Resurgence of BK Virus following Covid-19 in kidney transplant recipients.

Masset, Christophe; Ville, Simon; Halary, Franck; Gaborit, Benjamin; Bressolette-Bodin, Celine; Deltombe, Clément; Dujardin, Amaury; Jacquemont, Lola; Lebot, Sabine; Kervella, Delphine; Figueres, Lucille; Cantarovich, Diego; Giral, Magali; Hourmant, Maryvonne; Blancho, Gilles; Garandeau, Claire; Meurette, Aurélie; Dantal, Jacques

Kidney transplant recipients have been supposed vulnerable to severe Covid-19 infection, due to their comorbidities and immunosuppressive therapies. Mild-term complications of Covid-19 are currently unknown, especially in this population. Herein, we report two cases of BKV replication after non-severe SARS-CoV-2 infection. The first case was a 59-year-old man, transplanted 3 months ago, with recent history of slight BKV viremia (3.3 log10 DNA copies/ml). Despite strong reduction of maintenance immunosuppression (interruption of mycophenolic acid and important decrease of calcineurin inhibitors), BKV replication largely increased after Covid-19 and viremia persisted at 4.5 log copy/ml few months later. The second case was a 53-year-old woman, transplanted 15 years ago. She had recent history of BKV cystitis, which resolved with decrease of MPA dosage. Few weeks after SARS-CoV-2 infection, she presented recurrence of lower urinary tract symptoms. Our reports highlight that SARS-CoV-2 infection, even without severity, could disrupt immune system and particularly lymphocytes, thus leading to viral replication. Monitoring of viral replications after Covid-19 in kidney transplant recipients could permit to confirm these preliminary observations.