC) patients. Among the various adverse events, renal toxicity can be a relevant safety issue.We conducted a single-center, observational retrospective study including consecutive patients treated with upfront CT-ICI for advanced nonsquamous NSCLC to investigate incidence and clinical characteristics of acute kidney injury (AKI) using 'Acute Kidney Injury Working Group of Kidney Disease: Improving Global Outcomes' (KDIGO) definition.A total of 89 patients received a first-line CT/ICI. The median age was 69 years. 60.7 % were male, and 87.6 % had an ECOG PS of 0-1. 92.1 % had a baseline glomerular filtration rate of at least 60 ml/min. According to KDIGO criteria, 25 (28 %) patients developed AKI. Considering risk factors for AKI onset, patients receiving10 cycles of CT/ICI were more likely to experience AKI (p 0.001). No other associations were found with other variables, including concomitant medications. Any component of the treatment was discontinued (pemetrexed pembrolizumab or both) in 10 (40 %) patients, and 9 patients (36 %) were addressed to nephrological consultation. These patients had higher mean creatinine variation from baseline (1 vs 0.6 mg/dl, p = 0.025) and creatine level (1.8 vs 1.4 mg/dl, p = 0.015), but lower eGFR (35.7 vs 54.2 ml/min, p = 0.011) in comparison to patients not addressed. No patients had microscopic hematuria or pyuria, but mild proteinuria (0.8 g/24 h) was found in 4 patients. A renal biopsy was performed on 3 patients, revealing acute tubule interstitial nephritis (ATIN), karyomegalic interstitial nephritis, and acute tubular necrosis (ATN).Renal toxicity represents a challenging adverse event that could negatively impact outcomes of metastatic nonsquamous NSCLC patients receiving CT/ICI demanding a multidisciplinary approach.

A 39-year-old woman was hospitalized for nephrotic syndrome. Laboratory test results showed increased serum creatinine levels and urinary excretions of beta-2-microglobulin, and N-acetyl-beta-D-glucosaminidase. A renal biopsy revealed collapsing focal segmental glomerulosclerosis (FSGS) and acute interstitial nephritis. Despite treatment with pulse steroid followed by oral high-dose glucocorticoids and cyclosporines, heavy proteinuria persisted. After low-density lipoprotein apheresis (LDL-A) therapy was initiated, her proteinuria gradually decreased, leading to complete remission. A repeat renal biopsy after treatment revealed no collapsing glomeruli. Immediate LDL-A should be performed to treat cases of collapsing FSGS poorly responding to other treatments.

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.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.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.This largest case series study of the biopsy-proven TIN in Japan provides detailed information regarding both etiology-based clinicopathological properties and kidney outcomes.

Immune check point inhibitors (ICIs) are now increasingly used for cancer therapy. At the same time, by activating the immune system, ICIs induce unique side effects, termed immune-related adverse events (irAEs). Renal irAEs, although uncommon, result in acute tubulointerstitial nephritis. Recently, because of an increase in ICI administration, renal irAEs, including glomerulonephritis, are being increasingly reported. A 69-year-old man presented with nephrotic syndrome after use of the ICI nivolumab. He underwent renal biopsy and was diagnosed with membranous nephropathy (MN) without acute tubulointerstitial nephritis. Immunofluorescence staining was negative for IgG4 and phospholipase A2 receptor (PLA2R), suggesting a malignancy-associated pattern. Oral glucocorticoid therapy was started as the standard treatment for irAEs, which resulted in complete remission of the nephrotic syndrome in 20 months. We suggest his MN was induced or accelerated by immune activation due to nivolumab. It means that ICIs possibly induce not only acute tubulointerstitial nephritis but also nephrotic syndrome due to MN as renal irAEs which is treatable with glucocorticoid.

Background Tubulointerstitial nephritis with uveitis syndrome is a rare disease affecting mainly children and young women. Tubulointerstitial nephritis with uveitis is a diagnosis of exclusion, requiring a high degree of clinical suspicion. Studies report recent infections or certain drugs as precipitating factors of a lymphocytic oculorenal immune response. The prognosis is usually favorable with topical and systemic corticosteroid therapy. Case presentation We report a literature review and the case of a 14-year-old white girl, who presented to the ophthalmology department with features of one-sided uveitis. Upon transfer of patient to nephrological care, diagnostic work-up revealed renal involvement. Renal biopsy showed a mixed-cell and granulomatous tubulointerstitial nephritis with some noncaseating granulomas, leading to a diagnosis of tubulointerstitial nephritis with uveitis syndrome. With topical ocular and systemic corticosteroid therapy, the patients’ condition improved over several weeks. Conclusions Our case highlights the importance of early recognition and treatment of this syndrome, where cross-specialty care typically leads to a favorable outcome.

Background Histological findings of kidney involvement have been rarely reported in pediatric patients with SARS-CoV-2 infection. Here, we describe clinical, laboratory, and histological findings of two pediatric cases with almost exclusive kidney involvement by SARS-CoV-2. Results A 10-year-old girl with IgA vasculitis nephritis underwent kidney biopsy, showing diffuse and segmental mesangial-proliferative glomerulonephritis, and steroid therapy was initiated. After the worsening of the clinical picture, including an atypical skin rash, she was diagnosed with SARS-CoV-2. The re-evaluation of initial biopsy showed cytoplasmatic blebs and virus-like particles in tubular cells at electron microscopy. Despite SARS-CoV-2 clearance and the intensification of immunosuppression, no improvement was observed. A second kidney biopsy showed a crescentic glomerulonephritis with sclerosis, while virus-like particles were no longer evident. The second patient was a 12-year-old girl with a 3-week history of weakness and weight loss. Rhinitis was reported the month before. No medications were being taken. Blood and urine analysis revealed elevated serum creatinine, hypouricemia, low molecular weight proteinuria, and glycosuria. A high SARS-CoV-2-IgG titre was detected. Kidney biopsy showed acute tubular-interstitial nephritis. Steroid therapy was started with a complete resolution of kidney involvement. Conclusion We can speculate that in both cases SARS-CoV-2 played a major role as inflammatory trigger of the kidney damage. Therefore, we suggest investigating the potential kidney damage by SARS-CoV-2 in children. Moreover, SARS-CoV-2 can be included among infectious agents responsible for pediatric acute tubular interstitial nephritis.

Kidney biopsy is the most important tool for diagnosing kidney disease and can be helpful in determining treatment and prognosis. Pathological spectra vary by country, region, race, sex, and age. We are the first to investigate the pathological spectrum of biopsy-proven kidney disease in Gyeongnam province of South Korea. We retrospectively analyzed 631 patients who underwent a kidney biopsy between 2013 and 2019 at Gyeongsang National University Hospital. The mean age of the 631 patients was 51.5 ± 18.1 years, and 361 patients (57.2%) were male. The mean estimated glomerular filtration rate by serum creatinine (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) was 68.0 ± 45.7 mL/min/1.73 m2. The mean systolic blood pressure was higher in 2017, 2018, and 2019 than in 2013 (P = .002). Hypertension (47.4%) was the most common comorbid disease, followed by diabetes (18.2%) and dyslipidemia (10.9%). Common clinical syndromes at the time of biopsy were renal insufficiency (42.0%) and nephrotic syndrome (33.9%). The prevalence of primary and secondary glomerular disease and tubulointerstitial disease were 71.4%, 16.9%, and 5.4%, respectively. Immunoglobulin A nephropathy was the most common primary glomerular disease (34.9%). Diabetic nephropathy was the most common secondary glomerular disease, followed by lupus nephritis. Tubulointerstitial disease was underestimated, as in other reports. Our data can be a useful reference for diagnosing kidney disease and understanding the patients in our province.

Renal toxicity from immune checkpoint inhibitors (ICIs) is an increasingly recognized cause of acute kidney injury among patients with cancer. ICI-associated acute kidney injuries typically present as acute interstitial nephritis and the timing of onset is highly variable. Herein, we present a case of a patient with relapsed metastatic melanoma previously treated with pembrolizumab who developed grade 3 immune-related renal toxicity after reintroduction of the same ICI, secondary to acute interstitial nephritis with accompanying high PR3-antineutrophil cytoplasmic antibody titer. The patient improved after steroid treatment and discontinuation of pembrolizumab. This case highlights the importance of not excluding ICI-related nephrotoxicity as a possible cause of renal failure, including in those who previously tolerated ICI treatment, since it is a treatable entity.

Genes of UMOD, HNF1B, MUC1, REN and SEC61A1 were reported to be associated with autosomal dominant tubulointerstitial kidney disease (ADTKD). 48 probands and their family members (N = 27) were enrolled in this genetic screening study. A combination of methods was employed for comprehensive molecular analysis of both copy number variations (CNVs) and single nucleotide variants (SNVs). 35 probands were followed for years. The phenotype-genotype and genotype-outcome correlation were inferred from these datasets. In this cohort, 18 probands were diagnosed with ADTKD, according to Kidney Disease: Improving Global Outcomes (KDIGO) guideline. Moreover, 11 probands were diagnosed with ADTKD-UMOD, one with ADTKD-REN and one with ADTKD-HNF1B, based on molecularly confirmed pathogenic variants. The 11 UMOD variants were mainly located in codons 28 to 289 and half of the variants were found to change the cysteine amino acid. According to the follow-up data, suspected ADTKD individuals had a better prognosis compared to ADTKD individuals (p = 0.029). Individuals with a cysteine substitution in the UMOD gene appeared to have a better prognosis than individuals with other amino acid substitutions (p = 0.015).

Background Sarcoidosis is characterized by granulomatous inflammation in multiple organs. Renal involvement is rare, and granulomatous tubulointerstitial nephritis (TIN) is the predominant histologic feature. TIN is also a hallmark of tubulointerstitial nephritis and uveitis (TINU) syndrome. Diagnoses of both sarcoidosis and TINU syndrome are usually made by exclusion and by combining clinical and histological findings, and often remain misdiagnosed. The aim of this retrospective study was to determine the characteristics of renal sarcoidosis and TINU syndrome in Slovenia in the last decade (2010 - 2020). Materials and methods A thorough search of the national database of renal biopsies from January 2010 to December 2020 was performed. Inclusion criteria were TIN and a clinical history of either sarcoidosis or TINU syndrome. To compare the characteristics of our cohort with others, we also reviewed the global literature reported since 2010. Results 13 patients (9 female, 4 male) were included in our study. Indications for kidney biopsy were acute kidney injury (n = 8), acute exacerbation of chronic kidney disease (n = 4), and proteinuria (n = 1). Seven patients had clinical and histological evidence of sarcoidosis, and 6 patients were classified as having TINU syndrome. All patients were treated with corticosteroids. Of the 13 patients, 11 had improved kidney function 6 months after treatment, and proteinuria decreased in 9 patients. One patient was on dialysis at the time of diagnosis and remained so thereafter. Conclusion Renal sarcoidosis and TINU syndrome are rare but important causes of kidney injury, with a favorable long-term prognosis if properly diagnosed and treated in a timely manner.

Objects This study aimed to analyze the clinicopathological features of acute kidney disease (AKD) with renal oxalosis. Methods Data for biopsy-proven AKD with oxalosis diagnosed from Jan 2011 to Oct 2018 was collected. The underlying diseases, dietary habits, clinical and pathological characteristics of newly emerging kidney disease were analyzed. The long-term renal prognosis was observed. Results A total of 23 patients were included, comprised of 18 men and 5 women with a mean age of 51.6 ± 15.9 years. The peak Scr was 669.9 ± 299.8 μmol/L, and 95.7% of patients had stage 3 acute kidney injury (AKI). Drug-induced tubulointerstitial nephritis (TIN) was the most common cause (65.2%) of AKD, followed by severe nephrotic syndrome (17.4%). All patients had pathological changes indicating TIN, and 11 patients were complicated with the newly emerging glomerular disease (GD). The risk of oxalosis caused by increased enterogenous oxalate absorption accounted for only 26.1%, and others came from new kidney diseases. The majority (75%) of abundant (medium to severe) oxalosis occurred in patients without GD. There were no significant differences in the score for tubular injury (T-IS) and interstitial inflammation with different severities of oxalosis. Rate of Scr decrease (ΔScr%) at 2 weeks was negatively correlated with the severity of oxalosis (R = −0.542, p = 0.037), score for T-IS (R = −0.553, p = 0.033), and age (R = −0.736, p = 0.002). The decrease in Scr at 4 weeks was correlated with T-IS (R = −0.433), but had no correlation with oxalosis. Conclusions The present findings revealed that 95.7% of AKD with secondary renal oxalosis occurred in critically ill patients. AKD from tubular injury was the prominent cause. Severe oxalosis contributed to delayed early recovery of AKD.

Objectives: The determinants leading to different renal outcomes in community-acquired acute kidney injury (CA-AKI) and the influence of renal histological damage on the prognosis and recovery of CA-AKI are scarcely reported. Methods: Adult patients with CA-AKI admitted to Shanghai Changzheng Hospital with renal biopsy profiles from January 1, 2010, to December 31, 2018, were enrolled in our cohort. After 3 months of follow-up, clinical outcomes, including patient survival, dialysis requirement during hospitalization and at 3 months, CKD stage 3–5, and renal functional recovery at 3 months, were analyzed, and risk factors were identified. Results: A total of 294 patients with CA-AKI with renal pathology were identified for this cohort. Among 282 patients who survived 3 months after AKI, 59.6% completely recovered, 21.3% partially recovered, 21.3% progressed to stage 3–5 CKD without dialysis, and 17.7% maintained dialysis. Moreover, 70.4% of patients in the cohort presented with de novo intrinsic renal disease, except acute tubular necrosis or acute interstitial nephritis, on renal biopsy. In the multivariate analyses, clinical factors were more related to short-term outcomes and severity of CA-AKI, represented by mortality, in-hospital dialysis, and CRRT requirement, while pathological elements were more involved with CKD progression, including dialysis-dependent or stage 3–5 CKD, and renal function recovery at the 3-month follow-up. The detrimental influence of glomerular and arterial lesions on renal prognosis of CA-AKI was as critical as tubular and interstitial lesions. Conclusions: Clinical and pathological parameters both contribute to patient and renal outcomes after CA-AKI. The value of renal biopsy should be recognized in prognostic prediction.

Objective Drug-induced acute interstitial nephritis (DAIN) is often associated with improved outcomes, whereas some patients may still progress to chronic kidney disease (CKD). The aim of this study was to evaluate the prognosis of patients with severe DAIN requiring renal replacement therapy (RRT) at baseline, and to explore the risk factors of progression to CKD. Methods We performed a retrospective study of patients with severe DAIN confirmed by renal biopsies in our center over a 10 years period, all the patients received RRT at presentation. The clinical and pathological characteristics at baseline were recorded, and the outcomes (renal function recovered or progressed to CKD) during follow-ups were also evaluated. Univariate and multivariate logistic regression analysis were performed to identify the independent risk factors of progression to CKD. Results Seventy-two patients who met the inclusion criteria were enrolled, 13 patients (18.0%) progressed to CKD (GFR < 60 ml/min/1.73 m2) after at least 6 months of follow-up, the remaining 59 patients achieved a favorable renal function recovery. Compared with patients who achieved renal function recovery (recovery group), the patients progressed to CKD (progression group) were older and had longer interval from symptom onset to treatment with steroids. The peak serum cystatin C concentration was higher in progression group than recovery group. Higher score of interstitial fibrosis/tubular atrophy (IFTA) and more interstitial inflammatory cells infiltration were detected in renal tissue in progression group. According to multivariable analysis, higher peak cystatin C concentration (OR = 2.443, 95% CI 1.257, 4.746, p = 0.008), longer interval to treatment with corticosteroids (OR = 1.183, 95% CI 1.035, 1.352, p = 0.014) were independent risk factors of progression to CKD. The cutoff value of cystatin C concentration was 4.34 mg/L, at which the sensitivity and specificity were 76.9% and 89.3%, respectively; the cutoff value of interval to treatment with corticosteroids was 22.5 days, at which the sensitivity and specificity were 81.8% and 79.5%, respectively. Conclusion Renal function was reversible in majority of patients with severe DAIN requiring RRT when early identification and treatment. Higher peak cystatin C concentration and longer interval to treatment with corticosteroids associated with worse renal prognosis.

Background Bacterial community-acquired atypical pneumonia is sometimes complicated by a myositis or by a renal parenchymal disease. Available reviews do not mention the concurrent occurrence of both myositis and acute kidney injury. Methods In order to characterize the link between bacterial community-acquired atypical pneumonia and both myositis and a renal parenchymal disease, we reviewed the literature (United States National Library of Medicine and Excerpta Medica databases). Results We identified 42 previously healthy subjects (35 males and 7 females aged from 2 to 76, median 42 years) with a bacterial atypical pneumonia associated both with myositis (muscle pain and creatine kinase ≥5 times the upper limit of normal) and acute kidney injury (increase in creatinine to ≥1.5 times baseline or increase by ≥27 μmol/L above the upper limit of normal). Thirty-six cases were caused by Legionella species (N = 27) and by Mycoplasma pneumoniae (N = 9). Further germs accounted for the remaining 6 cases. The vast majority of cases (N = 36) presented a diffuse myalgia. Only a minority of cases (N = 3) were affected by a calf myositis. The diagnosis of rhabdomyolysis-associated kidney injury was retained in 37 and that of acute interstitial nephritis in the remaining 5 cases. Conclusion Bacterial atypical pneumonia may occasionally induce myositis and secondary kidney damage.

The patient was 74-year-old woman. She underwent open nephrectomy for right kidney cancer with multiple lung metastasis in June X, and was diagnosed as clear cell renal cell carcinoma, pT3bN0M1. Combination therapy with ipilimumab and nivolumab was started in July X. In September X, she presented our hospital with the chief complaint of anorexia. The renal function deteriorated remarkably with serum Cr of 8.58 mg/dL and BUN of 71 mg/dL. CT scan revealed an enlarged left kidney at that time. She was clinically diagnosed as Grade 3 interstitial nephritis caused by immune checkpoint inhibitor, and treatment was initiated immediately. She was treated with steroid therapy and discontinuation of the drugs she was taking, which gradually improved her renal function, and brought it back to baseline in three weeks. After that, the steroid was carefully tapered, and turned off on day 52, and nivolumab monotherapy was resumed on day 60. After five cycles of nivolumab monotherapy, there has been no recurrence of interstitial nephritis, and the disease remains stable. In Japan, 38 cases of interstitial nephritis due to immune checkpoint inhibitors have been reported. In most cases, the diagnosis was made by histological examination; however, we believe that the diagnosis should be made clinically and treatment should be started immediately, since the early treatment is important for immune-related adverse events.

Billions of COVID-19 vaccine doses have been administered to combat the ongoing global pandemic caused by severe acute respiratory syndrome coronavirus-2. While these vaccines are considered safe, with most adverse events being mild to moderate and transient, uncommon systemic side effects of the vaccines, including de novo or re-activation of various glomerular diseases have recently been observed. We report 6 patients who developed glomerular or acute tubulointerstitial disease shortly after receiving COVID-19 vaccinations. Five of these patients received mRNA vaccines (3 Moderna, 2 Pfizer-BioNTech) and 1 received adenovirus-26 vector vaccine (Johnson and Johnson/Janssen). Four of our patients developed de novo glomerulonephritis or acute tubulointerstitial nephritis (ATIN), while the other 2 had re-activation of prior glomerulonephritis. Two patients presented with acute kidney injury (AKI) characterized by severe ATIN. While both of them also had evidence of immune complex glomerular disease, ATIN was the dominant feature on the biopsies. Two other patients presented with high-grade proteinuria and AKI. Like the aforementioned patients, these patients had evidence of immune complex glomerular disease, but acute onset nephrotic syndrome was the leading clinical feature. Another patient presented with de novo myeloperoxidase-anti-neutrophil-cytoplasmic-antibody-associated pauci-immune crescentic glomerulonephritis. Yet another patient had re-activation of immunoglobulin-A glomerulonephritis that had been quiescent for several years prior to the vaccination. It is difficult to ascertain any causal relationship between COVID-19 vaccination and onset/recurrence of kidney diseases. However, vigilance about occurrence of such complications is imperative. Importantly, all our cases responded well to the immunosuppressive treatment.

The debate in this issue of Kidney360 involves the role of kidney biopsy in patients with cancer who develop AKI while receiving immune checkpoint inhibitors (ICPIs). The question is whether we need kidney tissue to diagnose the cause of AKI and guide management in these patients. Two expert onconephrologists, Ben Sprangers and Ilya Glezerman, present the pro and con sides of the debate, respectively. I will provide background on the ICPIs and their associated nephrotoxicity to lay the groundwork for the debate. The ICPIs are humanized mAbs against host immune checkpoints (CTLA-4 and PD-1 receptors and PD ligand-1) that are used to treat a number of different cancers. By attenuating the inhibitory effects of immune checkpoints on T cells, other immune cells, and cancer cells, these agents allow eradication of tumors that would otherwise evade immune destruction (1⇓⇓⇓–5). Although the ICPIs have greatly improved cancer therapy, immune-related adverse drug effects complicate their course (6,7). Extrarenal complications occur relatively commonly; however, drug nephrotoxicity is also observed (7⇓–9). In review articles containing published biopsy-proven cases, acute tubulointerstitial nephritis (ATIN) is most common (51 of 90; 57%), whereas acute tubular injury (ATI; n =13), various glomerulopathies ( n =20), and other kidney lesions ( n =6) have also been described (7⇓⇓–10). In addition, patients with cancer also develop AKI that is unrelated to the ICPI-related toxicity. These include AKI from ischemic and/or nephrotoxic tubular injury, various drug- or cancer-related glomerular injuries, …

BackgroundA renal biopsy is needed to define active inflammatory infiltration and guide therapeutic management in drug-induced acute tubulointerstitial nephritis (D-ATIN). However, factors such as various contraindications, refusal of informed consent and limited technical support may stop the biopsy process. It is thus of great importance to explore approaches that could deduce probable pathologic changes.MethodsA total of 81 biopsy-proven D-ATIN patients were enrolled from a prospective cohort of ATIN patients at Peking University First Hospital. The systemic inflammation score (SIS) was developed based on the CRP and ESR levels at biopsy, and patients were divided into high-SIS, median-SIS, and low-SIS groups. The demographic data, clinicopathologic features, and renal outcomes were compared.ResultsThe SIS was positively correlated with inflammatory cell infiltration and was inversely correlated with interstitial fibrosis. The number of interstitial inflammatory cells increased significantly with increasing SISs. The proportions of neutrophils and plasma cells were the highest in the high-SIS group compared with the other two groups. Prednisone (30–40 mg/day) was prescribed in all patients. The high-SIS group tended to have more favorable renal restoration than the other two groups. By 12 months postbiopsy, a decreased eGFR (2) was observed in 66.7% of medium-SIS patients, 32.4% of high-SIS patients, and 30.4% of low-SIS patients.ConclusionThe SIS was positively correlated with active tubulointerstitial inflammation and therefore could help to aid therapeutic decisions in D-ATIN.

Background Glycosuria is one of the manifestations of acute tubulointerstitial nephritis (ATIN), but may also be observed in other renal diseases. In this study, we investigated the value of non-diabetic glycosuria as a diagnostic clue for ATIN. Methods We retrospectively reviewed the medical records of adult patients who underwent a kidney biopsy as an evaluation for serum creatinine > 1.4 mg/dL. Patients with proteinuria in the nephrotic range, diabetes mellitus, or transplanted kidney were excluded. The laboratory abnormalities suggestive of tubular injury were compared between 28 patients (14 men and 14 women, mean age 48.5 ± 14.1 years) with ATIN and 116 patients (76 men and 40 women, mean age 53.1 ± 15.0 years) with other diagnoses. Results In ATIN, glycosuria (≥ 1+ on dipstick; 68%) was more frequent than hypophosphatemia (18%), hypouricemia (18%), hypokalemia (18%), and tubular proteinuria (40%). In other diagnoses, glycosuria (≥ 1+) was detected in 7 (6%) patients; 6 of them had the histological diagnosis of antineutrophil cytoplasmic antibody-associated glomerulonephritis. The presence of glycosuria (≥ 1+) had 68% sensitivity and 94% specificity for ATIN, with the positive likelihood ratio of 11.24 and the negative likelihood ratio of 0.34. Pyuria and low total CO2 were equally and more sensitive (68% and 71%, respectively) than glycosuria (≥ 1+), but had no diagnostic value due to low specificities (58% and 60%, respectively). Conclusion In non-diabetic, non-nephrotic patients undergoing a kidney biopsy for azotemia, 1+ or higher glycosuria, if present, was a good predictor of the diagnosis of ATIN.

To evaluate the clinical/serological phenotype and outcomes of IgG4-related kidney disease. Case series of IgG4-related kidney disease from a cohort of 69 patients with IgG4-related disease. We defined kidney involvement as the presence of at least one of the following conditions: (A) laboratory parameters of kidney injury (proteinuria and/or elevated creatinine levels and/or hematuria); and/or (B) contrast-enhanced computed tomography features (multiple low-density lesions and/or nephromegaly and/or hypovascular solitary mass and/or renal pelvic lesion and/or perinephric lesions). We identified 17 patients with kidney involvement (24.6%), with a mean age of 53.6 ± 11.3 years; thirteen (76.5%) were male. Six patients fulfilled the laboratory criteria, six the imaging criteria, and five both. Five patients had a renal biopsy, the main histopathological diagnosis being IgG4 tubulointerstitial nephritis. Sixteen patients received glucocorticoids and 12 also immunosuppressors and/or biologics. Sixteen patients presented either total or partial renal remission at a median follow-up of 26 months, while one patient developed end-stage renal disease. Patients with kidney disease, as opposed to patients without kidney involvement, had a higher number of involved organs, higher IgG4-related disease responder index and IgG4 and IgG1 serum levels, higher prevalence of rheumatoid factor, and lower C3 and C4 levels. Our study emphasizes the systemic nature of IgG4-related disease, highlighting that renal involvement is usually present in a subset of patients with multisystemic disease, high IgG1 and IgG4 levels, and hypocomplementemia. Key Points • IgG4-RKD presents at a younger age in Mexican mestizo patients. • IgG4-RKD presents with proteinuria and kidney injury or as an asymptomatic imaging finding. • IgG4-RKD presents in the context of multisystemic disease, hypocomplementemia, and high IgG1 and IgG4 levels.

Hypomagnesemia in patients with congenital anomalies of the kidneys and urinary tract or autosomal dominant tubulointerstitial kidney disease is highly suggestive of HNF1B-associated disease. Intriguingly, the frequency of low serum Mg2+ (sMg) level varies and is lower in children than in adults with HNF1B mutations that could be partially due to application of inaccurate normal limit of sMg, irrespective of age and gender. We aimed to re-assess cross-sectionally and longitudinally the frequency of hypomagnesemia in HNF1B disease by using locally derived reference values of sMg. Fourteen children with HNF1B-associated kidney disease were included. Control group comprising 110 subjects served to generate 2.5th percentiles of sMg as the lower limits of normal. In both controls and patients, sMg correlated with age, gender, and fractional excretion of Mg2+. In girls, sMg concentration was higher than in boys when analyzed in the entire age spectrum (p

Immune checkpoint inhibitors (CPIs), including pembrolizumab, are becoming common oncological treatments. CPIs have been associated with a significant risk of developing immune-related adverse events (irAEs), such as nephritis and interstitial nephritis. However, the occurrence of glomerulonephritis has only rarely been reported. We herein present the case of a 75-year-old woman with non-small cell lung carcinoma (NSCLC) who developed proteinuria and microscopic hematuria during treatment with pembrolizumab. Renal biopsy revealed tubulointerstitial nephritis and IgA nephropathy. Considering that a urinalysis showed no abnormality before treatment, the condition might have been induced by pembrolizumab. In this report, we focus on the correct diagnosis and management of renal irAEs, which remain controversial.

Aims The clinical significance of common histological parameters in acute interstitial nephritis (AIN) is uncertain. We aimed to evaluate the utility of histology in predicting clinical outcomes in patients with AIN. Methods and results Adult renal biopsies yielding a diagnosis of AIN between 2000 and 2015 were re-examined. Patients were divided into groups based on: (i) the percentage of non-fibrotic cortex containing inflammation (NFI score) (NFI-1 = 0-24%; NFI-2 = 25-74%; NFI-3 = 75-100%) and (ii) the percentage of cortex containing tubular atrophy (TA score) (TA1 = 0-9%; TA2 = 10-24%; TA3 = 25-100%). The primary outcome was a composite of ≥50% reduction in serum creatinine (sCr) or an estimated glomerular filtration rate (eGFR) > 60 ml/min/1.73 m2 1 year post-biopsy. From a total of 2817 native renal biopsies, there were 120 patients with AIN and adequate data for analysis. Of these, 66 (56%) achieved the primary outcome. On univariable logistic regression, NFI-3 was associated with a 16 times increased likelihood of achieving the primary outcome compared to NFI-1 [odds ratio (OR) = 16, 95% confidence interval (CI) = 5.2-50)]. In contrast, TA3 was associated with a 90% reduced likelihood of achieving the primary outcome compared to TA1 (OR = 0.10, 95% CI = 0.0-0.3). Maximal clinical utility was achieved by combining TA and NFI into a single prognostic 'TANFI' score, which had an independent predictive effect on the primary outcome in a multivariable regression model consisting of age, sex, baseline sCr and identified drug cause. Conclusions In patients with biopsy-proven AIN, a lower percentage of cortical tubular atrophy and, paradoxically, a higher percentage of inflammation in non-fibrosed cortex were associated with an increased likelihood of a positive clinical outcome.

We herein report a 50-year-old woman who suffered from tubulointerstitial nephritis with antimitochondrial M2 antibody, distal renal tubular acidosis, and Fanconi syndrome. Our case also had interstitial pneumonia. After initially successful glucocorticoid therapy, tubulointerstitial nephritis and interstitial pneumonia relapsed. After the second successful round of glucocorticoid therapy, tubulointerstitial nephritis relapsed again and responded to glucocorticoid and azathioprine. This case might indicate (1) the association between pulmonary involvement and tubulointerstitial nephritis with antimitochondrial antibodies and (2) the need for a maintenance dose of glucocorticoid and immunosuppressants in tubulointerstitial nephritis with antimitochondrial antibodies.

Background Despite increasing recognition of the importance of immune checkpoint inhibitor-associated AKI, data on this complication of immunotherapy are sparse. Methods We conducted a multicenter study of 138 patients with immune checkpoint inhibitor-associated AKI, defined as a ≥2-fold increase in serum creatinine or new dialysis requirement directly attributed to an immune checkpoint inhibitor. We also collected data on 276 control patients who received these drugs but did not develop AKI. Results Lower baseline eGFR, proton pump inhibitor use, and combination immune checkpoint inhibitor therapy were each independently associated with an increased risk of immune checkpoint inhibitor-associated AKI. Median (interquartile range) time from immune checkpoint inhibitor initiation to AKI was 14 (6-37) weeks. Most patients had subnephrotic proteinuria, and approximately half had pyuria. Extrarenal immune-related adverse events occurred in 43% of patients; 69% were concurrently receiving a potential tubulointerstitial nephritis-causing medication. Tubulointerstitial nephritis was the dominant lesion in 93% of the 60 patients biopsied. Most patients (86%) were treated with steroids. Complete, partial, or no kidney recovery occurred in 40%, 45%, and 15% of patients, respectively. Concomitant extrarenal immune-related adverse events were associated with worse renal prognosis, whereas concomitant tubulointerstitial nephritis-causing medications and treatment with steroids were each associated with improved renal prognosis. Failure to achieve kidney recovery after immune checkpoint inhibitor-associated AKI was independently associated with higher mortality. Immune checkpoint inhibitor rechallenge occurred in 22% of patients, of whom 23% developed recurrent associated AKI. Conclusions This multicenter study identifies insights into the risk factors, clinical features, histopathologic findings, and renal and overall outcomes in patients with immune checkpoint inhibitor-associated AKI.

Granulomatous interstitial nephritis (GIN) is a rare cause of renal failure. Most frequent etiologies are sarcoidosis, drugs, granulomatosis with polyangiitis, and infections agents (particularly renal tuberculosis). The aim of this retrospective study was to evaluate the clinical features, causes, and outcomes of patients with GIN in adult patients in a region of Morocco. All native renal biopsy (January 2008 to December 2017) were reviewed, but only cases of GIN were analyzed. Eleven cases of GIN were identified in this study, constituting 2.7 % of all native renal biopsies performed on this period (n = 407). There were 7 (63.6%) women, and the average age was 44.2 ± 13.9 years. The mean serum creatinine level at the renal biopsy was 39.1 ± 20.7 mg/L. The most common etiology was sarcoidosis (45.4%, n = 5) followed by drug-induced GIN (27.2%, n = 3). A good renal outcome was reported in patients with drug-induced GIN and sarcoidosis. However, no renal recovery was described in patients with other etiologies. One information from our report and the previously studies is that better data collection systems such as biopsy registries are needed to provide data on the epidemiology and treatment of rare kidney diseases.

BackgroundAcute tubulointerstitial nephritis (AIN) is an uncommon cause of acute kidney injury in children, accounting for less than 10% of cases. There is limited information regarding the range of underlying diagnoses and how these may differ geographically.We undertook a retrospective case note review of consecutive cases of biopsy-proven AIN, presenting to a single UK tertiary paediatric centre, to describe the range of AIN in our caseload, define key characteristics and response to treatment, with the aim of informing paediatric nephrology practice.MethodsCases were identified retrospectively from departmental records. Data extracted included demographics, presenting clinical and biochemical features, renal biopsy histology, treatment and follow-up.ResultsTen cases were identified over 8 years (2007–2014). Age range 6–16 years. Male:Female ratio 1:9. Final diagnoses included 6 tubulointerstitial nephritis and uveitis syndrome (TINU), 2 idiopathic, 1 sarcoidosis, 1 child with Streptococcal disease. Of the TINU cases, timing of eye symptoms varied in relation to AIN presentation. Cases had a varied investigative work-up.Median presenting plasma creatinine was 303 μmol/l (range 152–932 μmol/l). Renal function improved spontaneously in 1 idiopathic case and improved with antimicrobial treatment in a child with Streptococcal disease.Eight cases received immunosuppressive treatment with intravenous methylprednisolone (approximately 10 mg/kg for 3–5 days) and / or oral prednisolone (1–2 mg/kg initially, reducing over 7–28 days).At 1 month, median creatinine had fallen to 91 μmol/l (range 41–120 μmol/l) with median eGFR 61 ml/min/1.73m2(range 51-103 ml/min/1.73m2). At last follow-up (median 18.5 months, range 2–70 months), median creatinine was 71 μmol/l (range 47–90 μmol/l) with median eGFR 80 ml/min/1.73m2, range 63 to 101 ml/min/1.73m2).Two patients received antihypertensives at diagnosis and 1 further patient at 1 month follow-up. Eight patients received electrolyte supplementation. Median time to discontinuing electrolyte supplementation was 3.5 months (range 1–12 months).ConclusionTo our knowledge, this is the only contemporary UK case series of biopsy-proven AIN in children. Our population has a high proportion of TINU. Treatment was accompanied by improvement of renal function, however 7/10 patients had an eGFR 2at last follow-up. We suggest a standardised investigative work-up and recommend long-term follow-up.

BackgroundBK polyomavirus (BKPyV)-associated nephropathy (BKPyVAN) causes renal allograft dysfunction and graft loss. However, the mechanism of BKPyV replication after kidney transplantation is unclear. Clinical studies have demonstrated that immunosuppressants and renal ischemia–reperfusion injury (IRI) are risk factors for BKPyV infection. Studying the pathogenic mechanism of BKPyV is limited by the inability of BKPyV to infect the animal. Mouse polyomavirus (MPyV) is a close homolog of BKPyV. We used a model of MPyV infection to investigate the core genes and underlying mechanism of IRI and immunosuppressants to promote polyomavirus replication.Materials and MethodsOne-day-old male C57BL/6 mice were intraperitoneally injected with MPyV. At week 9 post-infection, all mice were randomly divided into IRI, immunosuppressant, and control groups and treated accordingly. IRI was established by clamping the left renal pedicle. Subsequently, kidney specimens were collected for detecting MPyV DNA, histopathological observation, and high-throughput RNA sequencing. Weighted gene correlation network analysis (WGCNA), protein–protein interaction network analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to screen for core genes and common signaling pathways involved in promoting MPyV replication by IRI and immunosuppressants.ResultsAfter primary infection, MPyV established persistent infection in kidneys and subsequently was significantly increased by IRI or immunosuppressant treatment individually. In the IRI group, viral loads peaked on day 3 in the left kidney, which were significantly higher than those in the right kidney and the control group. In the immunosuppressant group, viral loads in the left kidney were significantly increased on day 3, which were significantly higher than those in the control group. Protein–protein interaction network analysis and WGCNA screened complement C3, epidermal growth factor receptor (EGFR), and FN1 as core genes. Pathway enrichment analysis based on the IRI- or immunosuppressant-related genes selected by WGCNA indicated that the NF-κB signaling pathway was the main pathway involved in promoting MPyV replication. The core genes were further confirmed using published datasets GSE47199 and GSE75693 in human polyomavirus-associated nephropathy.ConclusionsOur study demonstrated that IRI and immunosuppressants promote polyomavirus replication through common molecular mechanisms. In future studies, knockdown or specific inhibition of C3, EGFR, FN1, and NF-κB signaling pathway will further validate their critical roles in promoting polyomavirus replication.

BACKGROUND: With current immunosuppressive regimens, BK polyomavirus-associated nephropathy (BKPyVAN) is still a matter of concern. Stratification of patients at risk for allograft loss is of uttermost importance to guide treatment choice and assess prognosis. In 2018, the Banff working group proposed a classification scheme for the prognosis of BKPyVAN, but external application on independent cohorts is yet to be performed. We investigated how the 2018 Banff classification would perform in a multicenter cohort comprising 50 cases of biopsy-proven BKPyVAN compared to previously published classification systems. METHODS: We analyzed consecutive BKPyVAN cases from two Dutch university hospitals between 2002 and 2013, retrieved clinical data, and scored all biopsies according to the Banff 2018 classification, and as a comparison, 4 previously proposed BKPyVAN classification systems. We used estimated glomerular filtration rate trajectories and death-censored graft survival as primary endpoints. RESULTS: The 2018 Banff classification did not associate with estimated glomerular filtration rate decline or graft failure and performed only slightly better than the 4 previously proposed classifiers. Anti-human leukocyte antigen donor-specific antibodies (DSAs), especially in combination with ongoing biopsy-proven BKPyVAN on follow-up, did correlate with graft function and survival. Patients who were DSA+/BKPyVAN+ on follow-up had more inflammation at the baseline biopsy, which by itself was not associated with graft outcomes. CONCLUSIONS: Neither the 2018 Banff BKPyVAN classification nor previously published stratification systems could be applied to our multicenter patient cohort. Our data suggest that there might be a prognostic value for follow-up biopsies and DSA measurements to improve risk stratification after BKPyVAN, although prospective multicenter efforts with protocol measurements are needed to confirm this.

Cilostazol is an antiplatelet agent, that has been recently used as an adjunctive therapy in the management of diabetic foot ulcers. Headache, diarrhea, palpitations, and edema are reported as common side effects.A 53-year-old woman was admitted to hospital, with decreased urine output and increased serum creatinine level. She had taken Cilostazol for the first time, for only one day, so the diagnosis of acute kidney injury, probably drug-induced acute interstitial nephritis, due to Cilostazol use, was made. Her kidney function did not improve despite Cilostazol discontinuation and therefore, empirical corticosteroid therapy was initiated. Her urine output increased and her serum creatinine level significantly decreased, on the third day of treatment. She was discharged with acceptable kidney function. Follow-up visits showed gradual normalization of serum creatinine in the next 62 days.Based on our case, we may draw the conclusion that, Cilostazol may cause nephrotoxicity at any point after ingestion. DOI: 10.52547/ijkd.6980.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of autoimmune multisystemic diseases characterized by necrotizing inflammation of small vessels and the presence of circulating ANCA. The prevalence of overlap AAV with other autoimmune diseases was low.We report a case of a 54-year-old woman who presented with a 20-year-history of sicca symptoms, the presence of anti-Ro/SS-A, anti-La/SS-B antibodies, myeloperoxidase -ANCA (MPO-ANCA), significant increase of serum IgG4 level, microscopic hematuria, non-nephrotic proteinuria, and progressive renal dysfunction. A renal biopsy showed pauci-immune necrotizing glomerulonephritis with crescents with severe tubulointerstitial nephritis (TIN) which shows extensive infiltration of IgG4-positive plasma cells. Considering these findings and the clinical course, the disease was considered more likely to be MPO-ANCA-associated vasculitis accompanied by IgG4-TIN with underlying primary Sjögren syndrome (pSS).This report shows a possible unusual disease overlap of MPO-ANCA-associated vasculitis and IgG4-TIN with underlying pSS.

An 81-year-old female was referred to our department 1 year ago due to a worsening renal function. Her manifestations met the criteria of Sjögren syndrome, suggesting renal failure likely resulting from tubulointerstitial nephritis (TIN) due to Sjögren syndrome. However, at her request, she was followed up with no further investigation or treatment. The following July, since her renal function deteriorated again, a renal biopsy was performed. Using IgM-CD138 dual staining, the renal pathology showed the infiltration of accumulated IgM-positive plasma cells within the renal insterstitium, so she was diagnosed with tubulointerstitial nephritis with IgM-positive plasma cells (IgMPC-TIN).IgMPC-TIN, proposed by Takahashi et al. in 2017, as a type of TIN, is characterized by the pathological infiltrations of IgM-positive plasma cells within the renal insterstitium and is effectively treated with corticosteroid therapy. Despite her old age, corticosteroid therapy was performed, resulting in the improvement in her renal function according to blood and urine tests and an improved pulmonary involvement, although renal dysfunction remained.Elderly patients often have multiple underlying medical conditions and take numerous medications, so differentiating renal disorders is challenging. However, a renal biopsy, even in an elderly patient, can aid in identifying the cause of renal disorders and predicting the prognosis. IgMPC-TIN is a condition in which renal function can be expected to improve if treated. It is thus important to make a diagnosis of IgMPC-TIN without overlooking and to consider proper treatment.

Background Acute interstitial nephritis (AIN) is an important cause of kidney injury accounting for up to 27% of unexplained renal impairment. In up to 70% of cases, drugs, including aminosalicylates, are reported as the underlying cause. Following two recent paediatric cases of suspected mesalazine induced AIN within our own department, we performed a systematic review of the literature to address the following question: In patients with inflammatory bowel disease (IBD), is interstitial nephritis associated with 5-aminosalicylate (5-ASA) treatment? Our primary objective was to identify the number of cases reported in the literature of biopsy-proven 5-ASA induced interstitial nephritis, in children and adults with IBD. We also aimed to identify which variables influence the onset, severity and recovery of 5-ASA interstitial nephritis. Methods Embase and PubMed databases were searched from inception to 07/10/20. Search terms had three main themes: “inflammatory bowel disease”, “interstitial nephritis” and “aminosalicylates”. Studies were included if they reported an outcome of AIN, confirmed on biopsy, suspected to be secondary to a 5-ASA drug in those with IBD. A narrative synthesis was performed. Results Forty-one case reports were identified. Mesalazine was the most frequently reported aminosalicylate associated with AIN (95%). The median duration of treatment before AIN was diagnosed was 2.3 years (Interquartile Range (IQR) 12–48 months). The median rise in creatinine was 3.3 times the baseline measurement (IQR 2.5–5.5). Aminosalicylate withdrawal and steroids were the most frequently used treatments. Despite treatment, 15% of patients developed end-stage renal failure. Conclusions AIN is a serious adverse drug reaction associated with aminosalicylates, with mesalazine accounting for most reports. The current guidance of annual monitoring of renal function may not be sufficient to identify cases early. Given the severity of AIN and reports in the literature that early treatment with steroids may be beneficial, we would recommend at least 6 monthly monitoring of renal function. PROSPERO registration number CRD42020205387.

Sjogren's syndrome is a chronic slowly progressive autoimmune disease characterized by lymphocytic infiltration of exocrine glands resulting in xerostomia and dry eyes. The syndrome has wide clinical spectrum from organ specific exocrionopathy to systemic manifestation. The disease can present alone or with other autoimmune diseases like RA, SLE, Scleroderma, autoimmune thyroid disease etc. Prevalence of primary Sjogren's is 0.5-1% and of secondary Sjogren's is 5-20%. Renal involvement is rare and can either be tubulointerstial or glomerular. Based on biopsy reports in the available literature, tubulointerstitial nephritis (TIN) is the most common histological abnormality, followed by glomerulonephritis as a distant second.1 Distal Renal tubular Acidosis is the most common manifestation of TIN. We report a case of a 35 year female with acute onset motor weakness (quadriparesis) with hypokalemia with NAGMA with distal RTA. Patient was diagnosed with Secondary Sjogren's and managed accordingly.

Objectives Acute kidney injury (AKI) is a common diagnosis in hospitalized patients. Dialysis requiring AKI (AKI-D) is associated with adverse outcomes. This study aims to know the clinical profile and short-term outcomes at 3 months, in patients with AKI-D, at our center. Methods A prospective observational study was done of all the patients admitted with AKI-D for 2 years, from July 2018 to June 2020. We recorded clinical parameters at baseline and postdischarge follow-up at 3 months. Results One hundred twenty-eight patients had AKI-D over 2 years. Then, 116 (90.6%) patients had community-acquired AKI (CAAKI), and 12 (9.4%) patients had hospital-acquired AKI. The underlying causes of AKI-D were: toxins in 48 (37.5%), sepsis in 31 (24.2%), acute kidney disease in 15 (11.7%), acute gastroenteritis (AGE) in 9 (7%), and cardiogenic shock in 7 (5.5%) patients. The mean values of intact parathyroid hormone (available in 32% of patients) were 268 pg/mL. Intermittent hemodialysis was the commonest mode of dialysis (85.2%). A kidney biopsy was done in 23 (18%) patients. The most common diagnosis on kidney biopsy was glomerulonephritis (GN) in 12 patients (crescentic GN-9 and IgA nephropathy-3), followed by acute tubule-interstitial nephritis in 6 patients. In-hospital mortality was 29.7%. Overall, 39% regained serum creatinine in the normal range at 3 months, 36.7% died, 14.1% reached chronic kidney disease (CKD), 7.8% lost to follow-up, and 2.3% had reached end-stage renal disease. Conclusion The majority of AKI-D at our center was CAAKI. A significant chunk of AKI-D (68.7%) was caused by preventable causes like toxins, sepsis, and AGE. Dysregulation of mineral metabolism was conspicuous. In chemical toxin vs. biological toxins and undifferentiated sepsis vs. the identifiable cause of sepsis, formers had significantly more in-hospital mortality than the latter ones. AKI-D is associated with high in-hospital mortality, total mortality, and risk of progression to CKD at 3 months.

BACKGROUND AND OBJECTIVES: Immune checkpoint inhibitors are increasingly used to treat various malignancies, but their application in patients with kidney transplants is complicated by high allograft rejection rates. Immune checkpoint inhibitor–associated rejection is a novel, poorly understood entity demonstrating overlapping histopathologic features with immune checkpoint inhibitor–associated acute interstitial nephritis, which poses a challenge for diagnosis and clinical management. We sought to improve the understanding of these entities through biopsy-based gene expression analysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: NanoString was used to measure and compare the expression of 725 immune-related genes in 75 archival kidney biopsies, including a 25-sample discovery cohort comprising pure T cell–mediated rejection and immune checkpoint inhibitor–associated acute interstitial nephritis and an independent 50-sample validation cohort comprising immune checkpoint inhibitor–associated acute interstitial nephritis, immune checkpoint inhibitor–associated T cell–mediated rejection, immune checkpoint inhibitor–associated crescentic GN, drug-induced acute interstitial nephritis, BK virus nephropathy, and normal biopsies. RESULTS: Significant molecular overlap was observed between immune checkpoint inhibitor–associated acute interstitial nephritis and T cell–mediated rejection. Nevertheless, IFI27, an IFN-α–induced transcript, was identified and validated as a novel biomarker for differentiating immune checkpoint inhibitor–associated T cell–mediated rejection from immune checkpoint inhibitor–associated acute interstitial nephritis (validation cohort: P

Autosomal dominant tubulointerstitial kidney disease due to

Rationale: Momordica charantia is often used to treat type 2 diabetes mellitus in Korea. Drug-induced acute interstitial nephritis (AIN) accounts for 60% to 70% of AIN cases. However, only 1 case of AIN associated with ingesting M charantia has been reported in the English literature. We report an extremely rare case of AIN that occurred after a patient ingested a pure M charantia extract over 7 months. Patient concerns: A 60-year-old Korean woman was admitted to our hospital for a renal biopsy. Her renal function had decreased gradually over the last 9 months without symptoms or signs. Diagnosis: Her blood urea nitrogen and serum creatinine levels were 29.7 mg/dL (range: 8.0–20.0 mg/dL) and 1.45 mg/dL (range: 0.51–0.95 mg/dL) on admission. Renal histology indicated AIN; there was immune cell infiltration into the interstitium, tubulitis, and epithelial casts, although the glomeruli were largely intact. Interventions: M charantia was discontinued and prednisolone was prescribed. Outcomes: The value of serum creatinine has almost been restored to the baseline level after 3 months. Conclusion s: This is the first case report of AIN associated with the ingestion of a pure M charantia extract. Recognition of the possible adverse effects of these agents by physicians is very important for early diagnosis and appropriate management.

Interstitial fibrosis and tubular atrophy (IFTA) with inflammation (IFTA-I) is strongly correlated with kidney allograft failure. Diagnosis of IFTA-I accurately and early is critical to prevent graft failure and improve graft survival. In the current study, through analyzing the renal allograft biopsy in patients with stable function after kidney transplantation (STA), IFTA and IFTA-I group with semi-supervised principal components methods, we found that CD2, IL7R, CCL5 based signature could not only distinguish STA and IFTA-I well, but predict IFTA-I with a high degree of accuracy with an area under the curve (AUC) of 0.91 (P = 0.00023). Additionally, IRF8 demonstrated significant differences among STA, IFTA and IFTA-I groups, suggesting that IRF8 had the capacity to discriminate the different classifications of graft biopsies well. Also, with Kaplan-Meier and log-rank methods, we found that IRF8 could serve as the prognostic marker for renal graft failure in those biopsies without rejection (AUC = 0.75) and the recipients expressing high had a higher risk for renal graft loss (P < 0.0001). This research may provide new targets for therapeutic prevention and intervention for post-transplantation IFTA with or with inflammation.

The objective of this study is to investigate the risk factors of renal flare in patients with membranous lupus nephritis (class V lupus nephritis). Biopsy-proven pure membranous lupus nephritis patients diagnosed between January 1997 and September 2017 were studied. We assessed and compared the clinical and pathological parameters between patients who experienced renal flare and those who did not. To identify risk factors of renal flare, multivariable Cox proportional hazard regression analysis was performed. Out of the 53 patients with pure membranous lupus nephritis, 17 patients (32.1%) experienced renal flare during a median follow-up of 121.5 months (range 44.4-196.9). Patients who experienced renal flare had significantly higher proportion of tubulointerstitial inflammation (76.5% vs. 36.1%, p = 0.006) and tubular atrophy/interstitial fibrosis (70.6% vs. 27.8%, p = 0.003) at baseline. In multivariable Cox proportional hazard regression analysis, the presence of tubulointerstitial inflammation [adjusted hazard ratio (HR) 5.532, 95% confidence interval (CI) 1.722-17.776, p = 0.004] and tubular atrophy/interstitial fibrosis (adjusted HR 4.328, 95% CI 1.450-12.916, p = 0.009) at baseline was significantly associated with increased risk of renal flare. The presence of tubulointerstitial inflammation and tubular atrophy/interstitial fibrosis is associated with increased risk of renal flare in patients with membranous lupus nephritis.

A 71-year-old woman with abnormal pulmonary shadows and multiple enlarged thoracic lymph nodes was diagnosed with stage IIB lung adenocarcinoma, pulmonary sarcoidosis, and sarcoidosis-associated lymphadenopathy after biopsies from multiple organ sites. She also had rapidly progressive renal dysfunction, microhematuria, and high myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) concentrations. A renal biopsy revealed granulomatous tubulointerstitial nephritis and necrotizing glomerulonephritis with crescent formation. She was diagnosed with nephritis caused by both sarcoidosis and ANCA-associated vasculitis. Oral prednisolone was administered to treat her nephritis, resulting in improvement in both her renal dysfunction and her sarcoidosis-associated lymphadenopathy.

In sarcoidosis, renal involvement includes hypercalcemia-related nephrocalcinosis and granulomatous tubulointerstitial nephritis. Hypercalcemia is thought to be due to increased production of 1,25 dihydroxyvitamin D (1-25D), but 1-25D levels have not been evaluated in sarcoidosis patients with renal dysfunction. We enrolled 9 sarcoidosis patients who underwent renal biopsy, and compared the serum 1-25D concentration and eGFR with those in 428 non-sarcoidosis patients who had renal dysfunction (stage 2 or higher CKD with an estimated glomerular filtration rate

We present a rare case of Acute Interstitial Nephritis (AIN) that occurred following a re-trial of clozapine in a 56-year-old lady with schizoaffective disorder. On initial trial of clozapine, this patient felt generally unwell with respiratory symptoms. Her inflammatory markers were raised and her renal function showed a mild, transient deterioration which normalised on the day of cessation of clozapine. Two years later, clozapine was re-trialled due the refractory nature of her psychiatric symptoms. She subsequently developed renal failure and AIN was confirmed by renal biopsy. Renal function improved after cessation of clozapine; however, she never fully regained normal renal function.

Context.—Light chain–associated acute tubulointerstitial nephritis (LC-ATIN) is a variant of light chain proximal tubulopathy (LCPT). It is characterized by interstitial inflammation with tubulitis and deposition of monoclonal light chains in the tubulointerstitium. LC-ATIN is a rather poorly recognized pattern of LCPT and not much is known about this entity.Objective.—To determine the clinicopathologic features of patients with LC-ATIN and investigate the proximal tubular injury and mechanism of interstitial inflammation in LC-ATIN.Design.—A total of 38 cases of LC-ATIN were identified from the archives of 5043 renal biopsy specimens. In all cases, routine light microscopic examination, immunofluorescence, and electron microscopic examination were performed. In selected cases, immunofluorescent staining of dendritic cells and immunohistochemical staining for 4 tubular injury markers—KIM-1, p53, bcl-2, and Ki-67—were performed.Results.—A characteristic finding in LC-ATIN cases was immunofluorescence staining of monoclonal light chains along tubular basement membranes in linear fashion and inside proximal tubular cells with a granular pattern. No monoclonal light chains were present in glomerular or vascular compartments confirmed with immunofluorescence, electron microscopy, and ultrastructural gold labeling. Ten of 15 LC-ATIN cases (67%) were concurrently positive for the 4 tubular injury markers. Dendritic cells were identified within the tubulointerstitium in the renal biopsy specimens, interacting with surrounding tubules with light-chain deposits and inflammatory cells.Conclusions.—Significant proximal tubular injury occurs associated with LC-ATIN, and the monoclonal light chains accumulated in proximal tubular cells contribute to the injury. Dendritic cells are involved in the pathogenesis of interstitial inflammation in LC-ATIN.