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.

Successful Discontinuation of Glucocorticoid Treatment after Administration of a Calcineurin Inhibitor for Nephrotic Syndrome in a Patient with Lupus Nephritis.

Systemic lupus erythematosus was diagnosed in a patient at 43 years old. When proteinuria recurred at 57 years old, the first kidney biopsy was performed, and class IV-G (A) +V lupus nephritis was diagnosed. The prednisolone dose was increased to 40 mg/day, and cyclosporine A was introduced. After 1 year, proteinuria had decreased to 0.1 g/day. Prednisolone was discontinued three years later, and cyclosporine A was continued. Thereafter, proteinuria did not reoccur. At 67 years old, a second kidney biopsy showed complete remission of lupus nephritis. Cyclosporine A enabled permanent discontinuation of glucocorticoids in a patient with lupus nephritis.

A case of malignant nephrosclerosis occurring with serum renin in the normal range.

A 37-year-old Japanese man was admitted to our hospital for evaluation of severe hypertension and visual impairment. His serum creatinine was 4.16 mg/dL. Plasma renin activity was normal (2.7 ng/mL/h), but plasma aldosterone concentration was elevated (27.2 ng/dL). A kidney biopsy showed concentric subendothelial edematous thickening of the arterioles (onion skin pattern) with luminal narrowing or obstruction, and malignant nephrosclerosis was diagnosed. Antihypertensive therapies, including an angiotensin II receptor blocker and spironolactone, were administered and effectively preserved kidney function and normalized blood pressure. This case indicates that hyperaldosteronemia in the presence of normal renin levels might also cause malignant hypertension.

Long-term prognosis of monoclonal immunoglobulin-associated glomerular diseases with non-organized deposits: A report of 38 cases from a Japanese single center.

Monoclonal immunoglobulin (MIg)-associated glomerular diseases with non-organized deposits are rare disorders. They have recently been categorized into light chain deposit disease (LCDD), light and heavy chain deposit disease (LHCDD), heavy chain deposit disease (HCDD), proliferative glomerulonephritis with MIg deposits (PGNMID) and its light chain only variant (PGNMID-LC), and membranous glomerulopathy with light chain-restricted deposits (MG-LC). In our Japanese cohort of more than 9,500 patients who underwent renal biopsy (1979 - 2020), we evaluated clinicopathological features and long-term outcomes in 38 patients with MIg-associated glomerular diseases with non-organized deposits: LCDD (n = 9), LHCDD (n = 8), HCDD (n = 5), PGNMID-membranoproliferative glomerulonephritis (MPGN) (n = 7), PGNMID-LC (n = 2), and MG-LC (n = 7). In patients with LCDD, a low estimated glomerular filtration rate (eGFR) at biopsy, a high detection rate of urinary MIgs, a high incidence rate of multiple myeloma, and sever tubulointerstitial and vascular lesions were significant clinicopathological characteristics. Median duration of follow-up in each group was 42 - 114 months. Most patients were treated with steroid-based therapy. Patients with LCDD, LHCDD, HCDD, and MG-LC were recently treated with bortezomib-based therapy. Renal survival rate was significantly shorter for LCDD than of PGNMID and MG-LC. Patient survival rate was significantly longer for MG-LC than HCDD and PGNMID. Major causes of death were pulmonary and cardiovascular complications. Among disease groups, significant differences were observed in eGFR at biopsy, detection rates of urinary MIgs, incidence rates of multiple myeloma, severities of tubulointerstitial and vascular lesions, and long-term outcomes.

Evaluation of a newly proposed renal risk score for Japanese patients with ANCA-associated glomerulonephritis.

BACKGROUND: We determined the usefulness and prognostic ability of the renal risk score (RRS), proposed in Europe, for Japanese patients with antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN) and high myeloperoxidase (MPO)-ANCA positivity; these aspects remain to be verified. METHODS: This retrospective study was conducted on 86 Japanese patients with new, biopsy-confirmed AAGN. We calculated the RRS and analyzed the relationship between this classification, and clinicopathological features and prognosis. We also compared the predictive values between RRS for endpoints including renal death and conventional prognostic tools for patients with AAGN. RESULTS: There were 33, 37, and 16 patients in the low-, medium-, and high-risk groups, respectively. All patients were MPO-ANCA positive. The median follow-up period was 33 months; 16 (18.6%) patients progressed to end-stage renal disease (ESRD). In the high-risk group, 9/16 (56.3%) patients progressed to ESRD, and renal prognosis was significantly poorer than that in other groups (low-risk group, P < 0.001; medium-risk group, P = 0.004). In Cox multivariate regression analysis, RRS was an independent, poor renal prognostic factor (hazard ratio 5.22; 95% confidence interval 2.20-12.40; P < 0.001). The receiver-operating characteristic curves of the RRS for each endpoint were comparable with those of the 2010 histological classification and those of the severity classification of Japanese rapidly progressive glomerulonephritis. CONCLUSIONS: This is the first study to report the usefulness of the RRS for predicting renal outcomes among Japanese patients with AAGN. Our predictive value of the RRS was comparable with that of conventional prognostic tools.

Use of biologic agents and methotrexate improves renal manifestation and outcome in patients with rheumatoid arthritis: a retrospective analysis.

BACKGROUND AND PURPOSE: We examined whether advances in treatment strategies from older disease-modifying antirheumatic drugs (DMARDs) to new biologic agents and methotrexate improved renal complications and outcome in patients with rheumatoid arthritis (RA). METHODS: We reviewed records of 156 patients with RA who underwent kidney biopsy at our institute between January 1990 and December 2019. All patients were assigned to one of three periods: period 1, 1990-1999 (n = 48); period 2, 2000-2009(n = 57); period 3, 2010-2019 (n = 51). RESULTS: Membranous nephropathy, nephrosclerosis, AA-amyloidosis, and IgA nephropathy were the four major renal manifestations of RA. AA-amyloidosis was diagnosed by kidney biopsy in 21 patients: period 1, 7 patients (15%); period 2, 10 patients (18%); and period 3, 4 patients (8%). The 4 patients in period 3 were in the years 2010-2014, and no new case of AA-amyloidosis was recorded from 2015 to 2019. In all 21 of the patients with AA-amyloidosis, neither a biologic agent nor methotrexate was administered. Fifteen of the 21 patients required dialysis, and 13 died in periods 1-3 because of amyloid-related cardiac dysfunction less than 2 years after the initiation of dialysis. Two of them are doing well using biologic agent despite dialysis. The remaining three patients who received a biologic agent or methotrexate does not progress to end-stage renal failure. In addition, the other renal complications showing progression to dialysis also decreased over time. CONCLUSION: Advances in treatment strategies have improved renal outcome and reduced mortality in patients with RA.

Renal epithelial and stromal tumor with a multiple cystic lesion localized in the upper portion of the right kidney.

A 60-year-old Japanese woman was admitted because of the polycystic mass with right flank pain localized in the upper portion of the right kidney. Right nephrectomy was performed because the mass lesion had continuously increased in size over the past 10 years. A surgical specimen showed histology consistent with a mixed epithelial and stromal tumor, which is closely related to multilocular cystic nephroma, and was diagnosed by a defined capsule between the cystic mass lesion and normal renal tissue by CT and MRI, and histology. Localized renal cystic disease that does not have a capsule was excluded from differential diagnosis.

Abatacept Improves Intractable Protein-Losing Enteropathy Secondary to AA Amyloidosis in a Patient With Rheumatoid Arthritis.

A 71-year-old Japanese woman with a history of rheumatoid arthritis of 50 years' duration was admitted to our hospital with refractory diarrhea. Endoscopic biopsy revealed AA amyloid deposition in the large intestine. Although the patient had been prescribed 5 tumor necrosis factor inhibitors over the past 10 years, rheumatoid arthritis was poorly controlled, with a Disease Activity Score 28 using C-reactive protein score of 6.52 on admission. Treatment with tocilizumab (8 mg/kg every 2 weeks) was initiated, but this was ineffective. After 3 months, abatacept (cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin) was initiated (750 mg/mo) and the patient's diarrhea began to improve. After 3 months of abatacept treatment, serum albumin, C-reactive protein, and serum amyloid A levels had all decreased to within normal ranges. After 3 years of abatacept treatment, a repeat biopsy of the large intestine revealed a marked improvement in amyloid deposition. Interleukin 6 is a key factor in AA amyloid formation, but this case suggests that T-cell activation increases the production of cytokines (including interleukin 6) via a mechanism involving cytotoxic T-lymphocyte-associated antigen 4, resulting in a second key factor of AA amyloid formation.

Clinicopathological features and outcomes of diabetic kidney disease with extracapillary hypercellularity: a Japanese single-center experience.

BACKGROUND: The prognostic significance of glomerular extracapillary hypercellularity (EXHC) in diabetic kidney disease (DKD) is unclear. The aim of this study was to investigate the clinicopathological features and outcomes of DKD patients with EXHC. METHODS: We studied 70 cases of renal biopsy-confirmed type 2 DKD that were diagnosed between 2004 and 2014 and compared the clinicopathological features and outcomes of 22 patients with EXHC (EXHC group) with those of 48 patients without EXHC (control group). All of the patients were Japanese. We assessed the renal biopsy specimens based on the Renal Pathology Society classification system. Clinical and laboratory data were collected at the time of the renal biopsy, and renal outcomes were assessed based on progression to end-stage renal disease (ESRD) requiring renal replacement therapy. The median duration of the observation period was 3 years. RESULTS: In pathological features, nodular sclerosis (Kimmelstiel-Wilson lesions) was observed more frequently in the EXHC group than in the control group (63.6% vs. 35.4%, P = 0.027). There were no significant intergroup differences in clinical features or renal outcomes. Univariate and multivariate Cox regression analyses of all patients showed that a high level of proteinuria, a low initial eGFR, and severe interstitial inflammation were poor prognostic factors. CONCLUSIONS: EXHC is related to nodular sclerosis, which is a known risk factor for ESRD. Careful observation is needed during the follow-up of DKD patients with EXHC, although there were no significant differences in renal outcomes between the EXHC and control groups.

Membranous nephropathy with solitary polyclonal IgA deposition: A case report and literature review.

A 60-year-old man presented with nephrotic syndrome (NS). Light microscopy of renal biopsy specimens showed minor glomerular abnormalities, while immunofluorescence microscopy revealed solitary polyclonal granular IgA deposition along the glomerular capillary walls. Electron microscopy showed small amounts of electron-dense deposits in the subepithelial area, but not in the mesangial area. In this patient, apparent underlying disease was not found during the 3-year follow-up, and low-dose prednisolone was effective in the treatment of NS. To our knowledge, there is only one case report of membranous nephropathy with clinicopathological features similar to our case.

Disappearance of a thrombotic microangiopathy-like glomerular lesion in a patient with a placental site trophoblastic tumor after hysterectomy.

A 32-year-old woman presented with amenorrhea after a normal childbirth and subsequently developed nephrotic syndrome. Renal biopsy showed a thrombotic microangiopathy (TMA)-like glomerular lesion with deposits of immunoglobulins, complements, and fibrinogen. Increased serum levels of the beta subunit of human chorionic gonadotropin, abnormal uterine findings from imaging studies, and endometrial biopsy findings suggested gestational trophoblastic disease. She was diagnosed with a placental site trophoblastic tumor (PSTT) after hysterectomy and, following treatment, her proteinuria disappeared. Follow-up renal biopsy showed the disappearance of the TMA-like lesion. To our knowledge, this is the first case report of the pathological remission of renal disease associated with PSTT.

Clinicopathological and long-term prognostic features of membranous nephropathy with crescents: a Japanese single-center experience.

BACKGROUND: Three recent studies from the United States and China reported the clinicopathological features and short-term prognosis in patients with membranous nephropathy (MN) and crescents in the absence of secondary MN, anti-glomerular basement membrane (GBM) antibodies, and anti-neutrophil cytoplasmic antibodies (ANCA). METHODS: We compared clinicopathological and prognostic features in 16 MN patients with crescents (crescent group) and 38 MN patients without crescents (control group), in the absence of secondary MN, anti-GBM antibodies, and ANCA. Median follow-up periods in the crescent and control groups were 79 and 50 months, respectively. RESULTS: Decreased estimated glomerular filtration rates (<50 mL/min/1.73 m2), glomerulosclerosis, and moderate-to-severe interstitial fibrosis were more frequently observed in the crescent group than in the control group (P = 0.043, P = 0.004, and P = 0.035, respectively). Positive staining rates for glomerular IgG2 and IgG4 were significantly different between the 2 groups (P = 0.032, P = 0.006, respectively). Doubling of serum creatinine during follow-up was more frequently observed in the crescent group than in the control group (P = 0.002), although approximately two-thirds of patients in the crescent group were treated with immunosuppressive therapy. Crescent formation and interstitial fibrosis were risks for doubling of serum creatinine [hazard ratio (HR) = 10.506, P = 0.012; HR = 1.140, P = 0.009, respectively]. CONCLUSIONS: This is the first Japanese study demonstrating significant differences in clinicopathological and prognostic features between the 2 groups. Most patients in the crescent group may develop a long-term decline in renal function despite immunosuppressive therapy.

Effects of Denosumab on Bone Metabolic Markers and Bone Mineral Density in Patients Treated with Glucocorticoids.

Objective We performed a prospective study to determine the efficacy and safety of denosumab on bone metabolic indices and bone mineral density (BMD) in 29 patients receiving long-term glucocorticoids (GCs) who had clinical risk factors for fracture. Methods Among these patients, 16 had systemic lupus erythematosus (SLE), 6 RA, 4 other autoimmune diseases, and 3 renal diseases. All patients received donosumab 60 mg at baseline and 6 months. Serum N-terminal cross-linked telopeptide of type I collagen (NTX) and bone-specific alkaline phosphatase (BAP) levels were measured as bone metabolic indices. BMD at the lumbar spine (LSBMD) and femoral neck (FNBMD) were measured using dual energy X-ray absorptiometry and expressed as a percentage of the young adult mean (%YAM). Results Denosumab therapy significantly reduced serum NTX and BAP levels from baseline after 12 months (from 19.2 to 13.9 nmol BCE/L; from 11.9 to 9.2 U/L, respectively). In 18 patients treated with bisphosphonates before the start of denosumab therapy, the improvements in the LSBMD and FNBMD values were 1.5%YAM/year and 1.1%YAM/year, respectively. The LSBMD and FNBMD values were both significantly higher 12 months after denosumab therapy (3.5%YAM/year and 3.0%YAM/year, respectively). The LSBMD gain was significantly higher after denosumab therapy than during bisphosphonate therapy. No fractures were observed in any patients during denosumab therapy. Conlusion Denosumab is effective and safe in preventing bone resorption and BMD loss in patients treated with long-term GCs for inflammatory diseases. This is the first study showing a significant increase in not only LSBMD but also FNBMD in GC-induced osteoporosis after denosumab therapy.