Demographic, clinical characteristics and treatment outcomes of immune-complex membranoproliferative glomerulonephritis and C3 glomerulonephritis in Japan: A retrospective analysis of data from the Japan Renal Biopsy Registry.

The reclassification of membranoproliferative glomerulonephritis (MPGN) into immune-complex MPGN (IC-MPGN) and C3 glomerulopathy (C3G) based on immunofluorescence findings in kidney biopsies has provided insights into these two distinct diseases. C3G is further classified into dense deposit disease and C3 glomerulonephritis (C3GN) based on electron micrographic findings. Although these diseases have poor outcomes, limited Japanese literature confined to small, single-center cohorts exist on these diseases. We retrospectively analyzed 81 patients with MPGN type I and III from 15 hospitals in the Japan Renal Biopsy Registry to compare demographic, clinical characteristics and treatment outcomes of patients with IC-MPGN to those with C3GN. Of the 81 patients reviewed by immunofluorescence findings in kidney biopsies, 67 patients had IC-MPGN and 14 patients had C3GN. Age at diagnosis and systolic and diastolic pressure were higher and proteinuria and impaired renal function were significantly more prevalent in patients with IC-MPGN than those with C3GN. About 80% of the patients in both groups were treated with immunosuppressive therapy. At last follow-up (median 4.8 years), complete remission rate of proteinuria was significantly higher in patients with C3GN (64.3%) than in those with IC-MPGN (29.9%; P = 0.015). The renal survival rate was lower in patients with IC-MPGN when compared to C3GN (73.1% vs. 100%; log-rank, P = 0.031). Systolic blood pressure and renal function at baseline were independent predictors of progression to end-stage kidney disease. The overall prognosis of patients with C3GN is more favorable than for patients with IC-MPGN.

Membranous nephropathy that first presented in pregnancy.

A 37-year-old woman at 17 weeks of gestation who was first noted to have proteinuria and microscopic hematuria at 13 weeks of gestation was admitted to our hospital with proteinuria that progressed to nephrotic syndrome (NS). Despite the treatment with prednisolone, including methylprednisolone pulse therapy, the NS worsened. The patient underwent an elective abortion at 21 weeks of gestation, and the NS then went into partial remission. A renal biopsy revealed membranous nephropathy (MN). There was no evidence of secondary MN. This is the first reported case of subclinical idiopathic MN that first developed in pregnancy.

Sialylation determines the nephritogenicity of IgG3 cryoglobulins.

Monoclonal 6-19 IgG3 anti-IgG2a rheumatoid factor derived from lupus-prone MRL-Fas(lpr) mice can induce GN and cryoglobulinemia, but the features that confer nephritogenic potential are not completely understood. Asparagine-linked oligosaccharide chains of 6-19 IgG3 mAb are poorly galactosylated and hardly sialylated, possibly contributing to the pathogenic potential of 6-19 IgG3 rheumatoid factors. Here, we used the 6-19 model of cryoglobulin-associated GN to define the relative contributions of galactosylation and sialylation, in relation to cryoglobulin activity, to the nephritogenic potential of IgG3 antibodies. We generated one highly sialylated and two distinct more galactosylated 6-19 IgG3 rheumatoid factor variants. Although the mere extent of galactosylation had no effect on either the cryogenic and nephritogenic activities of 6-19 IgG3 rheumatoid factor, terminal sialylation attenuated the nephritogenic potential of 6-19 IgG3 by limiting its cryoglobulin activity. These data suggest a protective role of IgG sialylation against the development of cryoglobulin-mediated GN, highlighting the anti-inflammatory activity of sialylated IgG antibodies.

Renal disease in the elderly and the very elderly Japanese: analysis of the Japan Renal Biopsy Registry (J-RBR).

BACKGROUND AND OBJECTIVES: Data regarding renal disease in the elderly (age ≥65 years old) and very elderly (age ≥80 years old) Japanese are extremely limited. The aim of this study was to examine the causes of renal disease and their clinical presentations in elderly patients who underwent renal biopsy. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: From July 2007 to November 2011, all of the elderly native renal biopsy patients who had been registered in the Japan Renal Biopsy Registry (J-RBR; 2802 including 1596 males and 1206 females) were identified. Their data were compared with a control group of 7416 patients who ranged in age from 20 to 64 years old and were registered on the J-RBR over the same period. In addition, the clinical and pathological classifications of 276 very elderly patients were also analyzed. RESULTS: The indications for biopsy were nephrotic syndrome (NS) in 36.2 and 50.7 % of the elderly and the very elderly patients, chronic nephritic syndrome in 31.8 and 17.4 %, and acute kidney injury including rapidly progressive glomerulonephritis in 18.6 and 22.5 %, respectively. Primary glomerular disease was the most frequent diagnosis, followed by MPO-ANCA-positive nephritis, IgA nephropathy (IgAN), and diabetic nephropathy. In primary GN including IgAN, membranous nephropathy (MN) was the most frequent histological type, followed by IgAN and minor glomerular abnormalities. A comparison with the control group showed that MN, MPO-ANCA-positive nephritis, and amyloid nephropathy were more common in the elderly (P < 0.001), and IgAN was less common (P < 0.001). As for nephrotic syndrome in the elderly, MN was the most common histological type, followed by minimal change NS, diabetic nephropathy, amyloid nephropathy, and focal segmental glomerulosclerosis. There was a significant discrepancy between the urinary protein/creatinine ratio and daily proteinuria after the 7th decade of life. CONCLUSIONS: Renal biopsy is a valuable diagnostic tool, even in elderly and very elderly Japanese patients. In the future, modified clinical guidelines for elderly renal disease should be developed.

Effect of renal impairment on the pharmacokinetics of memantine.

The effect of renal impairment on the pharmacokinetics of a single oral dose of memantine (10 mg) was determined in Japanese subjects. Subjects were assigned to four groups based on baseline creatinine clearance (CL(CR)): normal renal function (> 80 mL/min, n = 6), and mild (50 to ≤ 80 mL/min, n = 6), moderate (30 to < 50 mL/min, n = 6), and severe renal impairment (5 to < 30 mL/min, n = 7). Mean memantine maximum plasma concentration (C(max)) was similar in the groups (12.66, 17.25, 15.75, and 15.83 ng/mL, respectively), as was mean time to C(max) (6.2, 5.2, 4.3, and 5.4 h, respectively). However, exposure to memantine determined from mean area under the plasma concentration-time curve was 1.62-, 1.97-, and 2.33-times higher in subjects with mild, moderate, and severe renal impairment, respectively, as compared to controls with normal renal function. Mean memantine plasma elimination half-life increased according to increasing renal impairment (61.15, 83.00, 100.13, and 124.31 h, respectively), while mean cumulative urinary recovery of unchanged memantine in 72 h after dosing decreased according to increasing renal impairment (33.68%, 33.47%, 23.60%, and 16.17%, respectively). These results are the same as those in the previous study on caucasian individuals, when compared per body weight. It is suggested that the dose of memantine should be halved in patients with renal impairment.

Granulomatous interstitial nephritis in a renal allograft.

We describe a middle-aged woman in whom granulomatous interstitial nephritis (GIN) developed in a renal allograft. She had undergone bowel resection due to an uncertain diagnosis of active granulomatous bowel disease 30 years earlier. Thereafter, frequent hyperoxaluria as well as calcium oxalate stone and recurrent urinary tract infections had resulted in a progressive deterioration in kidney function over a period of 20 years. She underwent living donor kidney transplantation; however, her kidney function progressively deteriorated, despite transplantation. A biopsy of the renal allograft revealed GIN with granulomatous vasculitis accompanied by calcium oxalate crystals. These as well as the laboratory findings indicated a diagnosis of sarcoidosis. We considered that the aggravated granulomatous inflammation on the allograft was caused by recurrent sarcoidosis accompanied by hyperoxaluria.

Localization of nephritis-associated plasmin receptor in acute poststreptococcal glomerulonephritis.

The nephritis-associated plasmin receptor is a recently identified nephritogenic antigen associated with acute poststreptococcal glomerulonephritis and proposed to play a pathogenic role, but its precise glomerular localization in acute poststreptococcal glomerulonephritis has not been elucidated. We therefore analyzed renal biopsy sections from 10 acute poststreptococcal glomerulonephritis patients by using immunofluorescence staining with anti-nephritis-associated plasmin receptor antibody and various markers of glomerular components. Nephritis-associated plasmin receptor was detected in the glomeruli of all patients, and double staining for nephritis-associated plasmin receptor and collagen IV showed nephritis-associated plasmin receptor to be predominantly on the inner side of the glomerular tufts. Nephritis-associated plasmin receptor-positive areas within glomerular tufts were further characterized with markers for neutrophils, mesangial cells, endothelial cells, and macrophages. In 6 of the patients, nephritis-associated plasmin receptor staining was seen mainly in neutrophils and to a lesser degree in mesangial and endothelial cells. In the other 4 patients, nephritis-associated plasmin receptor staining was seen mainly in mesangial cells and to a lesser degree in neutrophils and endothelial cells. In all patients, macrophages showed little staining. Elevated plasmin activity in glomerular neutrophils was identified by combining in situ zymography staining for plasmin activity and immunofluorescence staining for neutrophils. The glomerular localizations of nephritis-associated plasmin receptor and another nephritogenic antigen, streptococcal pyrogenic exotoxin B, were compared by double immunofluorescence staining and found to be similar. These findings indicate the nephritogenic potential of nephritis-associated plasmin receptor and offer valuable information with respect to the pathogenic mechanism of acute poststreptococcal glomerulonephritis.

Causal relationships between esophageal squamous cell carcinoma and nephrotic syndrome.

We present a case of membranous nephropathy (MN) associated with esophageal squamous cell carcinoma (ESCC) with a high serum level of squamous cell carcinoma antigen (SCC). ESCC reached complete response (CR) for radiotherapy, with a partial remission of the proteinuria and decreased serum SCC levels. Six months after radiotherapy, the ESCC recurred, and the patient was treated with endoscopic mucosal resection (EMR), achieving a pathologic CR and disappearance of proteinuria and normalized serum SCC levels. The correlation of proteinuria and the serum level of SCC indicates that SCC could be a pathogenic antigen, responsible for the pathogenesis of MN in this patient.

MPO-ANCA crescentic glomerulonephritis complicated by membranous nephropathy: MPO demonstrated in epimembranous deposits.

An elderly woman presented with haematuria and proteinuria accompanied by elevated serum myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibodies (MPO-ANCA). A renal biopsy revealed mild mesangial proliferation with fibrocellular crescent formation and a membranous glomerular lesion. Immunofluorescence microscopy using FITC-labelled rabbit anti-human MPO antibodies revealed granular MPO deposition along the glomerular capillary walls (GCW) with a staining profile similar to that of glomerular IgG deposition. The one-year follow-up renal biopsy revealed minimal IgG and undetectable MPO deposition. Both MPO and MPO-ANCA might have been responsible for the IgG immune depositions along the GCW in this patient.

[Management of chronic kidney disease--preventing the progression of renal disease].

Intraglomerular hypertension, and glomerular hypertrophy, leading to glomerular scarring are suggested to have an effect on the progression in chronic kidney disease, unrelated to the initial cause of kidney injury. Tubulointerstitial disease is another factor, which may affect the prognosis. Strategies to prevent or minimize the progression of kidney disease consist of treating these disease-worsening mechanisms, including smoking cessation, treatment of hyperlipidemia, sodium and protein restriction, antihypertensive therapy, inhibition of renin-angiotensin-aldosterone system, and treatment of anemia. Studies in experimental animals and humans suggest that these therapies are effective to prevent the progression in chronic kidney disease and there are some evidences that these therapies have benefits in the patients with chronic kidney disease.

Lupus nephritis associated with positive MPO-ANCA in a patient with underlying autoimmune hemolytic anemia.

A 19-year-old female was admitted with general malaise and systemic edema. She had been diagnosed as having autoimmune hemolytic anemia (AIHA) eight years earlier and was successfully managed with oral prednisolone. During the current admission, she was diagnosed as having systemic lupus erythematosus (SLE) based on the presence of renal involvement, hematological abnormalities, and antinuclear and anti-double-stranded DNA antibodies, along with a recurrence of AIHA; her serology revealed a high myeloperoxydase-antineutrophil cytoplasmic antibody (MPO-ANCA) titer. She was treated with prednisolone (50 mg day(-1)), but her renal function started to deteriorate. She responded to treatment with hemodialysis, plasmapheresis, and methylprednisolone pulse therapy; her MPO-ANCA titer and renal function improved. Treatment with intravenous cyclophosphamide gradually suppressed her AIHA and SLE activity. A renal biopsy revealed a diffuse proliferative lupus nephritis (class IV-G (A)) with necrotizing crescentic glomerulonephritis that was presumed to be associated with MPO-ANCA. The association of MPO-ANCA with SLE in this refractory case is discussed.

Elderly onset systemic lupus erythematosus (SLE) presenting with disseminated intravascular coagulation (DIC).

We describe an unusual case of elderly onset systemic lupus erythematosus (SLE) that presented with disseminated intravascular coagulation (DIC). An 86-year-old man who complained of general malaise was admitted for evaluation and treatment of thrombocytopenia. He was diagnosed as having SLE and DIC based on the criteria of the American College of Rheumatology for SLE (renal involvement, hematological abnormalities, and positivity for antinuclear antibody and lupus anticoagulant) and the criteria for DIC presented by the subcommittee on DIC of the ISTH (a large increase of fibrin degradation products [3 points] and a platelet count <50 x 10(3)/ml [2 points], resulting in a score of 5; a score > or =5 is compatible with DIC). The patient was treated with corticosteroid therapy (30 mg/day); the DIC and SLE remitted, and his renal function improved, but he developed pulmonary tuberculosis. Timely diagnosis, appropriate treatment, and an awareness of the potential for serious infections are of utmost importance when dealing with patients with elderly onset SLE.

[Focal segmental glomerulosclerosis in a patient with polycythemia vera].

Herein we describe the case of a patient with focal segmental glomerulosclerosis (FSGS) following polycythemia vera (PV) on whom hemodialysis was started 7 years later. A 66-year-old woman who had been treated for PV with hydroxyurea and phlebotomy for three years was referred to our hospital because of nephrotic syndrome. Renal biopsy performed at her local hospital revealed FSGS. Although she had received prednisolone at an initial dose of 45 mg/day, no significant improvement of proteinuria was achieved. The dose of prednisolone was tapered because the second renal biopsy revealed sclerosing glomerulopathy. We considered that FSGS was associated with PV because renal hemodynamic alterations in PV could result in FSGS as in any other secondary FSGS and there was no proteinuria at the initial detection of PV. On January 29, 1999, she developed massive proteinuria (9.6 g/day) and the findings of the third renal biopsy worsened in comparison with that of the first renal biopsy. Thereafter, hydroxyurea or ranimustine was used in treating PV at an outpatient clinic. However severe thrombocytosis was difficult to control, and progressive renal dysfunction finally necessitated hemodialysis on January 18, 2005. In conclusion, physicians should be aware of the risk of progressive renal failure in patients with FSGS following PV, particularly in patients with persistent thrombocytosis.

Microscopic polyangiitis after silicone breast implantation.

We describe the case of a patient who developed microscopic polyangiitis (MPA) after silicone breast implantation. A 60-year-old woman who had undergone silicone breast implantation was admitted to our hospital with complaints of general malaise and hematoproteinuria. She was diagnosed as having MPA with evidence of acute progressive renal failure, pulmonary hemorrhage, and positivity for myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA). A renal biopsy showed severe necrotizing and crescentic glomerulonephritis with arteriolitis. The patient received high-dose steroids and plasma exchange treatment, but died of progressive pulmonary hemorrhage and multiple cerebral hemorrhage. Silicone implantation is associated with scleroderma, systemic lupus erythematosus, and rheumatoid arthritis. This case report indicates the possibility of the development of MPA after silicone breast implantation.

A critical role for sialylation in cryoglobulin activity of murine IgG3 monoclonal antibodies.

Cryoprecipitating IgG3 autoantibodies have been shown to play a significant role in the development of murine lupus-like autoimmune syndrome. However, the structural basis of IgG3 cryoprecipitation still remains to be defined. In view of the implication of positively charged amino acid residues present in variable regions in IgG3 cryoglobulin activity, we explored the role of terminal sialic acids in oligosaccharide side chains for the cryogenic activity of IgG3 mAb. Comparative oligosaccharide structural analysis of different cryogenic and non-cryogenic IgG3 mAb showed an inverse correlation between the extent of sialylation and cryogenic activity. The inhibitory role of sialylation was further confirmed by the demonstration of enrichment of less and more sialylated IgG3 in cryoprecipitated and noncryoprecipitated fractions, respectively, separated from four different cryogenic IgG3 mAb. Significantly, the sialic acid contents of the latter fraction became comparable to those of non-cryogenic IgG3 mAb. Finally, we observed that highly sialylated non-cryogenic IgG3 mAb was more potent in the inhibition of cryoprecipitation of cryogenic IgG3 mAb. Our results thus suggest that the content of negatively charged sialic acids in oligosaccharide side chains is one of the critical factors to determine IgG3 cryoglobulin activity, along with amino acid sequences of the IgG3 variable regions.

Th2 cytokines increase and stimulate B cells to produce IgG4 in idiopathic membranous nephropathy.

BACKGROUND: The predominant deposition of IgG4 in idiopathic membranous nephropathy indicates that its presence characterizes the systemic immune response of the disease. METHODS: We analyzed the expressions of CD3, CD19, CD4, and CD8 on peripheral blood mononuclear cells (PBMCs) by flow cytometry, and the levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), interferon (IFN)-gamma, interleukin (IL)-4, IL-10, and IL-13 mRNAs in PBMCs using real-time reverse transcription-polymerase chain reaction (RT-PCR) in 14 patients with idiopathic membranous nephropathy and 14 normal control donors. The levels of IgG subclasses in the B-cell culture supernatant in the presence or absence of cytokines were quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS: Idiopathic membranous nephropathy patients showed an increased CD4(+)/CD8(+) ratio, although the numbers of peripheral T and B cells were comparable to those of the normal control group. IL-10 and IL-13 mRNA expression levels increased in the idiopathic membranous nephropathy group. The levels of spontaneous production of each IgG subclass by B cells were identical in the two groups. In the presence of Th2 cytokines, B cells from several individuals of the idiopathic membranous nephropathy group augmented the production of IgG4. When the individual levels of each IgG subclass in the presence of cytokines were compared with those in the absence of cytokines in each sample, a significant increase in the production of IgG4 in the presence of IL-4 was observed in the idiopathic membranous nephropathy group. CONCLUSION: These results indicate that the altered functions of T cells to produce Th2 cytokines and the increased production of IgG4 by B cells in response to these cytokines characterize the immune response in idiopathic membranous nephropathy.