Characterization of BK polyomavirus-associated nephropathy (BKPyVAN) in kidney transplant recipients using transcriptomic analysis: a comprehensive scoping review.

BK polyomavirus (BKPyV) infection reactivates with immunosuppressive therapies and can lead to the development of BKPyV-associated nephropathy (BKPyVAN) in kidney transplant recipients. This scoping review assesses the use of transcriptomics to profile BKPyVAN in kidney transplant recipients. The following search strategy was employed in Medline and Embase: 'BK virus' or 'BK polyomavirus' or 'Polyomavirus' AND 'Kidney transplant' or 'Nephritis' or 'Nephropathy' AND 'Gene expression' or 'Transcriptomics' or 'mRNA'. The search identified 368 publications (264 EMBASE and 104 MEDLINE), and after removal of duplicates (92) and abstract/full-text screening, there were 11 eligible studies which included 7 original transcriptomic studies and 4 bioinformatic studies. There was consistent dysregulated expression of proinflammatory pathways (e.g. cytokines, chemokines, T- and B-cell-related pathways) in BKPyVAN compared with stable graft function. There was considerable overlap between the gene expression patterns identified in BKPyVAN and T-cell mediated rejection that require more exploration. This review highlights limitations including small sample sizes, lack of validation, and variation in technical platforms and study designs. Transcriptomics in BKPyVAN is currently underutilized and there is a genuine need for further research in larger cohorts to provide action in discovering novel therapeutic targets and discriminative gene expression signatures to guide individualized therapeutic strategies.