UNASSIGNED: Acute interstitial nephritis (AIN) is a complication of drugs that may cause permanent kidney injury. AIN has been reported in patients with inflammatory bowel disease (IBD) treated with the integrin inhibitor vedolizumab. Through systematic review of existing literature, we aimed to identify and describe cases of AIN in patients with IBD treated with vedolizumab.
UNASSIGNED: We searched Medline, Embase, Cochrane, and Web of Science Core Collection between 1 January 2009 and 25 April 2023. The search yielded 1473 publications. Titles and abstracts were screened by two independent reviewers. Seventy publications were reviewed in full-text. Eight met the inclusion criteria. Clinical characteristics of AIN cases were extracted. Case causality assessment was performed according to two international adverse drug reaction probability assessment scales. Results were reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
UNASSIGNED: Nine biopsy-confirmed cases of AIN were reported in six patients with ulcerative colitis and three with Crohn\'s disease. Mean age at AIN onset was 36 years (range = 19-58) and the majority of patients were females (n = 6/9). Time from vedolizumab treatment initiation to AIN onset spanned from hours to 12 months. Common symptoms were fever and malaise. Creatinine levels were elevated in all patients. Five patients sustained permanent kidney injury.
UNASSIGNED: Our findings suggest that vedolizumab, although rarely, could cause AIN in patients with IBD. Awareness of laboratory findings and symptoms consistent with AIN, along with monitoring of the kidney function, could be warranted in patients with IBD treated with vedolizumab.

BACKGROUND: Recent studies have focused on immune checkpoint inhibitors. Renal complications associated with the use of immune checkpoint inhibitors are uncommon compared with other immune-related adverse events. Acute interstitial nephritis accounts for most of these renal complications, with nephrotic syndrome quite rare. We herein report a case of nephrotic syndrome associated with immune checkpoint inhibitors that was more severe than that in previous cases. By comparing this case with previous reports, the possible reasons for the particular severity of this case are discussed.
METHODS: A 75-year-old man developed nephrotic syndrome with acute kidney injury after the first combination therapy of nivolumab and ipilimumab for malignant pleural mesothelioma. The results of a kidney biopsy indicated minimal change disease with mild atherosclerosis, acute interstitial nephritis, and fusion of nearly all podocyte foot processes. Nivolumab and ipilimumab therapy were stopped, and treatment with corticosteroids was initiated. We investigated previously reported cases of nephrotic syndrome using immune checkpoint inhibitors. Seventeen cases of immune checkpoint inhibitor-related nephrotic syndrome, including ours, have been reported. Two of the 17 patients with immune checkpoint inhibitor-related nephrotic syndrome required hemodialysis treatment for acute kidney injury. Unlike many previously reported cases, the present patient was administered two different immune checkpoint inhibitors, which may be one of the reasons for the development of severe nephrotic syndrome.
CONCLUSIONS: In addition to previously reported risk factors, immune checkpoint inhibitor combination therapy can exacerbate nephrotic syndrome compared to immune checkpoint inhibitor monotherapy.

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) typically manifests as rapidly progressive glomerulonephritis with crescent formation. In this report, we present a local case of myeloperoxidase (MPO)-AAV-associated acute interstitial nephritis (AIN), showing slight pauci-immune glomerulonephritis and positive MPO-ANCA. This case is characterized by foot process effacement of podocytes in the glomerulus, a favorable prognosis, and an absence of crescentic formation. To further understand this condition, we conducted a comprehensive literature search on Google Scholar and PubMed, employing both free text words and MeSH terms related to \"AAV and AIN.\" This search yielded 24 cases, which we analyzed for their clinical features, laboratory findings, renal pathological characteristics, and therapeutic outcomes. AAV-associated interstitial nephritis predominantly affects elderly patients and is often associated with anemia, proteinuria, hematuria, and nonspecific manifestations, including fever, anorexia, fatigue, edema, and weight loss. Most of the cases in our review were MPO-ANCA-positive and exhibited isolated interstitial inflammation. These patients typically presented with relatively lower levels of serum creatinine, 24-h urine protein levels, and MPO-ANCA titers. All patients in our study received immunosuppressive therapy, including glucocorticoids, immunosuppressants, and rituximab, with the majority achieving clinical remission. Isolated AIN in the context of AAV is a rare occurrence, but it displays distinct clinical, laboratory, and pathological features. Patients with this presentation show a positive response to immunosuppressive treatment. Nevertheless, the establishment of definitive therapy guidelines for AAV-associated AIN remains uncertain and necessitates further investigation to develop comprehensive treatment guidelines. AIN, particularly when lacking typical glomerulus lesions, may represent a novel subgroup within MPO-AAV warranting additional research and clinical attention. Key Points • This study contributes valuable scientific insights by highlighting that MPO-AAV-associated interstitial nephritis, even without crescentic formation, can exhibit podocyte foot process effacement and respond well to treatment. • The presence of AIN, independent of crescentic glomerulonephritis, suggests the potential emergence of a new subclass within MPA-AAV. • Notably, some cases of MPO-AAV-associated AIN may present with normal levels of Scr (Table 5, cases 5, 6, and 17). • This observation highlights the importance of considering renal biopsy, diagnosis, and therapy in a timely manner to prevent the development of chronic kidney disease (CKD).

The 2019 coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) has posed a considerable challenge to global healthcare. Acute interstitial nephritis (AIN) post SARS-CoV-2 infection and vaccination has been reported, but its clinical features and pathogenesis remained unclear. We reviewed so far the largest 22 cases of AIN post SARS-CoV-2 infection and 36 cases of AIN following COVID-19 vaccination. The onset of AIN was mainly related to messenger RNA vaccines (52.8%). Apart from fever, proteinuria (45.5%) was the main manifestation of AIN post SARS-CoV-2 infection, left acute kidney injury (AKI, 63.9%) in patients post COVID-19 vaccination. The potential mechanism of vaccination induced AIN was conjugating vaccines with proteins to form a hapten, which activated dendritic cells and promoted a cascade immunological reaction leading to AIN.

OBJECTIVE: Tubulointerstitial nephritis and uveitis (TINU) syndrome is an uncommon disease. We present a confirmed case of TINU syndrome, and a systematic review of epidemiological characteristics, clinical manifestations, management, and outcomes in Chinese patients.
METHODS: A systematic search was carried out using defined terms and updated up to September 2022, in PubMed, Web of Science, Wanfang, CNKI, and VIP, to identify reported cases of TINU in China, according to PRISMA guidelines.
RESULTS: An 18-year-old boy presented with elevated serum creatinine and 24-h urine protein level of > 2 g. Inspection result revealed acute tubulointerstitial nephritis, and bilateral uveitis. The patient was diagnosed with TINU syndrome and received treatment with methylprednisolone sodium succinate, which resulted in a significant decrease in creatinine and urinary protein levels. Systematic review identified 35 publications that met the inclusion criteria. A total of 71 cases were included in this article, of which 70 were from publications and 1 was from our hospital. The median age at onset was 42 years and was significantly lower in males than females (P < 0.05). The symptoms of uveitis often occurred after kidney injury (54%) and most uveitis was anterior (55%) and bilateral (75%). Among the 51 patients who were followed up for more than 6 months, 24 had recurrent ocular symptoms or progression to chronic uveitis. Twenty patients experienced chronic or progressive kidney disease.
CONCLUSIONS: TINU syndrome is prone to misdiagnosis because kidney damage may not occur simultaneously with uveitis. The incidence of kidney sequelae in children is lower than that in adults, and glucocorticoids are the preferred treatment.
UNASSIGNED: INPLASY202350050.

Renal tubular acidosis is the principal clinical feature associated with tubulointerstitial nephritis in patients with primary Sjögren\'s syndrome. Renal tubular dysfunction due to interstitial nephritis has been considered the underlying pathophysiology connecting renal tubular acidosis and primary Sjögren\'s syndrome. However, the detailed mechanisms underlying the pathophysiology of renal tubular acidosis in primary Sjögren\'s syndrome is not fully understood.
A 30-year-old woman was admitted with complaints of weakness in the extremities. The patient was hospitalized thirteen years earlier for similar issues and was diagnosed with hypokalemic paralysis due to distal renal tubular acidosis with primary Sjögren\'s syndrome. This diagnosis was based on a positive Schirmer\'s test. Besides, anti-Sjögren\'s syndrome-related antigen A was also detected. Laboratory tests indicated distal RTA; however, a renal biopsy showed no obvious interstitial nephritis. Laboratory tests conducted during the second admission indicated distal renal tubular acidosis. Therefore, a renal biopsy was performed again, which revealed interstitial nephritis. Histological analysis of acid-base transporters revealed the absence of vacuolar type H+-ATPases in the collecting duct. The vacuolar type H+-ATPase was also absent in the past renal biopsy, suggesting that the alteration in acid-base transporters is independent of interstitial nephritis.
This case study demonstrates that vacuolar-type H+-ATPases are associated with distal renal tubular acidosis, and distal renal tubular acidosis precedes interstitial nephritis in patients with primary Sjögren\'s syndrome.

Because of their broad-spectrum bactericidal activity, amoxicillin (AMX) and third-generation cephalosporins (TGC) are widely used for the prophylaxis and treatment of established infections. They are considered relatively safe, but several recent reports have suggested substantial nephrotoxicity, especially with AMX use. Considering the importance of AMX and TGC for clinical practice, we conducted this up-to-date review, using the PubMed database, which focuses specifically on the nephrotoxicity of these molecules. We also briefly review the pharmacology of AMX and TGC. Nephrotoxicity of AMX may be driven by several pathophysiological mechanisms, such as a type IV hypersensitivity reaction, anaphylaxis, or intratubular and/or urinary tract drug precipitation. In this review, we focused on the two main renal adverse effects of AMX, namely acute interstitial nephritis and crystal nephropathy. We summarize the current knowledge in terms of incidence, pathogenesis, factors, clinical features, and diagnosis. The purpose of this review is also to underline the probable underestimation of AMX nephrotoxicity and to educate clinicians about the recent increased incidence and severe renal prognosis associated with crystal nephropathy. We also suggest some key elements on the management of these complications to avoid inappropriate use and to limit the risk of nephrotoxicity. While renal injury appears to be rarer with TGC, several patterns of nephrotoxicity have been reported in the literature, such as nephrolithiasis, immune-mediated hemolytic anemia, or acute interstitial nephropathy, which we detail in the second part of this review.

Karyomegalic interstitial nephritis (KIN) is a rare cause of chronic interstitial nephritis characterized by enlarged renal tubular epithelial nuclei. The first case of KIN reported in a kidney graft was in 2019. Here, we report the first case of KIN in 2 brothers receiving kidneys from 2 different unrelated living donors. A male kidney transplant recipient with focal segmental glomerulosclerosis as the original kidney disease presented with graft impairment and proteinuria, and graft biopsy revealed KIN. This patient had a brother who was also a kidney transplant recipient and had one episode of graft impairment and was diagnosed with KIN as well.

BACKGROUND: IgG4-related disease (IgG4-RD) is a newly discovered systemic disease that can affect any organ or tissue in the body. IgG4-related kidney disease (IgG4-RKD) is relatively rare but essential to IgG4-RD. However, there are few reports of IgG4-RD mimicking malignant ureteral tumors leading to hydronephrosis. We report here a rare case of IgG4-RD involving the ureter.
METHODS: An 87-year-old man presented to our nephrology department with anorexia, nausea, and acute kidney injury in November 2020. Urinary computed tomography (CT) examination revealed a right lower ureter mass with right renal and ureter hydronephrosis. The serum level of IgG4 was 1890 mg/dL, and the concurrently renal biopsy revealed extensive infiltration of IgG4-positive plasma cells in renal interstitium, which was diagnosed as IgG4-associated tubule-interstitial nephritis(IgG4-TIN). The renal function improved significantly after double-J tube implantation of the right ureter and moderate-dose hormone therapy. The serum IgG4 decreased to the normal range, and the right lower ureter mass almost disappeared after one year of low-dose hormone maintenance therapy.
CONCLUSIONS: IgG4-RD can present as a mass in the renal pelvis and (or) ureter, leading to hydronephrosis. Therefore, early recognition of this disease is significant. Most patients respond well to hormonal therapy to avoid surgical treatment due to misdiagnosis as malignant tumors, causing secondary harm to patients.

Sarcoidosis is a non-necrotizing granulomatous inflammatory multisystemic disorder of unknown etiology. In children, as in adults, it can involve a few or all organ systems to a varying extent and degree, entailing multisystemic manifestations. Kidney involvement in pediatric-onset adult-type sarcoidosis is rare, with a wide range of renal manifestations, most of them related to calcium metabolism. Children with renal sarcoidosis tend to be more symptomatic than adults, although male patients have a higher prevalence. We present the case of a 10-year-old boy who presented with advanced renal failure with nephrocalcinosis and important hepatosplenomegaly. The diagnosis was established by histopathological examination, with consequent cortisone therapy and hemodialysis. This review emphasizes that sarcoidosis should be considered in the differential diagnosis of pediatric patients with acute kidney insufficiency or chronic kidney disease of an unknown etiology. As far as we know, this is the first study regarding extrapulmonary sarcoidosis in children from Romania.