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The urgent need for more research on how to treat recurrent focal and segmental glomerulosclerosis

Renal transplantation is the therapy of choice for endstage renal disease (ESRD) in children and adolescents.1 Unfortunately, some diseases recur in the transplant, such as hyperoxaluria type I2 and focal and segmental glomerulosclerosis (FSGS).3 Whereas pursuing a liver transplant and aggressively normalizing plasma oxalate levels prior to transplantation are two key strategies to prevent the loss of a renal transplant from recurrent disease of hyperoxaluria type I,4 strategies for the treatment of recurrent FSGS have been of variable success. Although a large number of therapies have been tried, outcomes of recurrent FSGS remain poor.5 Of the treatments utilized for recurrent FSGS, most are not evidencebased. The only attempt for a metaanalysis for recurrent FSGS is comprised of case reports and case series including 432 patients utilizing plasmapheresis with an overall partial or complete remission rate of 71%.6 Even such a large case series could be subject to a substantial reporting bias, as negative results tend to be published less frequently. While there is some evidence to support plasmapheresis, there are still many uncertainties: For instance, it is unclear whether or not there is a place for preemptive plasmapheresis after transplantation. A recent publication in Pediatric Transplantation demonstrated a low value of prophylactic plasmapheresis for the prevention of recurrence of FSGS.7 Another confounding factor stems from the fact that singlecenter studies will rarely have sufficient numbers for any meaningful conclusions. Registry data are one way to eliminate reporting bias. In one study of the Irish Transplant Registry, 60.5% of patients developed recurrent FSGS in the first transplant, whereas 86% of patients with a recurrence in the first transplant also recurred in the second, and clearly, recurrent FSGS was associated with high rates of graft failure.8 In children, up to 12% of patients with endstage kidney disease may have FSGS according to the Latin American Registry ALANEPE.9 The quality of data about the prevalence of FSGS around the world varies. One large comparative study by Harambat et al10 suggests that glomerulonephritis (FSGS would be listed under that category) ranges from 5% in the Italian registry to 29% in Australia and New Zealand, suggesting that ANZDATA may have the highest prevalence of FSGS patients. The North American registry had 14%, and the European registry had 15%.10 Unfortunately, registry reports rarely focus on one topic. In an old study, Tejani et al11 reported a 20% recurrence rate among 132 pediatric renal transplant recipients with FSGS. We are only aware of one other more recent pediatric study on recurrent FSGS, which had a similar recurrence rate and confirmed a 78% partial or complete response rate with plasma exchange.12 In that context, we are delighted to see the manuscript from Australia and New Zealand in this edition of Pediatric Transplantation which provides a detailed assessment of all patients with recurrent FSGS from 19902015.13