Project description:Infiltration by IgG-positive plasma cells is a common finding in tubulointerstitial nephritis. Indeed, it has been thought that CD138-positive mature plasma cells secrete mainly IgG, and the occurrence of tubulointerstitial nephritis with CD138-positive plasma cells secreting IgM has rarely been reported. Routine immunofluorescence of fresh frozen sections is considered the gold standard for detection of immune deposits. However, the immunoenzyme method with formalin-fixed, paraffin-embedded sections is superior for detecting IgM- or IgG-positive cells within the renal interstitium, thus histologic variants may often go undetected. We recently discovered a case of tubulointerstitial nephritis showing IgM-positive plasma cell accumulation within the interstitium. To further explore the morphologic and clinical features of such cases, we performed a nationwide search for patients with biopsy-proven tubulointerstitial nephritis and high serum IgM levels. We identified 13 patients with tubulointerstitial nephritis and IgM-positive plasma cell infiltration confirmed with the immunoenzyme method. The clinical findings for these patients included a high prevalence of distal renal tubular acidosis (100%), Fanconi syndrome (92%), and anti-mitochondrial antibodies (82%). The pathologic findings were interstitial nephritis with diffusely distributed CD3-positive T lymphocytes and colocalized IgM-positive plasma cells, as well as tubulitis with CD3-positive T lymphocytes in the proximal tubules and collecting ducts. Additionally, levels of H+-ATPase, H+, K+-ATPase, and the HCO3--Cl- anion exchanger were markedly decreased in the collecting ducts. We propose to designate this group of cases, which have a common histologic and clinical form, as IgM-positive plasma cell-tubulointerstitial nephritis.
Project description:Isolated or dominant tubulointerstitial lupus nephritis is rare. Here, we reported a 67-year-old man diagnosed with systemic lupus erythematosus (SLE) based on clinical and laboratory criteria, who was showing impaired renal function and non-nephrotic range proteinuria in the past 2 years. Renal biopsy showed almost normal glomeruli, but the tubulointerstitium showed "storiform" pattern with interstitial infiltration of IgG3 predominant plasma cells. Immunofluorescence showed linear and granular staining of IgG and C1q along TBM and interstitium. He started on medium dose of oral steroids and mycophenolate mofetil, which were gradually tapered. As a result, his renal function improved over a few days. Now, he continued on low dose steroids and mycophenolate mofetil with no evidence of relapse.
Project description:IntroductionFibrillary glomerulonephritis (FGN) is a rare disease with unknown pathogenesis and a poor prognosis. Until now, the diagnosis of this disease has required demonstration of glomerular deposition of randomly oriented fibrils by electron microscopy that are Congo red negative and stain with antisera to Igs. We recently discovered a novel proteomic tissue biomarker for FGN, namely, DNAJB9.MethodsIn this work, we developed DNAJB9 immunohistochemistry and tested its sensitivity and specificity for the diagnosis of FGN. This testing was performed on renal biopsy samples from patients with FGN (n = 84), amyloidosis (n = 21), a wide variety of non-FGN glomerular diseases (n = 98), and healthy subjects (n = 11). We also performed immunoelectron microscopy to determine whether DNAJB9 is localized to FGN fibrils.ResultsStrong, homogeneous, smudgy DNAJB9 staining of glomerular deposits was seen in all but 2 cases of FGN. The 2 cases that did not stain for DNAJB9 were unique, as they had glomerular staining for IgG only (without κ or λ) on immunofluorescence. DNAJB9 staining was not observed in cases of amyloidosis, in healthy subjects, or in non-FGN glomerular diseases (with the exception of very focal staining in 1 case of smoking-related glomerulopathy), indicating 98% sensitivity and > 99% specificity. Immunoelectron microscopy showed localization of DNAJB9 to FGN fibrils but not to amyloid fibrils or immunotactoid glomerulopathy microtubules.ConclusionDNAJB9 immunohistochemistry is sensitive and specific for FGN. Incorporation of this novel immunohistochemical biomarker into clinical practice will now allow more rapid and accurate diagnosis of this disease.
Project description:We report a rare cause of rapidly progressive renal failure associated with low complement, positive ANA but negative anti DS-DNA. A renal biopsy demonstrated tubulointerstitial nephritis with positive immunoglobulin staining involving the interstitium and tubular basement membrane but glomerular sparing. A review of the literature and differential diagnosis are discussed.
Project description:Uncertainty exists regarding the association between diet and acute tubulointerstitial nephritis. Dietary factors served as exposures, including intake of alcohol, beef, non-oily fish, fresh fruit, oily fish, dried fruit, coffee, salad/raw vegetable, cereal, tea, water, salt, cooked vegetable, cheese, poultry, pork, Lamb/mutton, bread, and processed meat were extracted from the UK Biobank. Acute tubulointerstitial nephritis served as the outcome extracted from the FinnGen biobank. The 3 main methods of this analysis were weighted median, inverse-variance-weighted (IVW), and MR-Egger methods. The heterogeneity was measured employing Cochran Q test. The MR-PRESSO method was employed to identify possible outliers. The robustness of the IVW method was evaluated by employing the leave-one-out analysis. According to the IVW method, processed meat intake (OR = 0.485; P = .00152), non-oily fish intake (OR = 0.396; P = .0454), oily fish intake (OR = 0.612; P = .00161), and dried fruit intake (OR = 0.536; P = .00648) reduced the risk of acute tubulointerstitial nephritis. Other dietary factors were not shown to be causally related to acute tubulointerstitial nephritis. This study revealed that intake of processed meat, non-oily fish, oily fish, and dried fruit all decreased the risk of acute tubulointerstitial nephritis.
Project description:BackgroundHuman parvovirus B19 (B19V) causes glomerulopathy or microangiopathy, but not tubulopathy. We experienced an 11-year-old girl with spherocytosis who developed acute kidney injury on a primary infection of B19V. She presented with anuria, encephalopathy, thrombocytopenia, and coagulopathy, along with no apparent aplastic crisis.MethodsContinuous hemodiafiltration, immunoglobulin, and intensive therapies led to a cure.ResultsA kidney biopsy resulted in a histopathological diagnosis of tubulointerstitial nephritis without immune deposits. The virus capsid protein was limitedly expressed in the tubular epithelial cells with infiltrating CD8-positive cells.ConclusionsViral and histopathological analyses first demonstrated B19-infected tubulointerstitial nephritis due to the aberrant viremia with hereditary spherocytosis.
Project description:BackgroundSacituzumab govitecan is an antibody-drug conjugate that is FDA approved for refractory metastatic triple-negative breast cancer. It targets the human trophoblastic cell-surface antigen 2 (Trop-2) with SN-38, a topoisomerase I inhibitor, attached to the antibody [1]. SN-38 breaks DNA strands and induces tumor apoptosis [2]. Acute kidney injury (AKI) is one of its adverse effects mainly prerenal due to gastrointestinal toxicity, but it has not been reported to cause acute tubulointerstitial nephritis (ATIN).Case presentationThis report describes a rare adverse effect of sacituzumab govitecan, the approach to diagnosing the etiology of the patient's AKI, and the mechanism by which sacituzumab govitecan causes ATIN. A woman with metastatic ER positive, PR positive, HER2 negative breast cancer who was initiated on sacituzumab govitecan presents with vomiting and diarrhea, and findings of nephrotic-range proteinuria, negative anti-PLA2R antibody, and severe AKI requiring hemodialysis. She underwent kidney biopsy and pathology showed ATIN characterized by patchy interstitial inflammation alongside tubular injury without glomerular and vascular involvement. With intermittent renal replacement therapy, furosemide challenge, and a course of prednisone, the patient's kidney function recovered.ConclusionsSacituzumab has a high affinity for Trop-2 protein which is also expressed within the collecting ducts, and to a lesser extent, the proximal tubule. Individuals, such as this patient, who express a homozygous genotype for UGT1A1*28 allele are at increased risk for AKI from sacituzumab govitecan due to decreased glucuronidation of SN-38.
Project description:Acute tubulointerstitial nephritis (ATIN) is a common cause of acute kidney injury. Although haematuria is a risk factor for the development of renal disease, no previous study has analyzed the significance of haematuria in ATIN. Retrospective, observational analysis of 110 patients with biopsy-proven ATIN was conducted. Results: Haematuria was present in 66 (60%) ATIN patients. A higher percentage of ATIN patients with haematuria had proteinuria than patients without haematuria (89.4% vs. 59.1%, p = 0.001) with significantly higher levels of proteinuria (median (interquartile range) protein:creatinine ratio 902.70 (513-1492) vs. 341.00 (177-734) mg/g, p <0.001). Moreover, those patients with more haematuria intensity had a higher urinary protein:creatinine ratio (1352.65 (665-2292) vs. 849.60 (562-1155) mg/g, p = 0.02). Those patients with higher proteinuria were more likely to need renal replacement therapy (22.7 vs. 0%, p = 0.03) and to suffer relapse (4 vs. 0%, p = 0.03). At the end of follow up, haematuric ATIN patients had higher serum creatinine levels (3.19 ± 2.91 vs. 1.91 ± 1.17 mg/dL, p = 0.007), and a trend towards a higher need for acute dialysis (7 vs. 1%, p = 0.09) and renal replacement therapy (12.1 vs. 2.3%, p = 0.12). Haematuria is common in ATIN and it is associated with worse renal function outcomes.