Global burden of anticancer drug-induced acute kidney injury and tubulointerstitial nephritis from 1967 to 2023.

This study aims to figure out the worldwide prevalence of anticancer therapy-associated acute kidney injury (AKI) and tubulointerstitial nephritis (TIN) and the relative risk of each cancer drug. We conducted an analysis of VigiBase, the World Health Organization pharmacovigilance database, 1967-2023 via disproportionate Bayesian reporting method. We further categorized the anticancer drugs into four groups: cytotoxic therapy, hormone therapy, immunotherapy, and targeted therapy. Reporting odds ratio (ROR) and information component (IC) compares observed and expected values to investigate the associations of each category of anticancer drugs with AKI and TIN. We identified 32,722 and 2056 reports (male, n = 17,829 and 1,293) of anticancer therapy-associated AKI and TIN, respectively, among 4,592,036 reports of all-drug caused AKI and TIN. There has been a significant increase in reports since 2010, primarily due to increased reports of targeted therapy and immunotherapy. Immunotherapy exhibited a significant association with both AKI (ROR: 8.92; IC0.25: 3.06) and TIN (21.74; 4.24), followed by cytotoxic therapy (7.14; 2.68), targeted therapy (5.83; 2.40), and hormone therapy (2.59; 1.24) for AKI, and by cytotoxic therapy (2.60; 1.21) and targeted therapy (1.54; 0.61) for TIN. AKI and TIN were more prevalent among individuals under 45 years of age, with a female preponderance for AKI and males for TIN. These events were reported in close temporal relationship after initiation of the respective drug (16.53 days for AKI and 27.97 days for TIN), and exhibited a high fatality rate, with 23.6% for AKI and 16.3% for TIN. These findings underscore that kidney-related adverse drug reactions are of prognostic significance and strategies to mitigate such side effects are required to optimize anticancer therapy.

Glucocorticoid does not improve the renal prognosis of patients with diabetic nephropathy combined with acute tubulointerstitial nephritis: a retrospective analysis.

BACKGROUND AND OBJECTIVES: In clinical practice, some patients are diagnosed with diabetic nephropathy (DN) combined with acute tubulointerstitial nephritis (ATIN) through renal biopsy. There is relatively little research on the treatment and prognosis of such patients, and no consensus exists on the use of glucocorticoid for treatment. Therefore, our study explores the progression of DN combined with ATIN and the renal outcomes after treatment with glucocorticoid. METHODS: This study retrospectively analyzed patients diagnosed with DN combined with ATIN through renal biopsy at our center from January 1, 2015, to December 31, 2021. We collected general patient information, laboratory indicators, renal pathology indicators, and the glucocorticoid usage after kidney biopsy. Follow-up data were collected from medical records. Statistical analysis methods included t-tests, non-parametric tests, and chi-square tests. Univariate and multivariate Cox regression analyses were used to evaluate the risk factors for renal endpoint events in patients. Statistical significance was defined as p-values < 0.05. RESULTS: In this study, a total of 67 patients were included. The subjects were divided into two groups based on whether they received glucocorticoid treatment: 33 patients in the steroid group and 34 in the non-steroid group. In the steroid group, 19 patients reached the renal endpoint event, which was significantly higher than in the non-steroid group (57.58% vs. 29.41%, p = 0.038). Univariate Cox regression analysis showed that serum creatinine (HR = 1.008, p < 0.001), albumin (HR = 0.919, p < 0.001), 24-h urinary protein (HR = 1.093, p = 0.002), hemoglobin (HR = 0.964, p = 0.001), triglycerides (HR = 1.12, p = 0.04), and the use of glucocorticoid (HR = 2.507, p = 0.019) were influencing factors for renal endpoint events in patients with DN combined with ATIN. Multivariate Cox regression analysis showed that albumin (HR = 0.863, p = 0.003) was an independent risk factor for renal endpoint events in patients with DN combined with ATIN. CONCLUSIONS: The use of glucocorticoid in treatment does not improve renal prognosis in patients with DN combined with ATIN. Lower levels of albumin are associated with a worse renal prognosis.

Successful treatment of acute tubulointerstitial nephritis probably due to Benikoji CholesteHelp®, a supplement containing red yeast rice.

Red yeast rice has been used to produce alcoholic beverages and various fermented foods especially in East Asia. Since around March 2024, there have been many cases of kidney dysfunction in people who have taken certain supplements containing red yeast rice in Japan. We experienced a case of acute kidney injuries induced after taking a supplement containing red yeast rice. A 58-year-old woman was admitted to our hospital due to renal dysfunction suspected to be caused by taking the supplement Benikoji CholesteHelp®, which contains red yeast rice. With elevations of urinary tubular injury markers such as urinary ß2-microglobulin and N-acetyl-ß-D-glucosaminidase, serum creatinine levels were elevated up to 2.75 mg/dL. A kidney biopsy revealed a diagnosis of tubulointerstitial nephritis with lymphocytic infiltration of the interstitium, tubular atrophy, and interstitial fibrotic changes. After discontinuation of the supplement and initiation of the prednisolone treatment, renal dysfunction rapidly improved. The course of this case suggests tubular damage caused by the supplements containing red yeast rice. For early diagnosis and treatment, it should be noted that even what are regarded as nutritional health supplements can cause renal dysfunction.

Granulomatous Tubulointerstitial Nephritis in a Kidney Allograft: Treatment with Interleukin-6 Receptor Antagonist Stabilises Kidney Function.

Granulomatous tubulointerstitial nephritis (GTIN) attributed to early onset sarcoidosis is an ultrarare finding in an allograft kidney biopsy. We present the case of a young man with allograft dysfunction who had GTIN upon biopsy. We performed a thorough case review based on recovered records from early childhood and reassessed genetic testing results. We revised his underlying diagnosis from cryopyrin-associated periodic syndrome to early-onset sarcoidosis with wild-type NOD2 and established a rationale to use the interleukin-6 (IL-6) receptor blocker tocilizumab (TCZ). This suppressed his inflammatory disease and stabilised kidney function. We performed a literature review related to the emerging role of IL-6 pathway blockade in kidney transplantation. We identified 18 reports with 417 unique patients treated with TCZ for indications including HLA-desensitisation, transplant immunosuppression induction, treatment of chronic antibody-mediated rejection, and treatment of subclinical rejection. Both TCZ and the direct IL-6 inhibitor clazakizumab are being studied in ongoing randomised control trials.

Deciphering three predominant biopsy-proven phenotypes of IgG4-associated kidney disease: a retrospective study.

Background: IgG4-associated kidney disease (IgG4-RKD) encompasses a spectrum of disorders, predominantly featuring tubulointerstitial nephritis (TIN) and membranous glomerulonephropathy (MGN). The limited understanding of the co-occurrence of IgG4-RD-TIN with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) poses a diagnostic and therapeutic challenge. Methods: We examined 49 cases, comprising 21 cases of IgG4-RD-TIN (group A), 10 cases of IgG4-RD-TIN accompanied with MGN (group B), and 18 cases of IgG4-RD-TIN concurrent with AAV (group C), at the First Affiliated Hospital of Zhejiang University, China, from June 2015 to December 2022. Results: The mean age and gender of the three IgG4-RKD subtypes were not statistically significant. IgG4-RD-TIN exhibited higher serum creatinine and a higher incidence of hypocomplementemia (group A 47.6%, group B 30%, group C 16.7%). IgG4-RD-TIN-MGN was characterized by proteinuria (group A 0.3 g/d, group B 4.0 g/d, group C 0.8 g/d, P < 0.001) and hypoalbuminemia. IgG4-RD-TIN-AAV exhibited hypohemoglobinemia (group A 103.45 g/l, group B 119.60 g/l, group C 87.94 g/l, P < 0.001) and a high level of urine erythrocytes. The primary treatment for IgG4-RD-TIN was steroids alone, whereas IgG4-RD-TIN-MGN and IgG4-RD-TIN-AAV necessitated combination therapy. Group A experienced two relapses, whereas groups B and C had no relapses. There was no significant difference in patient survival among the three groups, and only two cases in group C suffered sudden death. Conclusions: This study provides valuable insights into clinical manifestations, auxiliary examination features, pathological characteristics, and prognosis of IgG4-RD-TIN, IgG4-RD-TIN-MGN, and IgG4-RD-TIN concurrent AAV. Large-scale studies are required to validate these findings.

Acquired Fanconi syndrome in mixed cryoglobulinemia patients: a single-center case series.

PURPOSE: Cryoglobulinemia is a pathological condition characterized by the presence of cryoglobulins in the blood, with cryoglobulinemic glomerulonephritis being the most frequent form of renal involvement. Fanconi syndrome presents as a generalized dysfunction of the proximal tubule, characterized by the presence of polyuria, phosphaturia, glycosuria, proteinuria, proximal renal tubular acidosis, and osteomalacia. We aimed to present five cases co-occurring with Fanconi syndrome and cryoglobulinemia. METHODS: We retrospectively summarized the cases of five patients with Fanconi syndrome and cryoglobulinemia at Peking Union Medical College Hospital from January 2012 to June 2022. The clinical features, diagnosis, treatment, and prognosis were systematically analyzed. RESULTS: All five patients exhibited typical features of Fanconi syndrome, and cryoglobulinemia was concurrently detected in all cases. These patients also exhibit positive anti-nuclear antibody spectrum and hyperglobulinemia, and IgM constitutes the predominant monoclonal component in cryoglobulins. In addition to supplemental treatment, timely immunosuppressive therapy may potentially benefit the long-term renal prognosis of patients with this condition. CONCLUSION: Our findings highlight the rare co-occurrence of Fanconi syndrome and cryoglobulinemia in clinical practice. Despite the lack of causal evidence, the coexistence of Fanconi syndrome and tubulointerstitial injury is also noteworthy in patients with cryoglobulinemia, underscoring the importance of thorough evaluation and tailored management in patients presenting with overlapping renal manifestations. Key Points • Patients with mixed cryoglobulinemia can clinically present with tubulointerstitial injury, specifically manifesting as Fanconi syndrome. • In addition to typical symptoms of Fanconi syndrome, these patients also exhibit positive anti-nuclear antibody spectrum and hyperglobulinemia, while IgM constitutes the monoclonal component in cryoglobulins. • Timely immunosuppressive therapy may improve long-term renal prognosis in these patients.

Tubulointerstitial nephritis with IgG4-positive plasma cell infiltration and tertiary lymphoid tissue in a patient with cryoglobulinemic vasculitis: a case report.

Tertiary lymphoid tissue (TLT) develops at sites of chronic immune stimulation, including infection, autoimmune disease, transplant rejection, and cancer. Recently, TLT has been focused on an indicator for poor renal prognosis in various kidney diseases. In cryoglobulinemic vasculitis (CV), specific glomerular and vascular lesions are seen; however, tubulointerstitial lesions are usually nonspecific. We herein report the case of a 74-year-old man with idiopathic CV with rare tubulointerstitial lesions, such as tubulointerstitial nephritis (TIN) with IgG4-positive plasma cell infiltration and TLT. To our knowledge, this is the first report identifying TLT in the kidney biopsy in a patient with CV. Glucocorticoid improved the renal outcome. The association between CV and TIN with TLT remains unknown.

A case of immunoglobulin G4-related kidney disease manifesting after dipeptidyl peptidase-4 inhibitor treatment.

A 68-year-old man with type 2 diabetes mellitus was admitted with decreased renal function. He had high IgG4 (1070 mg/dL) and hypocomplementemia (CH50, 25 U/mL). Kidney biopsy showed tubulointerstitial nephritis with IgG4-positive plasma cell infiltration. Four years later, a second kidney biopsy revealed a new manifestation of membranous nephropathy and tubulointerstitial nephritis with exacerbated fibrosis formation. Six years later, the patient developed bullous pemphigoid, which was thought to be caused by DPP4 inhibitors, so DPP4 inhibitor treatment was discontinued. The use of DPP4 inhibitors correlated with changes in renal function, and the patient was diagnosed with IgG4-related kidney disease related to DPP4 inhibitors.

Tubulointerstitial Nephritis and Uveitis: A Case Report.

Tubulointerstitial nephritis and uveitis (TINU) is a rare disease of unknown pathogenesis that is characterized by tubulointerstitial nephritis and uveitis. Currently, there are over 250 reported cases of TINU syndrome. TINU syndrome typically presents with mild uveitis and nephritis that is self-limited; however, in this case, the symptoms were severe making it different from previous case reports. We present a case of a 29-year-old female with a history of cytomegalovirus (CMV) with a recent diagnosis of bilateral uveitis who was admitted for worsening systemic symptoms. Laboratory testing revealed acute renal insufficiency along with hematuria and proteinuria. A kidney biopsy revealed tubulointerstitial nephritis, and the patient was initiated on corticosteroids for the diagnosis of TINU. The patient's renal function recovered to baseline after a prolonged three-month course of systemic steroids but had a recurrence of her uveitis with steroid taper requiring initiation of steroid-sparing therapies. TINU syndrome should be considered in patients presenting with uveitis and renal dysfunction. Prompt diagnosis is necessary to preserve renal function with corticosteroids. The prognosis for patients with TINU is variable, with a frequently recurring and relapsing course. More research is needed to determine the optimal treatment.

Predominant CD8+ cell infiltration and low accumulation of regulatory T cells in immune checkpoint inhibitor-induced tubulointerstitial nephritis.

Immune checkpoint inhibitors (ICIs) can provide survival benefits to cancer patients; however, they sometimes result in the development of renal immune-related adverse events (irAEs). Tubulointerstitial nephritis (TIN) is the most representative pathological feature of renal irAEs. However, the clinicopathological entity and underlying pathogenesis of ICI-induced TIN are unclear. Therefore, we compared the clinical and histological features of this condition with those of non-ICI drug-induced TIN. Age and C-reactive protein levels were significantly higher in ICI-induced TIN, but there were no significant differences in renal function. Immunophenotyping of ICI-induced TIN showed massive T cell and macrophage infiltration with fewer B cells, plasma cells, neutrophils, and eosinophils. Compared with those in non-ICI drug-induced TIN, CD4+ cell numbers were significantly lower in ICI-induced TIN but CD8+ cell numbers were not significantly different. However, CD8/CD3 and CD8/CD4 ratios were higher in ICI-induced TIN. Moreover, CD25+ and FOXP3+ cells, namely regulatory T cells, were less abundant in ICI-induced TIN. In conclusion, T cell, B cell, plasma cell, neutrophil, and eosinophil numbers proved useful for differentiating ICI-induced and non-ICI drug-induced TIN. Furthermore, the predominant distribution of CD8+ cells and low accumulation of regulatory T cells might be associated with ICI-induced TIN development.

Immunoglobulin G4-related disease presenting with nephrotic syndrome due to minimal change disease: a case report.

BACKGROUND: Immunoglobulin G4-related disease is an inflammatory disease affecting multiple organs including the kidney. Immunoglobulin G4-related kidney disease most commonly manifests as a tubulointerstitial nephritis and is associated with glomerular disease in a proportion of cases. Membranous nephropathy is the most frequent glomerular lesion. Herein, we report the first documented case of immunoglobulin G4-related disease presenting with nephrotic syndrome owing to minimal change disease. CASE PRESENTATION: A 67-year-old South Asian male presented to our service with systemic upset and leg swelling. He had heavy proteinuria (urine protein:creatinine ratio 1042 mg/mmol) and was hypoalbuminemic (17 g/L) and hypercholersterolemic (9.3 mmol/L), consistent with the nephrotic syndrome. His serum creatinine was 140 µmol/L, and he was hypocomplementemic (C3 0.59 g/L, C4 < 0.02 g/L) with raised immunoglobulin G4 subclass levels (5.29 g/L). Kidney biopsy demonstrated minimal change disease alongside a plasma-cell-rich tubulointerstitial nephritis with strong positive staining for immunoglobulin G4. A diagnosis of minimal change disease in the setting of immunoglobulin G4-related disease was made. He was commenced on oral prednisolone at 60 mg daily but suffered infectious complications, including necrotizing fasciitis within 3 weeks of starting treatment, ultimately resulting in his death 52 days after initial presentation. CONCLUSION: This case highlights the potential for immunoglobulin G4-related disease to be associated with a spectrum of glomerular pathologies including minimal change disease. It adds to the differential diagnosis of secondary causes of minimal change disease, and moreover, aids as an important reminder of the potential complications of high-dose steroids used in its treatment.

Monocytes and Macrophages in Kidney Disease and Homeostasis.

The monocyte-macrophage lineage of inflammatory cells is characterized by significant morphologic and functional plasticity. Macrophages have broad M1 and M2 phenotype subgroups with distinctive functions and dual reno-toxic and reno-protective effects. Macrophages are a major contributor to injury in immune-complex-mediated, as well as pauci-immune, glomerulonephritis. Macrophages are also implicated in tubulointerstitial and vascular disease, though there have not been many human studies. Patrolling monocytes in the intravascular compartment have been reported in auto-immune injury in the renal parenchyma, manifesting as acute kidney injury. Insights into the pathogenetic roles of macrophages in renal disease suggest potentially novel therapeutic and prognostic biomarkers and targeted therapy. This review provides a concise overview of the macrophage-induced pathogenetic mechanism as a background for the latest findings about macrophages' roles in different renal compartments and common renal diseases.

Two acute kidney injury episodes after ICI therapy: a case report.

A 74-year-old Japanese male with lung squamous cell carcinoma received his first dose of immune checkpoint inhibitors (ICIs): ipilimumab and nivolumab. He developed acute kidney injury (AKI) and was admitted to our department. We diagnosed kidney immune-related adverse effects (irAE), and a kidney biopsy revealed acute tubulointerstitial nephritis. We started oral prednisolone (PSL) and his AKI immediately improved. The patient maintained stable findings after PSL was tapered off. However, seven months after the ICI administration, he developed rapid progressive glomerular nephritis and was admitted to our department again. The second kidney biopsy showed findings consistent with anti-glomerular basement membrane glomerulonephritis. Although the patient was treated with pulse methylprednisolone followed by oral PSL and plasma exchange, he became dependent on maintenance hemodialysis. To our knowledge, no case report has described two different types of biopsy-proven nephritis. In cases of suspected relapsing kidney irAEs, both a relapse of previous nephritis and the development of another type of nephritis should be considered.

Identification of tyrosine brominated extracellular matrix proteins in normal and fibrotic lung tissues.

Peroxidasin (PXDN) is a secreted heme peroxidase that catalyzes the oxidative crosslinking of collagen IV within the extracellular matrix (ECM) via intermediate hypobromous acid (HOBr) synthesis from hydrogen peroxide and bromide, but recent findings have also suggested alternative ECM protein modifications by PXDN, including incorporation of bromide into tyrosine residues. In this work, we sought to identify the major target proteins for tyrosine bromination by HOBr or by PXDN-mediated oxidation in ECM from mouse teratocarcinoma PFHR9 cells. We detected 61 bromotyrosine (BrY)-containing peptides representing 23 proteins in HOBr-modified ECM from PFHR9 cells, among which laminins displayed the most prominent bromotyrosine incorporation. Moreover, we also found that laminin α1, laminin ß1, and tubulointerstitial nephritis antigen-like (TINAGL1) contained BrY in untreated PFHR9 cells, which depended on PXDN. We extended these analyses to lung tissues from both healthy mice and mice with experimental lung fibrosis, and in lung tissues obtained from human subjects. Analysis of ECM-enriched mouse lung tissue extracts showed that 83 ECM proteins were elevated in bleomycin-induced fibrosis, which included various collagens and laminins, and PXDN. Similarly, mRNA and protein expression of PXDN and laminin α/ß1 were enhanced in fibrotic mouse lung tissues, and also in mouse bone-marrow-derived macrophages or human fibroblasts stimulated with transforming growth factor ß1, a profibrotic growth factor. We identified 11 BrY-containing ECM proteins, including collagen IV α2, collagen VI α1, TINAGL1, and various laminins, in both healthy and mouse fibrotic lung tissues, although the relative extent of tyrosine bromination of laminins was not significantly increased during fibrosis. Finally, we also identified 7 BrY-containing ECM proteins in human lung tissues, again including collagen IV α2, collagen VI α1, and TINAGL1. Altogether, this work demonstrates the presence of several bromotyrosine-modified ECM proteins, likely involving PXDN, even in normal lung tissues, suggesting a potential biological function for these modifications.

Tubulointerstitial nephritis antigen-like 1 from cancer-associated fibroblasts contribute to the progression of diffuse-type gastric cancers through the interaction with integrin ß1.

BACKGROUND: Tumor cells of diffuse-type gastric cancer (DGC) are discohesive and infiltrate into the stroma as single cells or small subgroups, so the stroma significantly impacts DGC progression. Cancer-associated fibroblasts (CAFs) are major components of the tumor stroma. Here, we identified CAF-specific secreted molecules and investigated the mechanism underlying CAF-induced DGC progression. METHODS: We conducted transcriptome analysis for paired normal fibroblast (NF)-CAF isolated from DGC patient tissues and proteomics for conditioned media (CM) of fibroblasts. The effects of fibroblasts on cancer cells were examined by transwell migration and soft agar assays, western blotting, and in vivo. We confirmed the effect of blocking tubulointerstitial nephritis antigen-like 1 (TINAGL1) in CAFs using siRNA or shRNA. We evaluated the expression of TINAGL1 protein in frozen tissues of DGC and paired normal stomach and mRNA in formalin-fixed, paraffin-embedded (FFPE) tissue using RNA in-situ hybridization (RNA-ISH). RESULTS: CAFs more highly expressed TINAGL1 than NFs. The co-culture of CAFs increased migration and tumorigenesis of DGC. Moreover, CAFs enhanced the phosphorylation of focal adhesion kinase (FAK) and mesenchymal marker expression in DGC cells. In an animal study, DGC tumors co-injected with CAFs showed aggressive phenotypes, including lymph node metastasis. However, increased phosphorylation of FAK and migration were reduced by blocking TINAGL1 in CAFs. In the tissues of DGC patients, TINAGL1 was higher in cancer than paired normal tissues and detected with collagen type I alpha 1 chain (COL1A1) in the same spot. Furthermore, high TINAGL1 expression was significantly correlated with poor prognosis in several public databases and our patient cohort diagnosed with DGC. CONCLUSIONS: These results indicate that TINAGL1 secreted by CAFs induces phosphorylation of FAK in DGC cells and promotes tumor progression. Thus, targeting TINAGL1 in CAFs can be a novel therapeutic strategy for DGC.

A Case of Combination of IgA Nephropathy and Interstitial Nephritis After COVID-19 Vaccination.

A 66-year-old male presented with renal dysfunction. At the time of presentation, his serum creatinine (sCr) was 2.55 mg/dL, estimated glomerular filtration rate (eGFR) was 20.93 ml/min/1.73 m2, urinary red blood cell (RBC) was 30-49/high power field, and urine protein-creatinine ratio was 0.43 g/gCr. The patient had no urinalysis abnormalities or renal dysfunction within the year prior to presentation but had gross hematuria after the third and fourth coronavirus disease 2019 (COVID-19) vaccinations. Therefore, immunoglobulin A nephropathy (IgAN) was suspected and a percutaneous renal biopsy was performed. Renal pathology confirmed IgAN and interstitial nephritis and glucocorticoid therapy was initiated. Glucocorticoids improved renal function, and microscopic hematuria resolved. Although previous reports have shown that the COVID-19 vaccine induces various renal diseases, complications associated with these two renal diseases are rare. In this case, while IgAN was suspected based on episodes of gross hematuria after vaccination, renal biopsy confirmed it and also revealed interstitial nephritis.

Coexistence of Diffuse Large B-Cell Lymphoma With Chronic Tubulointerstitial Nephritis: A Case Review and Pathophysiology.

There is an association between lymphomas and kidney disease with renal abnormalities found both in patients with direct infiltration by lymphoma as well as in patients without gross or microscopic evidence of renal involvement. Multiple mechanisms to explain the link between lymphomas and renal disease have been proposed, ranging from direct renal metastasis by the lymphoma to chemokine signaling pathways. In addition, there is a correlation between certain genetic mutations and an increased risk of lymphoma metastasizing to other organs. We present a case of a 41-year-old male who passed away due to end-stage kidney disease and was found on autopsy to have chronic tubulointerstitial nephritis and diffuse large B-cell lymphoma (DLBCL) without direct renal involvement by the lymphoma. The patient had been previously healthy with no significant prior medical history, NSAID, or other contributory medication use of note with the only presenting symptom being renal failure. Only upon autopsy was DLBCL discovered throughout the abdomen with no direct lymphoma involvement evident in the kidneys. To the author's knowledge, this is one of the few reported cases of DLBCL in English literature without renal infiltration in which the presenting symptom and cause of death was renal dysfunction. Several mechanisms have been theorized for how lymphomas can lead to kidney damage without direct metastasizes; however, more research still needs to be done to better understand the underlying etiology. Given the rarity and the lack of direct infiltration of lymphoma into the kidneys in this patient, we hope reporting this case will allow further advancements in this field of study as well as more comprehensive management.

Acute Tubulointerstitial Nephritis due to Human Papillomavirus Vaccination.

Acute tubulointerstitial nephritis (ATIN), a rare cause of acute kidney injury in children, is caused by various factors such as drugs, infection, and systemic inflammation. We herein present a case of ATIN with mild encephalitis/encephalopathy with reversible splenial lesion (MERS)-like findings on head magnetic resonance imaging (MRI), which was associated with human papillomavirus (HPV) vaccination. A 14-year-old girl presented to our hospital with a high fever for 5 days. Results of common laboratory tests were normal except for increased C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR). Antibiotics were administered, and the fever promptly resolved after admission. After 7 weeks, she was readmitted due to a high fever for 4 days. In addition to increased CRP levels and ESR, urine test revealed high urine N-acetyl-ß-D-glucosaminidase and ß-2-microglobulin levels, and a renal scintigram showed mild bilateral uptake of 67Ga-citrate, consistent with the pathology of ATIN. Furthermore, head MRI, which was performed because the patient experienced prolonged headaches, revealed MERS-like lesions, although she did not have other neurological symptoms. Detailed examination of her medical records revealed that she had developed high fever 10 days after the third HPV vaccination and another previous episode of high fever 12 weeks after the second HPV vaccination. Based on these findings, we concluded that the ATIN and MERS-like lesions could have been associated with HPV vaccination. Although HPV vaccination is important for preventing uterine cancer, physicians must be vigilant about its various potential adverse effects, including ATIN.

IgG4-related kidney disease: Clinicopathologic features, differential diagnosis, and mimics.

IgG4-related kidney disease (IgG4-RKD) encompasses all forms of kidney disease that are part of IgG4-related disease (IgG4-RD). First recognized as IgG4-related tubulointerstitial nephritis (IgG4-TIN), and then IgG4-related membranous glomerulonephritis (IgG4-MGN), we now recognize additional patterns of interstitial nephritis, glomerular disease, and vascular disease that can be seen as part of IgG4-RKD. The clinical presentation is variable and can include acute or chronic kidney injury, proteinuria or nephrotic syndrome, mass lesion(s), and obstruction. While usually associated with other organ involvement by IgG4-RD, kidney-alone involvement is present in approximately 20 % of IgG4-RKD. Compared to IgG4-RD overall, patients with IgG4-RKD are more likely to show increased serum IgG4 or IgG, and more likely to have hypocomplementemia. In this review, we extensively cover other types of autoimmune and plasma cell-rich interstitial nephritis, mass forming inflammatory diseases of the kidney, and other mimics of IgG4-TIN, in particular ANCA-associated disease.

Tubulointerstitial Nephritis and Uveitis Syndrome: A Report of 6 Cases with Renal Biopsy and Electron Microscopy Evaluation.

Tubulointerstitial nephritis with uveitis syndrome is a rare, immune-mediated entity, characterized by oculo-renal inflammation. Diagnosis requires the exclusion of all other causes of tubulointerstitial nephritis (TIN). We present 6 patients with clinical, laboratory, and renal biopsy findings denotative of tubulointerstitial nephritis with uveitis syndrome. All our patients experienced ocular and renal manifestations, defined by bilateral uveitis and photosensitivity, along with a decline of renal function. In some patients, increased serum creatinine was accompanied by non-nephrotic range proteinuria, glucosuria or "full-blown" Fanconi syndrome. The rest of the laboratory evaluation was normal apart from the presence of elevated erythrocyte sedimentation rate and increased urine ß2-microglobulin, as well as normochromic, normocytic anemia in some cases. All patients underwent renal biopsy. Histochemical (PAS, Masson, silver, Congo-red) and immunohistochemical stains for immune cell populations (CD3, CD20, CD4, CD8, PGM1, CD138) and for the assessment of ß2-microglobulin were conducted. Electron microscopy examination of the biopsies was also performed. Follow-up, ranging from 18 months to 10 years, was available for 4 patients. Histological evaluation revealed interstitial inflammatory infiltration consisting mainly of lymphocytes, with a T-cell predominance, along with several macrophages. Inflammation severity varied among different patients, with some showing scarce foci of immune cell clusters, while others demonstrated a dense, diffuse interstitial infiltration. Interestingly, in 2 cases, a granulomatous pattern, characterized by non-necrotic, ill-defined granulomas was detected. Tubulitis was also encountered in some patients. A divergence was noted regarding the chronicity index, with different levels of tubular atrophy, interstitial fibrosis, and global glomerulosclerosis among different cases. ß2-Microglobulin immunohistochemical evaluation revealed a substantial diminishment of cytoplasmic staining in tubular epithelial cells compared to control kidneys. The most notable finding derived from electron microscopy examination was the presence, in 1 patient, of scattered granular electron-dense deposits along some tubular basement membranes. First-line treatment included steroids, supplemented in some cases by additional immunosuppressive agents. Three patients experienced a partial or complete response, while progressive renal damage was observed in a case with severe chronic lesions and persistence of inflammation-triggering factor. Our cases seem to represent progressive stages within the continuum of disease evolution. Patients with more prominent inflammation might represent a more initial state, while those with a more severe chronicity index, probably depict more advanced stages. While the predominance of T-cells predicates a cell-mediated autoimmune mechanism, as the driving force of the disease occurrence, the presence of immune complexes in more advanced stages might indicate the involvement of humoral immunity as a late event during the disease course.