#1038 Progressive multifocal leukoencephalopathy in kidney transplant recipients: a retrospective multicenter nationwide cohort study

Abstract

Abstract Background and Aims Progressive multifocal leukoencephalopathy (PML) is a serious opportunistic infectious disease affecting the central nervous system caused by JC virus. While extensively studied in patients with HIV infection, haematological malignancies, or undergoing immunotherapies, there is a lack of data concerning kidney transplant recipients (KTRs). Method We performed a retrospective, multicentric, nationwide study. We contacted all kidney transplantation centres in France to gather all cases of PML. We obtained the count of patients with a functional kidney allograft using the registry of the French regulatory agency. Results We collected 24 cases of PML. Between 2012 and 2021, the estimated minimal nationwide incidence of PML was 4.7/100 000 patient-years. The median duration from kidney transplantation to PML was 88 months (interquartile range: 9 to 355). Eight patients (33%) had been exposed to belatacept (median exposure: 18.5 months). Almost all patients underwent reduction or withdrawal of immunosuppressive drug doses and 13 (54%) received a specific treatment. Fifteen patients (65%) died within one year after diagnosis. Conclusion In this nationwide study, PML incidence rate in KTRs was at least 4.7/100 000 patient-years resulting in an alarming 65% mortality rate within a year despite immunosuppressants doses decrease or withdrawal. Further investigations are warranted to demonstrate the efficacy of specific treatments and confirm a potential association between belatacept exposure and PML occurrence, as suggested by our study.