Prevention and treatment of atypical haemolytic uremic syndrome after kidney transplantation

Leflunomide in the treatment of BK polyomavirus associated nephropathy in kidney transplanted patients - A systematic review

BK polyomavirus (BKPyV) associated nephropathy (BKVAN) is seen in about 5% of renal transplant patients and can lead to chronic graft failure or graft loss. No effective therapy is available. Leflunomide has shown promising results in BKVAN. We performed a systematic review about the use of leflunomide for the treatment of BKVAN. The recommendations of the Cochrane Handbook of systematic Reviews were followed. Due to different study designs and endpoints no meta-analysis was performed. The literature search for primary studies yielded 274 results. Finally, twelve studies were included with a total of 267 patients. Clearance of BKPyV viremia was reported in 33.3% to 92.3% of cases and 27 graft losses (10.1%). The included studies were very heterogeneous, especially in terms of leflunomide dosing. Pharmacokinetics seem to have an important impact on the efficacy of leflunomide in BKVAN. There was no correlation between leflunomide serum levels and virus reduction. New adverse events of leflunomide have been described, e.g. haemolytic anaemia and thrombotic microangiopathy. Overall, the risk of bias in the studies was assessed as high and the quality of evidence was rated low. The role of leflunomide in BKVAN remains unclear, but further studies seem reasonable and should address pharmacokinetic aspects.

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.

De Novo Atypical Haemolytic Uremic Syndrome after Kidney Transplantation

De novo thrombotic microangiopathy (TMA) can occur after kidney transplantation. An abnormality of the alternative pathway of complement must be suspected and searched for, even in presence of a secondary cause. We report the case of a 23-year-old female patient who was transplanted with a kidney from her mother for end-stage renal disease secondary to Hinman syndrome. Early after transplantation, she presented with 2 episodes of severe pyelonephritis, associated with acute kidney dysfunction and biological and histological features of TMA. Investigations of the alternative pathway of the complement system revealed atypical haemolytic uremic syndrome secondary to complement factor I mutation, associated with mutations in CD46 and complement factor H related protein genes. Plasma exchanges followed by eculizumab injections allowed improvement of kidney function without, however, normalization of creatinine.

Complement Dysregulation and Disease: Insights from Contemporary Genetics

The vertebrate complement system consists of sequentially interacting proteins that provide for a rapid and powerful host defense. Nearly 60 proteins comprise three activation pathways (classical, alternative, and lectin) and a terminal cytolytic pathway common to all. Attesting to its potency, nearly half of the system's components are engaged in its regulation. An emerging theme over the past decade is that variations in these inhibitors predispose to two scourges of modern humans. One, occurring most often in childhood, is a rare but deadly thrombomicroangiopathy called atypical hemolytic uremic syndrome. The other, age-related macular degeneration, is the most common form of blindness in the elderly. Their seemingly unrelated clinical presentations and pathologies share the common theme of overactivity of the complement system's alternative pathway. This review summarizes insights gained from contemporary genetics for understanding how dysregulation of this powerful innate immune system leads to these human diseases.