Do BKPyV genomic features underlie clinical divergence between kidney and hematopoietic transplant recipients?

This study explores whether viral determinants of BK polyomavirus (BKPyV) may contribute to the distinct clinical manifestations observed in kidney transplant recipients (KTR) and hematopoietic stem cell transplant recipients (HSCT). Although BKPyV reactivation is typically attributed to graft type and immunosuppression—resulting mainly in nephropathy in KTR and hemorrhagic cystitis in HSCT—the potential impact of viral genotype or specific SNPs on renal versus bladder tropism remains poorly defined. By analyzing BKPyV genotypes and whole-genome sequences from KTR and HSCT, we assessed whether particular viral lineages or mutational signatures were associated with either graft type or clinical outcomes. While overall genotype distribution was similar across groups, we observed a higher frequency of SNPs within the small t antigen gene among KTRs, suggesting a possible but modest viral contribution that merits further investigation.