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.

A case of hypertensive emergency with alveolar hemorrhage and thrombotic microangiopathy.

A 28-year-old woman with a 5-year history of untreated hypertension was admitted for respiratory distress, hemoptysis, and retinopathy. Computed tomography showed diffuse plaques in both lung fields. Acute kidney injury, hemolytic anemia, and thrombocytopenia were noted. Kidney biopsy showed thrombosis with fibrinoid necrosis and edematous intimal thickening and luminal narrowing of the small renal artery, indicating thrombotic microangiopathy; the majority of glomeruli were collapsed. After 8 weeks of treatment with antihypertensive drugs, serum creatinine decreased to 1.0 mg/dL, and the patient recovered. In the absence of any other underlying disease, malignant nephrosclerosis associated with a hypertensive emergency was diagnosed.

De novo posttransplant membranous nephropathy after COVID-19 vaccination 9 years after renal transplantation in a patient with polycystic kidney disease.

A 63-year-old man with polycystic kidney disease underwent kidney transplantation from his wife. Nine years later, after the first and second doses of the COVID-19 vaccination, he developed proteinuria, hematuria, and elevated C-reactive protein. Kidney biopsy 7 months after the initial appearance of proteinuria showed immunoglobulin (Ig)-G granular stain, predominantly IgG1, and spike formation in the glomerular basement membrane. Electron microscopy revealed mainly subepithelial deposits, which corresponds to membranous nephropathy (MN) stage 3 of the Ehrenreich-Churg classification indicating chronic disease, but it also showed electron-dense deposits and endothelial damage. Because a kidney biopsy was performed 1 h after renal transplantation and a biopsy of the patient's native kidney showed intact glomeruli, atypical de novo posttransplant membranous nephropathy (MN) was diagnosed, and a close relationship with COVID-19 vaccination was assumed. Clinicians should consider the involvement of COVID-19 vaccination in de novo posttransplant MN with unclear pathogenesis.

Is Podocytopathy Associated with Gross Hematuria after COVID-19 Vaccination in Patients with Immunoglobulin A Nephropathy?

We experienced three cases of a fever and subsequent severe, prolonged gross hematuria after COVID-19 vaccination. A kidney biopsy revealed immunoglobulin A (IgA) nephropathy, and electron microscopy showed two types of podocytopathy (podocyte damage): loss of foot processes from the glomerular basement membrane and foot process effacement. Mesangial interposition was also present in cases 1 and 3 but not in case 2. Podocytopathy is known to be a cause of proteinuria; however, the reactions to COVID-19 vaccination described here suggest that it may also be related to hematuria in IgA nephropathy.

Gastric Burkitt's monomorphic post-transplant lymphoproliferative disorder after kidney transplantation: A case report.

We report on a 53-year-old Japanese man diagnosed with gastric Burkitt's monomorphic post-transplant lymphoproliferative disorder (B-PTLD) after endoscopy for gastric discomfort 28 months after the patient underwent renal transplantation in Ethiopia. Serum Epstein-Barr virus (EBV) tests were negative before transplantation, but the tumor cells collected from a gastric biopsy showed positive EBV-encoded small RNAs (EBER) at B-PTLD onset. Intensive treatment started with R(rituximab)-CHOP therapy and continued with DA-EPOCH-R therapy has been effective, and relapse has not yet occurred. Burkitt lymphoma has a poor prognosis, but B-PTLD may be effectively treated with high-dose chemotherapy. This is a rare case of gastric B-PTLD in a Japanese patient.

Immunoglobulin G4-related Dacryoadenitis Successfully Treated with Baricitinib.

A 48-year-old woman visited our hospital because of bilateral lacrimal gland enlargement. Her serum immunoglobulin G4 (IgG4) level was high, and positron emission tomography-computed tomography showed significant positive findings in the bilateral lacrimal gland. A biopsy revealed a considerable increase in IgG4/CD138, leading to a diagnosis of IgG4-related dacryoadenitis. The disease did not respond to steroid therapy, so treatment was started with baricitinib because of exacerbation of the original atopic dermatitis and dacryoadenitis after the second dose of the coronavirus disease 2019 (COVID-19) vaccine. Baricitinib was effective for resolving both dermatitis and dacryoadenitis, and steroids were able to be discontinued. The IgG4 level also improved.

Autopsy of a 45-year-old Man with Liver Failure Due to Polycystic Liver Disease.

A 37-year-old man with autosomal polycystic kidney disease (ADPKD) was admitted to our hospital with a liver volume of 8,000 cm3. Hepatic arterial embolization was performed using a microcoil but was ineffective. Eight years later, the hepatomegaly progressed to liver failure and death. At autopsy, the liver weighed 21.5 kg, and the entire liver had been replaced by cysts; in the few remaining areas of liver parenchyma, microscopic, small cysts of various sizes and fibrosis were evident, with only a few normal hepatocytes observed. Hepatic arterial branches developed; however, the portal vein could not be observed.

Histologically Proven Recurrent Synovitis after Nivolumab Treatment.

A 58-year-old woman with rheumatoid arthritis was diagnosed with methotrexate-associated Hodgkin lymphoma. After receiving several chemotherapy regimens, she started nivolumab treatment. Two weeks later, she was hospitalized with worsening finger, wrist, and elbow joint pain. A synovial biopsy of the wrist joint showed villous synovial proliferation and linear infiltration of CD68-/CD3-positive T cells (with more CD8 than CD4 T cells) but no CD20-positive B cells or CD138-positive macrophages. These findings corresponded to synovitis associated with immune-related adverse events, which are induced mainly by T cells and are different from typical rheumatoid arthritis (RA), in which B cells play a central role.

Anti-factor H antibody-positive C3 glomerulonephritis secondary to poststreptococcal acute glomerulonephritis with diabetic nephropathy.

Poststreptococcal acute kidney glomerulonephritis (PSAGN) has been seen in adults in recent years, especially in patients with type 2 diabetes mellitus, and the renal prognosis has not always been good. There have been cases of PSAGN in which complete remission was not achieved and hematuria and proteinuria persisted, leading to end-stage renal disease. Previous reports showed that the patients subjected to PSAGN have an underlying defect in regulating the alternative pathway of complement, and they identified that antibodies to the C3 convertase, C3 nephritic factors (C3NeF), are involved. C3NeF stabilizes C3 convertase, sustains C3 activation, and causes C3 glomerulonephritis (C3GN). On the other hand, factor H is a glycoprotein that suppresses the overactivation of the alternative pathway by decaying the C3 convertase. Anti-factor H (aFH) antibodies interfere with factor H and cause the same activation of the alternative pathway as C3NeF. However, a limited number of reports describe the clinical course of C3GN with aFH antibodies. We encountered a 49-year-old Japanese man with type 2 diabetes mellitus. He was referred to our hospital because of his elevated serum creatinine, proteinuria, hematuria, and developed edema on both legs. He was diagnosed as PSAGN at the first kidney biopsy, and his renal function improved and edema and hematuria disappeared, but proteinuria persisted after 5 months. He was diagnosed as C3GN at the second kidney biopsy. In our case, no C3NeF was detected. However, a high titer of aFH antibodies was detected in stored serum from the initial presentation, providing a unified diagnosis of aFH antibody-positive C3GN secondary to PSAGN. He progressed to end-stage renal disease (ESRD) and hemodialysis was started. The persistence of high levels of aFH autoantibodies may have caused C3GN secondary to PSAGN due to activating the alternative complement pathway, which eventually worsened the nephropathy and led to ESRD.

Gene expression profiling of pancreatic neuroendocrine carcinoma and mixed neuroendocrine-non-neuroendocrine neoplasm.

Pancreatic neuroendocrine carcinoma (NEC) and mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) are rare pancreatic malignant tumors, and comprehensive gene analyses are scarce. In this study, six NECs and six MiNENs were collected, immunohistochemistry for synaptophysin, chromogranin A, INSM1, Ki-67, and Rb was conducted, and KRAS mutational status was examined. Among these cases, comprehensive gene expression analysis of oncogene pathways using nCounter® were performed with six NECs and four MiNENs, and those data were compared with that of three pancreatic ductal adenocarcinomas (PDACs), with that of three normal pancreatic ducts, and with each other. By dividing NEC and MiNEN cases into KRAS-mutated group and KRAS-wild group, the difference of clinicopathological data and gene expression profiling data were examined between the two groups. Compared to the data of normal pancreatic epithelium, all 13 cancer-related pathways were upregulated in PDAC, MiNEN, and NEC group with more upregulation in this order. Compared to the data of PDAC, genes of DNA Damage repair pathway was most upregulated both in NECs and MiNENs. Regarding the difference between KRAS-mutated and KRAS-wild groups, several genes were differentially expressed between the two, where MMP7 was the upregulated gene with highest p-value and NKD1 was the downregulated gene with highest p-value in KRAS-mutated group. From the extent of upregulation of 13 pathways, MiNEN was considered more progressed stage than PDAC, and NEC was considered more progressed than MiNEN. From the comparison of KRAS-mutated and KRAS-wild NECs and MiNENs, several differentially expressed genes were identified in this study.

A case of bullous pemphigoid and renal disease after dipeptidyl peptidase 4 inhibitor administration.

A 62-year-old man with type 2 diabetes was admitted because of a decrease in estimated glomerular filtration rate from 72 to 17.5 mL/min/1.73 m2 in 10 years and development of widespread bullous skin lesions. His hemoglobin A1c level had been maintained at 6.0-7.0% for 10 years with a dipeptidyl peptidase (DPP)-4 inhibitor. Skin biopsy showed typical bullous pemphigoid, and kidney biopsy showed tubulointerstitial nephritis with eosinophilic infiltration and glomerular endothelial cell proliferation. After discontinuing the DPP-4 inhibitor, skin lesions improved, and renal decline slowed. This case indicates that DPP-4 inhibitors can cause not only skin lesions but also renal disease.

IL25+ macrophages are a key determinant of treatment resistance of IL17RB+ breast cancer.

Recurrence and metastasis are resistant to multimodal treatments, and are the major causes of death in breast cancer. Accumulating evidence suggests that the IL17RB signaling pathway plays a key role in progression and metastasis of breast cancer. Clinical significance of the IL17RB positivity in tumor tissues has been also reported as a poor prognostic factor in breast cancer. However, the molecular mechanisms underlying the poor prognosis of patients with IL17RB+ breast cancer, particularly the immunological aspects, remain to be fully elucidated, and elimination of the IL17RB+ tumors has not been practically achieved in clinical settings. In this study, we identified a distinct molecular mechanism underlying the intractability of the IL17RB+ tumors through tumor biological and immunological investigation using mouse and human breast cancer cells transduced with il17rb gene. IL17RB overexpression in tumor cells confers cancer stemness, including high invasive and self-renewal abilities, and high resistance to CDK4/6 inhibitors that have been considered as a promising agent for treating breast cancer despite the limited efficacy. In the mice implanted with the IL17RB+ tumors, IL25+ macrophages (Møs) are expanded locally in tumor tissues and systemically in spleen, and promote the IL17RB+ tumor progression directly by intensifying the tumor functions, and indirectly via impairment of anti-tumor effector CTLs and NK cells utilizing the secreted IL25. Blocking IL25 with the specific mAb, however, interferes the adverse events, and successfully elicits significant anti-tumor efficacy in combination with CDK4/6 inhibitors providing better survival in murine mammary tumor models. These results suggest that the IL25+ Mø is a key determinant of building the solid treatment resistance of the IL17RB+ breast cancer. Targeting the IL17RB-IL25 axis may be a promising strategy to improve clinical outcomes in the treatment of breast cancer patients, particularly with IL17RB+ tumors.

A Case of Glomerular Microangiopathy-like Nephropathy Caused by Hyperthyroidism.

A 49-year-old Japanese woman was admitted to our hospital with weight loss of 15 kg, nephrotic-range proteinuria (4.5 g/g.Cre), and hematuria over a 6-month period. She had received two doses of the COVID-19 vaccine one year before the onset of the disease, after which the estimated glomerular filtration rate increased. Laboratory tests and other tests led to a diagnosis of hyperthyroidism, and a kidney biopsy showed thrombotic microangiopathy-like glomerular microangiopathy comprising mainly glomerular endothelial cell damage. Thiamazole (30 mg) was started for the hyperthyroidism. Three months later, the thyroid function normalized, and two months later, the proteinuria and hematuria disappeared, suggesting that COVID-19 vaccination and these events were related.

Syphilis-related Membranous Nephropathy in a 35-year-old Woman.

A 35-year-old woman was admitted for the examination of lower leg edema and proteinuria. A kidney biopsy showed membranous nephropathy (MN) with fine granular deposits of IgG along the glomerular capillary and poor spike formation, differing from primary MN in the presence of positive IgG3 and C1q. Lupus nephritis was excluded because serum complement and anti-dsDNA antibody, anti-Smith antibody, and anti-cardiolipin antibody tests were negative. The serological test for syphilis was positive, as was the Treponema pallidum hemagglutination test. The patient was diagnosed with syphilis, and the proteinuria disappeared with antibiotic treatment. In MN with positive IgG3 and C1q, syphilis nephropathy may be a differential diagnosis.

Dipeptidyl peptidase-4 inhibitor-related renal disease.

BACKGROUND: Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used to treat type 2 diabetes (T2D). Lowering blood glucose is expected also to reduce the progression of diabetic nephropathy. We experienced a patient with T2D who achieved good glycemic control with a DPP-4 inhibitor but experienced rapid deterioration of renal function. Therefore, we performed a retrospective study of similar patients treated at our hospital. METHODS: Out of 56 patients with biopsy-proven diabetic nephropathy who underwent native kidney biopsy at Toranomon Hospital from January 2018 through December 2022, we selected 22 patients who had been receiving DPP-4 inhibitors for at least 9 months at the time of kidney biopsy. Of these patients, we evaluated 16 diagnosed with class IIa diabetic nephropathy according to Tervaert's pathologic classification. The yearly estimated glomerular filtration rate (eGFR) slope in the 16 patients was arranged from the highest to the lowest slope. Ten patients with a large eGFR slope had thrombotic microangiopathy (TMA)-like lesions characterized by glomerular endothelial cell proliferation and GBM duplication on kidney biopsy (group A), whereas the remaining 6 patients did not have TMA-like lesions (group B). RESULTS: Group A had a median (interquartile range [IQR]) eGFR of 18.2 (16.2, 26.2) and a yearly median (IQR) eGFR slope of -11.2 (-17.6, -9.2) mL/min/1.73 m2 after of DPP-4 administration, whereas group B had a median (IQR) eGFR of 31.5 (21.9, 34.8) mL/min/1.73 m2 and a yearly median (IQR) eGFR slope of -1.6 (-3.1, -0.3). Renal function declined significantly more rapidly in group A than in group B, and proteinuria was higher in group A than in group B (median [IQR], 3.4 [2.6, 4.4] g/day vs 0.8 [0.4, 1.3] g/day, respectively). Five patients in group A progressed to dialysis during follow-up, but none of the patients in group B did. Median (IQR) hemoglobin A1c was 6.2 % (6.0 %, 6.6 %) in group A and 5.8 % (5.7 %, 6.6 %) in group B. CONCLUSION: DPP-4 inhibitors promote vascular endothelial regeneration, but when this effect occurs in the glomerulus, glomerular endothelial cell proliferation leads to TMA-like lesions, which may cause an increase in proteinuria and rapid decline in renal function.

Apolipoprotein E-associated Lipoprotein Glomerulo-tubulopathy.

A 32-year-old man was admitted for the evaluation of proteinuria (5.69 g/day). A light microscopic examination showed markedly dilated glomerular capillary loops with vacuolated areas in many glomeruli, and vacuolated areas were seen on peritubular capillaries in the tubulointerstitium. When electron microscopy specimens prepared by pre-fixation with glutaraldehyde and post-fixation with osmium tetroxide were used for oil red staining, the deposition was confirmed on the affected areas. A genetic analysis of apoE showed that the lipoprotein glomerulopathy was due to apoE-Sendai (Arg145Pro, p.R163P) heterozygosity, which was found in not only the patient but also his mother and twin brother.

A Case Report of Aggressive Fumarate Hydrase-deficient Renal Cell Carcinoma With Loss of HLA Antigens.

BACKGROUND: Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is a rare RCC subtype, and FH-deficient RCC may be misdiagnosed as another type of RCC, such as type 2 papillary RCC or collecting duct carcinoma. FH and 2-succinocysteine (2SC) are useful diagnostic markers for FH-deficient RCC and can be measured using immunohistochemistry (IHC). CASE REPORT: A 30-year-old female with 3-month history of fatigue and left-flank mass was diagnosed with a 20×13×10 cm left-side renal mass with massive inferior vena cava (IVC) tumor thrombus that extended into the right atrium. She underwent nephrectomy and IVC thrombectomy, and a pathological diagnosis of type 2 papillary RCC was made. Four months after the surgery, computed tomography scan showed multiple liver metastases not observed immediately after surgery. Systemic treatment with sorafenib was initiated; however, she did not respond and died 3 months after treatment. Subsequent re-review of hematoxylin and eosin-stained sections indicated morphologic characteristics consistent with FH-deficient RCC, and IHC staining was negative for FH but positive for 2SC, indicating a diagnosis of FH-deficient RCC. Further immunological analyses revealed the loss of HLA-class I, b2 microglobulin, and HLA-DR antigens in cancer cells. In addition, a few CD8-positive cytotoxic T cells and CD163-positive tumor-associated macrophages were noted. CONCLUSION: An immunosuppressive tumor microenvironment that facilitates cancer immune evasion might be associated with the rapid progression and poor prognosis in our patient. Further investigation of the tumor immune microenvironment in patients with FH-deficient RCC is warranted.

Immunoelectron microscopy findings in a patient with C3 glomerulonephritis.

We performed a kidney biopsy in a 36-year-old man to evaluate microscopic hematuria and proteinuria. Light microscopy showed increased mesangial matrix and partial swelling of the glomerular basement membrane (GBM), and immunofluorescence showed positive staining only for C3. Immunoelectron microscopy showed that gold particle-labeled C3 was localized in the electron-dense and moderately electron-dense deposits shown by electron microscopy in the mesangium, the thickened GBM near the paramesangium, and the thickened distal portion of the GBM but was not localized in the non-thickened GBM. Gold-labeled immunoglobulin G, κ, and λ were not seen. C3 glomerulonephritis was more evident in gold-labeled electron microscopy, which further clarified the localization of C3 deposition.

Linear discriminant analysis on electrocardiogram achieved classification of cardiac involvement status in amyloid light-chain amyloidosis.

OBJECTIVES: Cardiac amyloidosis (CA) is the most crucial determinant of amyloid light-chain (AL) amyloidosis patients' prognosis. We attempted cardiac involvement prediction by 12­lead electrocardiograph (ECG) and echocardiography (UCG) in AL amyloidosis patients. MATERIALS AND METHODS: Fifty patients with histologically confirmed AL amyloidosis underwent gadolinium-enhanced magnetic resonance imaging (Gd-MRI), and CA was assessed using late gadolinium enhancement. ECG and UCG parameters were measured on admission. Fisher's linear discriminant analysis was used to create a model for predicting CA using the ECG and UCG parameters. RESULTS: Prediction by five ECG parameters [QTc(B), QRS-T-angle, III-QRS, aVF-QRS, and V3-R] showed the best performance. Average sensitivity and specificity in the modeling sets, utilizing a linear discriminator based on these five variables, were 99.2 % and 96.8 % and in validation sets, 94.2 % and 90.3 %, respectively. In addition, we tested this model on an additional 26-patient cohort and survival analysis using the Kaplan-Meier method, and significant differences between CA positively predicted and negatively predicted patients were observed. CONCLUSION: Here, we suggest the application of a condensed classical multivariate statistical technique for the diagnosis of CA. It can be used as a guide to invasive endomyocardial biopsy for those in whom Gd-MRI is contraindicated and as a guide for repeat Gd-MRI in follow-up of AL amyloidosis.