Very Early Severe Posttransplant Recurrent Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis after Kidney Transplantation: Two Case Reports.

Successful kidney transplantation (KTx) in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV) has been reported with excellent patient and graft survival rates. The recurrence of AAV in transplant recipients is rare, and its mechanisms of action are not clearly known. The optimum time for KTx and the relevance of ANCA titer at the time of transplantation remain controversial. We report two cases of extremely rapid recurrent AAV after renal transplantation; both were still ANCA-positive at the time of transplantation, which led us to question the pathogenesis of ANCA antibodies in recurrence in a kidney allograft. Apheresis plus immunosuppressive therapies were ineffective in the first case and the patient became dialysis-dependent, whereas in the second case methylprednisone pulses plus rituximab infusions resulted in long-lasting remission.

Tocilizumab in the Treatment of Chronic Antibody-Mediated Rejection Post Kidney Transplantation: Clinical and Histological Monitoring.

Introduction: Chronic antibody-mediated rejection (cAMR) has very few effective therapeutic options. Interleukin-6 is an attractive target because it is involved in inflammation and humoral immunity. Therefore, the use of tocilizumab (anti-IL6 receptor, TCZ) is a potential valuable therapeutic option to treat cABMR in kidney-transplant (KT) recipients. Materials and Methods: This single-center retrospective study included all KT recipients that received monthly TCZ infusions in the setting of cABMR, between August 2018 and July 2021. We assessed 12-month renal function and KT histology during follow-up. Results: Forty patients were included. At 12-months, eGFR was not significantly different, 41.6 ± 17 vs. 43 ± 17 mL/min/1.73 m2 (p = 0.102) in patients with functional graft. Six patients (15%) lost their graft: their condition was clinically more severe at the time of first TCZ infusion. Histological follow-up showed no statistical difference in the scores of glomerulitis, peritubular capillaritis, and interstitial fibrosis/tubular atrophy (IFTA). Chronic glomerulopathy score however, increased significantly over time; conversely arteritis and inflammation in IFTA ares improved in follow-up biopsies. Conclusion: In our study, the addition of TCZ prevented clinical and histological worsening of cABMR in KT recipients, except for more severely ill patients. Randomized studies are needed to clarify the risk/benefit of TCZ in cABMR.

Efficacy of Plasmapheresis in Nivolumab-Associated ANCA Glomerulonephritis: A Case Report and Pathophysiology Discussion.

Immune checkpoint inhibitors (ICIs) have revolutionized solid organ and hematologic cancer treatments by improving overall prognoses. However, they can lead to overactivation of the immune system and several immune-related adverse events and sometimes affecting the renal system. Although acute interstitial nephritis is well described, we know little about ICI-associated glomerular injury. Herein, we report an exceptional case of renal ANCA positive-associated vasculitis (AAV) after nivolumab therapy. Three weeks after the last nivolumab injection, the patient presented with proteinuria at 1.73 g/g of creatininuria, hematuria, and acute kidney injury needing dialysis associated with lung hemorrhage; anti-neutrophil cytoplasmic antibody (ANCA titer ≥1,280 with myeloperoxidase specificity of 780 U/mL) was positive, and kidney biopsy confirmed glomerular injury with crescents. The patient underwent treatment with steroid pulses, rituximab, and plasmapheresis, resulting in an improvement of the renal function and lung hemorrhage and produced a negative ANCA titer. Despite the results of the PEXIVAS study and the absence of clear benefit of plasmapheresis demonstrated in idiopathic AAV, we suggest that drug-induced AAV may be effectively treated by plasmapheresis, steroids, and rituximab.