BÖBREK NAKİL HASTALARINDA BK VİRÜS ENFEKSİYONU SONRASI İMMÜNSUPRESİF TEDAVİNİN RETROSPEKTİF DEĞERLENDİRİLMESİ

Abstract

Ercan F., Retrospective Evaluation of Immunosuppressive Therapy After BK Virus Infection in Kidney Transplant Patients; Hacettepe University Faculty of Medicine (HUFM) Department of Internal Medicine Residency Thesis; Ankara, 2024. Reduction of immunosuppression is the main treatment for BK virus (BKV) infection and BKV nephropathy (BKVN), and there are different recommendations in the literature on how to do this. However, there is almost no large study or guideline recommendation on how to continue immunosuppression after BKV remission is achieved. The aim of our study was to investigate the effect of immunosuppressive treatment approaches after BKV remission in kidney transplant recipients and to investigate the effect of increasing immunosuppression on allograft functions and BKV relapse. In our study included 318 kidney transplant patients with BKV infection, followed in the Nephrology outpatient clinic. We assessed demographic data, primary renal diagnosis, pre-transplant dialysis history, induction therapies, donor type, rejection history, BKV PCR titres, creatinine, GFR, and proteinuria using a Complex Linear Model. Patients were divided into two groups: those with initial allograft dysfunction and those without. We analyzed risk factors for BKV infection and its severity using correlation, univariate, and multivariate regression analyses. When the patients who received triple therapy (Calcineurin inhibitor (CNI) + Mycophenolate mofetil (MMF) + Corticosteroid (C/S)) during BKV infection were analysed, the survival of the grafts monitored with dual therapy after discontinuation of MMF was higher than those who were added mTOR inhibitor (mTORi). When patients were compared according to their regimens at the time of remission after BKV remission, it was observed that increasing the dose of any immunosuppressive drug improved both renal function and rejection-free survival in those receiving triple therapy (p=0.033). In patients followed up with dual (CNI + C/S) therapy or mTORi + CNI + C/S, adding MMF or increasing the dose of CNI provided better graft function than not increasing immunosuppression. In addition, the addition of mTORi was not effective in protecting against rejection in the long term in these patients, whereas no rejection developed in patients in whom MMF was added and CNI dose was increased. Three times more rejection was detected in those in whom immunosuppression was not increased (p=0.013). When immunosuppression strategies were compared in terms of their effects on BK relapse after remission, the rates were close to each other and BKVN-related graft loss was not detected in any of the patients. In conclusion, in the immunosuppressive treatment approach after BKV remission, the addition of MMF was evaluated as a more appropriate strategy in terms of rejection risk and renal functions compared to other alternatives. Increasing immunosuppression after BKV remission according to the individual characteristics and immunological risk profiles of patients may reduce the risk of rejection and improve graft survival. Keywords: Kidney transplantation, BK poliomavirus, graft survival, immunosuppressive regimens, remission, rejection.