Crescentic Glomerulonephritis: What’s different in South Asia? – A Single Center Observational Cohort Study
Chronic Kidney Disease (CKD) is defined as either kidney damage or decreased kidney function for ≥ 3 months. The microvascular changes within the kidney during diabetes are the most common cause of CKD, also referred to as diabetic kidney disease (DKD) or diabetic nephropathy. The other common cause that leads to end-stage renal failure is mesangial proliferative glomerulonephritis (mesPGN). It is histologically characterized by the proliferation of mesangial cells (MC). However, a recent study reports that crescentic glomerulonephritis (Cr. GN) is an increasing cause of CKD. Cr. GN is characterized by the presence of extensive glomerular crescents as the principal histologic finding. There are a few studies of crescentic GN from South Asia to support these findings but there is a lack of data on the different types of Cr.GN and their outcomes.
The author Suceena Alexander and colleagues published a research paper under the title “Crescentic Glomerulonephritis: What’s different in South Asia? – A Single Center Observational Cohort Study” in Wellcome Open Research. The summary of these findings is below:
Objective:
To investigate the features of crescentic glomerulonephritis in South Asia’s population which may provide useful insights into the causality and predictors of severe outcomes.
Method:
It is an observational retrospective cohort study that includes outpatient and inpatient services of the Department of Nephrology in Christian Medical College Hospital, Tamil Nadu. The study includes all patients (≥18 years) who undergone native renal biopsy at this center over a period of 10 years and had ≥50% crescents on histology. The available data and complications were reviewed. Patients were classified into chronic kidney disease (CKD) stages during the follow-up visits, as per estimated glomerular filtration rate (eGFR) calculated by CKD-EPI equation.
Findings:
Study reports, type II Cr. GN is the most common type of Cr. GN with high prevalence in the female population. Lupus nephritis is the most common cause of this type of Cr.GN, followed by infection-related GN and IgA nephropathy. Additionally, findings highlight the severity of presentation in type II & type III Cr. GN patients as they were presented with severe renal failure. As compare to type II Cr. GN, serum complement C3 levels were found to be low in type I and type III Cr. GN.
This study observed lower rates of anti-neutrophil cytoplasmic antibodies (ANCA) seropositivity in type III Cr. GN as compare to other studies. It is important to note that ANCA negative vasculitis could be attributed to other antibodies such as anti-endothelial cell antibodies, or to cell-mediated immune mechanisms which result in neutrophilic activation. The study reports important differences between ANCA-associated vasculitis (AAV) and ANCA negative vasculitis groups. Investigators report a higher level of proteinuria in the ANCA-negative vasculitis group and also prevalent chronic lesions on kidney biopsy. On the other hand, a higher prevalence of fibrous/fibro cellular crescents and tuft necrosis was found in the AAV group.
There was nearly 30% prevalence of ANCA positivity in type I Cr. GN with a predominance of anti-myeloperoxidase (anti-MPO) ANCA making them “double positive Cr. GN”. The study reports that these patients had a poor prognosis when presenting with severe disease and initially behaved more like anti-glomerular basement membrane (anti-GBM) disease than vasculitis with low rates of recovery from renal failure or intermediate risk for renal survival.
Almost half of the patients had developed ESKD at the end of the follow-up period in this study.
Limitation:
It is a single-center study and it was retrospective in nature is the only reported limitation of the study. Authors acknowledge further researched to identify pathways of alternate complement activation in type I and III Cr. GN and to explore the pathogenesis and factors responsible for the increased prevalence of ANCA negative vasculitis in an Asian population.
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