Histopathological features of kidney and renal prognosis in patients with preeclampsia.

OBJECTIVE: Understanding the long-term prognosis of preeclampsia (PE) is important. Proteinuria and poor renal function persist in some PE patients, but the relationship between their histopathological findings of kidney and renal prognosis is unknown. Our objective was to clarify the relationship between clinicopathological features and renal prognosis in PE patients. STUDY DESIGN: Retrospective observational study. MAIN OUTCOME MEASURES: Seventy patients who had been referred to the Niigata University Hospital between 1977 and 2014 and were diagnosed with PE were classified into unimproved and improved groups. The unimproved group included patients whose serum creatinine level had doubled and/or whose proteinuria had persisted until the end of observation, which included three patients with end-stage kidney disease (ESKD). The improved group included patients whose serum creatinine level did not double and whose proteinuria had disappeared until the last observation. We examined and compared these patients' characteristics, clinical and laboratory findings, and renal histopathological findings from percutaneous kidney biopsies. RESULTS: There were no significant differences in the clinical backgrounds and clinical findings between the two groups during pregnancy. However, light microscopy findings of their kidney biopsies were able to identify significantly more severe duplications of the capillary loop, interstitial cell infiltration, and interstitial fibrosis in the unimproved group. CONCLUSIONS: Histopathological examination of the kidney may be a valid method for predicting the long-term prognosis of renal function and for histological a risk assessment of poor renal recovery in PE patients.

Tubulointerstitial nephritis with monotypic lympho-plasmacytic infiltrates in a patient with primary Sjögren's syndrome accompanied by IgA-type monoclonal gammopathy.

BACKGROUND: Although most cases of tubulointerstitial nephritis in paraproteinemia are monoclonal light chain deposition-mediated, interstitial nephritis as neoplastic interstitial cell infiltration has rarely been described. On the other hand, lympho-plasma-cell-rich tubulointerstitial nephritis, in which the infiltrative cells are usually polytypic, is often evident in primary Sjögren's syndrome (pSS). Herein we present a rare case of pSS in a patient who had been diagnosed as having IgA kappa-type monoclonal gammopathy of undetermined significance (MGUS) and developed tubulointerstitial nephritis with monotypic (IgA kappa) lympho-plasmacytic infiltrates. CASE PRESENTATION: A 74-year-old Japanese woman with pSS who had been diagnosed as having IgA kappa-type MGUS developed progressive renal dysfunction. Renal biopsy revealed tubulointerstitial nephritis with abundant plasma cell-rich mononuclear cell infiltrates without atypia. Immunohistochemical staining for immunoglobulins and light chains showed that most infiltrates were positive for IgA and kappa. Most of the infiltrative cells were positive for CD38 and CD138, and cells positive for CD 19 and CD 45 were also widely evident. Electron microscopy and immunofluorescence studies revealed no apparent immunological deposits in the glomeruli and tubules. Bone marrow and whole-body radiological examinations revealed no findings suggestive of multiple myeloma or lymphoma. Renal function improved rapidly with prednisolone 40 mg daily and has been maintained at the same level on low-dose prednisolone and azathioprine for 18 months. CONCLUSION: Tubulointerstitial nephritis with monotypic cell infiltrates, without immunological deposits, is a quite rare histological picture in MGUS, and might be a unique renal manifestation in patients with pSS.

Acute kidney injury in an adult patient with IgA nephropathy and chronic replicative Epstein-Barr virus infection.

Most of the adult population are infected with Epstein-Barr virus (EBV), but as EBV replication is usually under immune system control, the majority of individuals remain asymptomatic. On the other hand, some individuals continuously retain a high EBV antibody titer and a high EBV DNA load in their blood, suggesting a defect of EBV replication control. To date, only a limited number of reports have addressed the relationship between this chronic form of EBV infection and renal involvement. Here, we describe an 80-year-old woman who developed acute kidney injury shortly after an episode of mosquito bites, accompanied by a severe skin rash, which raised a suspicion of chronic EBV infection. She was subsequently diagnosed as having chronic replicative EBV infection. Renal biopsy revealed a diagnosis of IgA nephropathy with crescent formation. Although the relationship between IgA nephropathy and EBV infection has been discussed, no substantial understanding has yet emerged. The patient's characteristic clinical course suggested that the renal failure may have been partly attributable to chronic EBV infection. This case suggests that physicians may need to consider the possibility that chronic EBV infection may affect the clinical course of IgA nephropathy, or exacerbate the disease.

Severe hypermagnesemia induced by magnesium oxide ingestion: a case series.

Hypermagnesemia is generally considered an exceptional iatrogenic condition usually caused by magnesium-containing cathartics. In particular, this condition often develops when magnesium-containing cathartics are administered to elderly patients with renal insufficiency or bowel movement dysfunction. Although magnesium oxide (MgO) is widely prescribed as a laxative, serum magnesium concentration has not been examined in most cases. In this report, we present the cases of four elderly patients with constipation and symptomatic hypermagnesemia caused by MgO ingestion, one of which had a lethal course. All of the patients were older than 65 years and with renal dysfunction. In addition, they had difficulties in expressing their symptoms because of cerebrovascular events or dementia. These cases suggest that hypermagnesemia caused by magnesium-containing cathartics is more likely to develop than previously recognized and that physicians should be aware that patients with chronic kidney disease and the elderly are at risk of hypermagnesemia on magnesium administration. We recommend serum magnesium monitoring for high-risk patients after initial prescription or dose increase.

Tubulointerstitial nephritis and Fanconi syndrome in a patient with primary Sjögren's syndrome accompanied by antimitochondrial antibodies: A case report and review of the literature.

We describe a 53-year-old woman with primary Sjögren's syndrome and tubulointerstitial nephritis showing distal renal tubular acidosis and Fanconi syndrome. The patient showed high serum IgM levels and positivity for antimitochondrial antibodies, although her liver function was in normal range. According to our literature review, 75% of patients with tubulointerstitial nephritis who were positive for antimitochondrial antibodies showed Fanconi syndrome, suggesting that these antibodies may directly be associated with the pathophysiology of Fanconi syndrome.

Extracapillary proliferation and arteriolar hyalinosis are associated with long-term kidney survival in IgA nephropathy.

BACKGROUND: The Oxford classification of IgA nephropathy consists of four markers as prognosticators. We retrospectively examined the relevance of extracapillary proliferation involving cellular and fibrocellular crescents (Ex) and arteriolar hyalinosis (A) on the long-term outcome of renal function. METHODS: A total of 314 Japanese patients who were diagnosed with IgA nephropathy, with 12 months or more of follow-up period were included in this study. A total of 186 patients were with UP ≥ 0.5 g/day. Patients with diabetes mellitus or severe kidney injury (eGFR < 30 ml/min/1.73 m(2)) were excluded. The presence of Ex and A were scored 0 in the absence, and 1 in the presence, of each lesion. The end point was determined as a 50 % reduction in initial eGFR or end-stage renal disease defined as eGFR < 15 ml/min/1.73 m(2). RESULTS: In univariate analyses, the kidney survival rate was significantly lower in patients with Ex1 and A1 if UP ≥ 0.5 g/day. In the patients with UP < 0.5/day, none of the clinical and pathological parameters was determined as a risk factor. In the multivariate model including pathological parameters, Ex1 and A1 were independent risk factors for renal outcome if UP ≥ 0.5 g/day. In those patients treated with RAS-blocker or treated before introduction of methylprednisolone pulse therapy, Ex was the only independent risk factor. In multivariate analysis including clinical parameters, eGFR alone was a risk factor, due to strong correlation with other parameters. CONCLUSION: Ex and A would be associated with the renal outcome of the patients with UP ≥ 0.5 g/day.

Administration of Ferric Citrate Hydrate Decreases Circulating FGF23 Levels Independently of Serum Phosphate Levels in Hemodialysis Patients with Iron Deficiency.

BACKGROUND/AIM: Dietary phosphate intake and vitamin D receptor activator (VDRA) regulate fibroblast growth factor 23 (FGF23); iron may modulate FGF23 metabolism. We aimed to determine whether oral iron supplementation influences serum FGF23 concentration in hemodialysis (HD) patients, while excluding the effect of dietary phosphate intake. METHODS: This prospective study enrolled 27 maintenance HD patients with iron deficiency and hyperphosphatemia treated with sevelamer-HCl. The phosphate binder was changed from sevelamer-HCl to ferric citrate hydrate (FCH) to maintain constant phosphate levels. VDRA, other phosphate binders, and cinacalcet HCl were not changed. Serum intact FGF23, C-terminal FGF23 (C-term FGF23), intact parathyroid hormone (PTH), 1,25(OH)2D and other parameters were monitored for 12 weeks. RESULTS: Serum phosphate levels (5.89 ± 1.45 mg/dl at baseline, 5.54 ± 1.35 mg/dl at 12 weeks) and 1,25(OH)2D levels were unchanged. Serum ferritin levels increased from 25.6 ± 24.3 ng/ml at baseline to 55.8 ± 33.5 ng/ml at 12 weeks with FCH administration. Serum intact FGF23 and C-term FGF23 levels significantly decreased at 12 weeks compared with baseline (2,000 (1,300.0-3,471.4) to 1,771.4 (1,142.9-2,342.9) pg/ml, p = 0.01, and 1,608.7 (634.8-2,308.7) to 1,165.2 (626.1-1,547.8) RU/ml, p = 0.007, respectively); serum intact PTH levels significantly increased (96 (65-125) to 173 (114-283) pg/ml, p < 0.001). CONCLUSIONS: Oral FCH administration decreased serum intact FGF23 and C-term FGF23 levels and increased intact PTH levels; phosphate and 1,25(OH)2D levels were unchanged. Oral FCH administration to treat iron deficiency is a possible strategy for reducing serum FGF23 levels independent of phosphate and VDRA.

Ultrastructural studies of IgG4-related kidney disease.

OBJECTIVE: Ultrastructural studies of IgG4-related kidney disease (IgG4-RKD) characterized by tubulointerstitial nephritis (TIN) are limited in previous reports due to the rarity of the condition. In the present report, we performed ultrastructural examinations and assessed the pathogenesis of this disease. PATIENTS: Clinicopathological studies were conducted in eight patients diagnosed with IgG4-RKD. Routine light, immunofluorescence and electron microscopy examinations and immunohistochemical assessments of IgG4 were performed using renal biopsy samples. RESULTS: Hypocomplementemia, positive anti-nuclear antibodies and eosinophilia were confirmed in more than half of the cases. Electron dense deposits (EDDs) were frequently found in the glomeruli and interstitium. The rate of deposition was 62.5% in both mesangial areas and Bowman's capsule. EDDs were frequently detected on the tubular basement membrane (TBM) (87.5% of patients). The interstitium also contained EDDs on collagen fibers in 87.5% of the cases and on basement membrane-like materials in areas of fibrosis in 37.5% of the cases. The creatinine clearance levels were significantly lower in the patients with the latter pattern. Meanwhile, the rate of immunoglobulin and/or complement deposition on the TBM was observed in less than 37.5% of patients, and these findings were not entirely coincident with the cases of EDDs on the TBM. CONCLUSION: EDDs are frequently found in the glomeruli and interstitium in patients with IgG4-RKD; however, immunohistological studies do not provide evidence that IgG4-RKD involves TIN with immune complex nephropathy. The presence of interstitial EDDs may be related to the progression of interstitial fibrosis in the setting of IgG4-RKD.

The importance of medical interview with CKD patient in diagnoses of a family with Fabry disease.

A 47-year-old Japanese man was admitted to our hospital for evaluation of proteinuria, which was detected when he was 37 years of age. His creatinine clearance levels had fallen to 76.3 mL/min/1.73 m2. A kidney biopsy was conducted, and the patient's low plasma α-galactosidase A levels suggested Fabry disease. After genetic counseling, GLA analysis revealed a novel mutation p.L387P. Interview with the patient revealed that both his younger brother and mother suffered from cardiomyopathy and were undergoing cardiological treatment. They also were positive for proteinuria. About 30 years ago, the patient's cousin (aged 25) was diagnosed with Fabry disease. He underwent hemodialysis for 9 years until his death at 42. At that time, the patient and his brother had not been investigated for Fabry disease so their cousin could not act as a proband for the brothers. Eventually, the patient, his mother, and his brother were put on enzyme replacement therapy with agalsidase beta. As this series of cases shows, medical interviews to collate both medical and family history were essential for the discovery of Fabry disease in these patients. In addition, being a treatable genetic disorder, Fabry disease should be listed in the standard differential diagnoses of systemic and familial diseases, including unknown cause of nephropathy or cardiomyopathy, for early detection of the disorder.

Development of IgG4-related disease in a patient diagnosed with idiopathic membranous nephropathy.

We report a case of IgG4-related disease (IgG4-RD) diagnosed after 3 years of follow-up for idiopathic membranous nephropathy (MN). MN has been considered as glomerular lesion of IgG4-related kidney diseases in recent years and was diagnosed simultaneously with or after a diagnosis of IgG4-RD in previously reported cases. In the present case, IgG4-RD developed 3 years after the diagnosis of idiopathic MN, indicating a possible relationship between idiopathic MN and IgG4-RD through common underlying mechanisms of development.

A case of Epstein-Barr virus-related lymphadenopathy mimicking the clinical features of IgG4-related disease.

We report an intriguing case of Epstein-Barr virus (EBV)-related multiple lymphadenopathy that clinically mimics immunoglobulin G4-related disease (IgG4-RD). A 72-year-old woman presented with a history of asthma attacks, systemic lymphadenopathy, hypergammaglobulinemia, proteinuria, and an elevated level of serum IgG4, leading to a possible diagnosis of IgG4-RD based on current comprehensive diagnostic criteria. However, a percutaneous kidney biopsy specimen showed mild mesangial proliferative glomerulonephritis with focal membranous transformation, and there was no interstitial lesion or lymphocyte infiltration. Cervical lymph node biopsy demonstrated follicular hyperplasia associated with prominent lymphoplasmacytic infiltration in the interfollicular area. However, only a few IgG4-positive plasma cells were present. An in situ hybridization study demonstrated many EBV-infected lymphocytes in the germinal center as well as in the interfollicular area. This case illustrates the diversity of conditions associated with elevated levels of serum IgG4 and the necessity for tissue biopsy when diagnosing IgG4-RD.

A case of membranoproliferative glomerulonephritis developed over twenty years with three different findings of renal pathology.

A 31-year-old woman with proteinuria, hypocomplementemia, rheumatoid factor, and high serum polyclonal IgM concentration was admitted to our hospital for renal biopsy. She had a past history of two renal biopsies. When she was 12 years old, she developed proteinuria, microscopic hematuria, and hypocomplementemia. She was diagnosed as having 'IgM nephropathy' based on minor glomerular abnormalities as determined by light microscopy and IgM and C3 deposition in the mesangial region by immunofluorescence microscopy at the first biopsy. Despite corticosteroid treatment, her proteinuria did not improve and she discontinued regular outpatient checkups. When she was 29 years old and pregnant, she developed preeclampsia and, after delivery, a second renal biopsy was implemented. She was diagnosed as having progressed 'IgM nephropathy' with endotheliosis induced by preeclampsia. She was treated with angiotensin II receptor blocker and her proteinuria diminished; however, 1 year after the delivery, she developed proteinuria again, along with microscopic hematuria and hypocomplementemia. A third renal biopsy was conducted at 31 years of age and she was diagnosed as having membranoproliferative glomerulonephritis (MPGN) type I on the basis of diffuse mesangial proliferation, endocapillary hypercellularity with double contour of the capillary wall, and lobular formation in glomeruli, as determined by light microscopy. Immunofluorescence staining demonstrated deposits of C3, C4, C1q, and IgM in the mesangial region and capillary wall. She underwent corticosteroid therapy followed by normalization of urinalysis and serum complement level. Although she had initially been diagnosed with 'IgM nephropathy', she was finally diagnosed with secondary MPGN and was successfully treated by corticosteroid therapy.

Pentraxin-3 expression in acute renal allograft rejection.

Pentraxin-3 (PTX3) is an acute phase reactant produced by a variety of cell types at sites of local inflammation. We examined by immunohistochemistry renal biopsies from patients with acute rejection (n = 10), protocol biopsies without rejection (n = 37), and peri-operative donor biopsies of the same transplant patients (n = 94) for intra-renal expression of PTX3, and its correlation with clinical, laboratory, and histopathologic parameters. PTX3 was mainly expressed in the interstitium of renal allograft. In the non-rejection biopsies (pre- and post-reperfusion and protocol biopsies), PTX3 expression area (PTX3%) was equally maintained at a low level, whereas in the rejection biopsies, PTX3% was significantly higher (p < 0.0001). Treatment of acute rejection resulted in a significant reduction of PTX3% (p < 0.0001). PTX3% positively correlated with the degree of allograft dysfunction and acute rejection scores of Banff classification (2009). This study suggests that PTX3% may be an available histological marker of acute renal allograft rejection.

Light-microscopic characteristics of IgG4-related tubulointerstitial nephritis: distinction from non-IgG4-related tubulointerstitial nephritis.

BACKGROUND: IgG4-related disease is a multi-organ disorder characterized by a high level of serum IgG4 and dense infiltration of IgG4-positive cells into affected organs. In routine studies, however, IgG subclasses are not estimated. In the present study, we attempted to clarify the light-microscopic characteristics of IgG4-related tubulointerstitial nephritis (TIN) to facilitate distinction from non-IgG4-related TIN in specimens obtained by renal biopsy using routine staining. METHODS: In specimens from 34 cases of TIN (13 IgG4-related and 21 non-IgG4-related), 9 nephrologists independently reviewed the following histological features of interstitial lesions: (i) cell infiltration extending into the renal capsule, (ii) cell infiltration into the renal medulla, (iii) regional lesion distribution, (iv) lymphoid follicles, (v) granulomatous lesions, (vi) necrotizing angiitis, (vii) eosinophil infiltration, (viii) neutrophil infiltration, (ix) tubulitis, (x) peritubular capillaritis, (xi) storiform fibrosis and (xii) the stage of interstitial fibrosis. The modified nominal group technique was applied to obtain a consensus in the pathological interpretation. RESULTS: Consensus was successfully attained among the diagnosticians for all but one pathological feature (regional lesion distribution). Storiform fibrosis was demonstrated in 12 of 13 (92.3%) cases of IgG4-related TIN but in none of the cases of other types of TIN. Cell infiltration extending into the renal capsule was also observed only in IgG4-related TIN. Conversely, neutrophil infiltration, severe tubulitis, severe peritubular capillaritis, granulomatous lesions and necrotizing angiitis were evident only in non-IgG4-related TIN. CONCLUSIONS: This study revealed some useful and characteristic features for distinguishing IgG4-related from non-IgG4-related TIN on the basis of light-microscopic observation.

The case of BK virus infection in which it was difficult to differentiate from acute rejection.

BK virus (BKV) nephropathy is one of the major causes of allograft dysfunction or graft loss in kidney transplant recipients. Early diagnosis and timely reduction in immunosuppressant is important for proper treatment. We report a 35-yr-old male case of cadaveric renal transplantation with BK viral related tubulointerstitial nephritis complicated by acute rejection. The diagnostic biopsy showed severe inflammatory infiltrates, tubulitis, and peritubular capillaritis. Discontinuation of mycophenolate mofetil, prednisone pulse therapy, and r-globulin was successful in relieving allograft dysfunction.