Project description:As aging increases, monoclonal gammopathy is becoming more common and monoclonal gammopathy of renal significance (MGRS) is gaining attention due to frequent renal involvement. Within MGRS, proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a special category. The disease was first described in 2004 and the research history on it is relatively short. Compared with other MGRS, the detection rate of circulating clones is lower in patients with PGNMID, which is easy to miss and misdiagnose in clinical work. In this review, the etiology and clinical features of PGNMID are discussed. It is noted that PGNMID is associated not only with MGRS, but also with malignancy, infection and other factors. PGNMID is not a disease exclusive to the elderly-young people can also develop this disease. Due to the low detection rate of circulating clones in most patients, confirmation of the disease needs to be combined with renal pathology, which emphasizes the importance of completing light and heavy chain subtype staining. Treatment options for patients with PGNMID differ by etiology. For MGRS-associated PGNMID, the current treatment is primarily empirical and more research evidence is needed to fill the treatment gap.
Project description:Structural aberrations of O-linked glycans present in the IgA1 hinge region are associated with IgA nephropathy, but their contribution to its pathogenesis remains incompletely understood. In this study, mice implanted with hybridoma secreting 6-19 IgA anti-IgG2a rheumatoid factor, but not 46-42 IgA rheumatoid factor bearing the same IgA allotype, developed mesangial deposits consisting of IgA, IgG2a, and C3. Studies in immunoglobulin- and C3-deficient mice revealed that the development of these glomerular lesions required the formation of IgA-IgG2a immune complexes and subsequent activation of complement. The proportion of polymeric and monomeric forms, the IgG2a-binding affinity, and the serum levels of IgA-IgG2a immune complexes were similar between 6-19 IgA- and 46-42 IgA-injected mice. In contrast, the analysis of oligosaccharide structures revealed highly galactosylated O-linked glycans in the hinge region of 6-19 IgA and poorly O-glycosylated in the hinge region of 46-42 IgA. Furthermore, the structure of N-linked glycans in the CH1 domain was the complex type in 6-19 IgA and the hybrid type in 46-42 IgA. In summary, this study demonstrates the presence of O-linked glycans in the hinge region of mouse IgA and suggests that 6-19 IgA rheumatoid factor-induced GN could serve as an experimental model for IgA nephropathy.
Project description:A 55-year-old man developed rapidly progressive glomerulonephritis and nephrotic syndrome. A kidney biopsy specimen showed diffuse proliferative and crescentic glomerulonephritis with monoclonal IgG1κ, humps, and nephritis-associated plasmin receptor, indicating infection-associated proliferative glomerulonephritis with monoclonal immunoglobulin G deposits (PGNMID). Despite dialysis-dependent renal failure, symptomatic therapy resulted in spontaneous recovery of the renal function, mimicking post-infectious glomerulonephritis (PIGN). A heterozygous complement factor H mutation was detected by comprehensive genetic testing of alternative pathway regulatory genes, which might lead to persistent infection-triggered alternative pathway activation and account for severe glomerulonephritis. Post-infectious PGNMID and PIGN might share common clinical presentations and pathogenesis related to the complement pathway.
Project description:IntroductionImmunomodulatory drugs (IMiDs) plus dexamethasone are effective for plasma cell dyscrasias, but the treatment efficacy of IMiD in proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) has been rarely reported.MethodsWe retrospectively analyzed the clinicopathologic data of 64 patients with PGNMID (steroid, IMiD, and bortezomib and dexamethasone/Rituximab [BD/RTX] groups) from January 1, 2010 to December 31, 2020, at the National Clinical Research Center of Kidney Disease in Nanjing. The prognosis of patients receiving different treatment regimens were compared. Factors potentially affecting renal prognosis and renal response were evaluated.ResultsTwenty-eight, 26 and 10 PGNMID patients were divided into IMiD group, steroid group and BD/RTX group respectively. The rate of serum M protein detection was significantly lower in the steroid group than in the other 2 groups. Renal remission (P = 0.001 and P = 0.03, respectively) rates and renal complete remission (CR) (P = 0.001 and P = 0.01, respectively) rates were significantly higher in the IMiD and BD/RTX groups than in the steroid group at the last follow-up. Multivariate logistic analysis identified that hypertension and high serum creatinine (SCr) levels (>1.24 mg/dl) decreased renal remission, whereas low C3 levels, IMiD and BD/RTX treatments were positively associated with renal remission. Multivariate Cox analysis identified IgG3 in renal tissue and high SCr levels as poor renal prognostic indicators. Severe adverse events were more common in the IMiD and BD/RTX groups than in the steroid group (P = 0.072 and P = 0.035, respectively).ConclusionOur results suggest that IMiDs plus dexamethasone is effective for achieving renal remission in PGNMID patients.
Project description:IntroductionProliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) occasionally presents refractory nephrotic syndrome resulting in poor renal prognosis, but its etiology is not fully elucidated. Given that glomerular endothelial cell (GEC) stress or damage may lead to podocytopathy and subsequent proteinuria, as in thrombotic microangiopathy (TMA), diabetic kidney disease, and focal segmental glomerulosclerosis, we investigated the evidence of glomerular endothelial injury by evaluating the expression of plasmalemmal vesicle-associated protein-1 (PV-1), a component of caveolae in the cases of PGNMID.MethodsWe measured the immunofluorescent PV-1 intensities of 23 PGNMID cases and compared with those of primary membranoproliferative glomerulonephritis (MPGN) (n = 5) and IgA nephropathy (IgAN) (n = 54) cases. PV-1 localization was evaluated with Caveolin-1, and CD31 staining, and the ultrastructural analysis was performed using a low-vacuum scanning electron microscope (LVSEM). To check the association of podocyte injury, we also conducted 8-oxoguanine and Wilms tumor 1 (WT1) double stain. We then evaluated PV-1 expression in other glomerulitis and glomerulopathy such as lupus nephritis and minimal change disease.ResultsThe intensity of glomerular PV-1 expression in PGNMID is significantly higher than that in the other glomerular diseases, although the intensity is not associated with clinical outcomes such as urinary protein levels or renal prognosis. Immunostaining and LVSEM analysis revealed that glomerular PV-1 expression is localized in GECs in PGNMID. 8-oxoguanine accumulation was detected in WT1-positive podocytes but not in PV-1-expressing GECs, suggesting GEC-derived podocyte injury in PGNMID.ConclusionPV-1 overexpression reflects glomerular endothelial injury, which could be associated with podocyte oxidative stress in PGNMID cases.
Project description:Small glomerular IgA deposits have been reported in patients with liver cirrhosis, mainly as an incidental finding in autopsy studies. We recently encountered nine cirrhotic patients who presented with acute proliferative glomerulonephritis with unusually large, exuberant glomerular immune complex deposits, in the absence of systemic lupus erythematosus (SLE) or monoclonal gammopathy-related kidney disease. Deposits were typically IgA dominant/codominant. Our aim was to further elucidate the etiology, diagnostic pitfalls, and clinical outcomes.We present clinical features and kidney biopsy findings of nine cirrhotic patients with an unusual acute immune complex glomerulonephritis. We also identified native kidney biopsies from all patients with liver cirrhosis at our institution over a 13-year period (January 2004 to December 2016) to evaluate presence of glomerular IgA deposits in them (n = 118).Six of nine cirrhotic patients with the large immune deposits had a recent/concurrent acute bacterial infection, prompting a diagnosis of infection-associated glomerulonephritis and treatment with antibiotics. In the remaining three patients, no infection was identified and corticosteroids were initiated. Three of nine patients recovered kidney function (one recovered kidney function after liver transplant); three patients developed chronic kidney disease but remained off dialysis; two patients became dialysis-dependent and one patient developed sepsis and expired shortly after biopsy. Within the total cohort of 118 patients with cirrhosis, 67 others also showed IgA deposits, albeit small; and 42 patients had no IgA deposits.These cases provide support to the theory that liver dysfunction may compromise clearance of circulating immune complexes, enabling deposition in the kidney. At least in a subset of cirrhotic patients, a superimposed bacterial infection may serve as a "second-hit" and lead to acute glomerulonephritis with exuberant immune complex deposits. Therefore, a trial of antibiotics is recommended and caution is advised before immunosuppressive treatment is offered. Unfortunately, most of these patients have advanced liver failure; therefore both diagnosis and management remain a challenge.
Project description:BACKGROUND:Infection-related glomerulonephritis with IgA deposits (IRGN-IgA) is a rare disease but it is increasingly reported in the literature. Data regarding epidemiology and outcome are lacking, especially in Europe. We aimed to assess the clinical, pathologic and outcome data of IRGN-IgA. METHODS:Clinical and outcome data from patients from 11 French centers over the 2007-2017 period were collected retrospectively. We reviewed pathologic patterns and immunofluorescence of renal biopsies and evaluated C4d expression in IRGN-IgA. We analyzed the correlation between histological presentation and outcome. RESULTS:Twenty-seven patients (23 men, mean age: 62?±?15?years) were included. Twenty-one (78%) had Staphylococcus aureus infection and twelve (44%) were diabetic. At the time of biopsy, 95.2% had haematuria, 48.1% had a serum creatinine level of >?4?mg/dL, and 16% had hypocomplementemia. The most common pathologic presentation included mesangial (88.9%) and endocapillary proliferative glomerulonephritis (88.9%) with interstitial fibrosis and tubular atrophy (IF/TA) (85.1%). Diffuse and global glomerular C4d expression was found in 17.8%, mostly in biopsies with acute or subacute patterns, and was associated with a short delay between infection and renal biopsy compared to segmental and focal staining. After median follow-up of 13.2?months, 23.1% died, 46.2% had persistent renal dysfunction and 15.4% reached end-stage renal disease. Renal outcome was correlated to IF/TA severity. CONCLUSIONS:Infection-related glomerulonephritis with IgA deposits is usually associated with Staphylococcus infections and mainly affects adult men. This entity has a poor prognosis which is correlated to interstitial fibrosis and tubular atrophy severity.
Project description:BACKGROUND AND OBJECTIVES: Glomerular deposition of monoclonal Ig has been exceptionally described as the cause of membranoproliferative glomerulonephritis, through activation of the complement alternative pathway (CAP). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We retrospectively studied six adults with monoclonal gammopathy and glomerulonephritis (GN) characterized by isolated C3 deposits. RESULTS: All patients presented with hematuria, associated with chronic renal failure and proteinuria in five patients, three of whom had nephrotic syndrome. Five patients had monoclonal gammopathy of undetermined significance and one had smoldering myeloma. The serum monoclonal IgG (κ four of six, λ two of six) was associated with light chain (LC) proteinuria in five patients. Four patients had low serum C3 and/or factor B levels. C4, factor H (CFH), and I protein levels were normal in five of five patients; none had detectable C3NeF. IgG anti-CFH activity was positive in one case. No mutations in CFH, CFI, and MCP genes were identified in four of four patients. Deposits were intramembranous, subepithelial, and mesangial by electron microscopy, and stained positive for C3 (six of six), properdin, and CFH (two of two) but negative for Ig LC and heavy chains, C4, and C1q (6/6) by immunofluorescence. Five patients progressed to end-stage renal disease over a median period of 47 months, despite chemotherapy in four patients. In one patient, monoclonal λLC deposits were observed on a follow-up kidney biopsy after 4 years. CONCLUSIONS: GN with isolated glomerular C3 deposits might represent an unusual complication of plasma cell dyscrasia, related to complement activation through an autoantibody activity of the monoclonal Ig against a CAP regulator protein.