Post-transplant immunoglobulin A deposition and nephropathy in allografts

Recurrent Glomerulonephritis after Renal Transplantation: The Clinical Problem

Glomerulonephritis (GN) continues to be one of the main causes of end-stage kidney disease (ESKD) with an incidence rating from 10.5% to 38.2%. Therefore, recurrent GN, previously considered to be a minor contributor to graft loss, is the third most common cause of graft failure 10 years after renal transplantation. However, the incidence, pathogenesis, and natural course of recurrences are still not completely understood. This review focuses on the most frequent diseases that recur after renal transplantation, analyzing rate of recurrence, epidemiology and risk factors, pathogenesis and bimolecular mechanisms, clinical presentation, diagnosis, and therapy, taking into consideration the limited data available in the literature. First of all, the risk for recurrence depends on the type of glomerulonephritis. For example, recipient patients with anti-glomerular basement membrane (GBM) disease present recurrence rarely, but often exhibit rapid graft loss. On the other hand, recipient patients with C3 glomerulonephritis present recurrence in more than 50% of cases, although the disease is generally slowly progressive. It should not be forgotten that every condition that can lead to chronic graft dysfunction should be considered in the differential diagnosis of recurrence. Therefore, a complete workup of renal biopsy, including light, immunofluorescence and electron microscopy study, is essential to provide the diagnosis, excluding alternative diagnosis that may require different treatment. We will examine in detail the biomolecular mechanisms of both native and transplanted kidney diseases, monitoring the risk of recurrence and optimizing the available treatment options.

The Role of IgA in the Pathogenesis of IgA Nephropathy

Immunoglobulin A (IgA) is the most abundant antibody isotype produced in humans, predominantly present in the mucosal areas where its main functions are the neutralization of toxins, prevention of microbial invasion across the mucosal epithelial barrier, and simultaneous maintenance of a physiologically indispensable symbiotic relationship with commensal bacteria. The process of IgA biosynthesis, interaction with receptors, and clearance can be disrupted in certain pathologies, like IgA nephropathy, which is the most common form of glomerulonephritis worldwide. This review summarizes the latest findings in the complex characteristics of the molecular structure and biological functions of IgA antibodies, offering an in-depth overview of recent advances in the understanding of biochemical, immunologic, and genetic factors important in the pathogenesis of IgA nephropathy.