Background: BK polyomavirus (BKPyV) is the most important polyomavirus affecting renal transplant recipients. BKPyV associated nephropathy (BKVAN) is seen in about 5% of renal transplant patients and can lead to graft loss in up to 50% of cases. Monitoring of specific immunity combined with viral load could be used to individually assess the risk of viral reactivation. However, cellular immunity and targeting the immune system have also the potential to be used in therapy development. Consequently, we performed a rapid review about cellular immune responses to summarize the evidence for planning new research on treatment. Additionally, we present an immunologically interesting case of BKVAN. Methods: We performed a rapid review with a search in MEDLINE from 1971 to 2021. Additionally, we present an immunological interesting case of BKVAN. Results: The literature search for original studies yielded 92 results. Finally, nine studies were considered, two of them were experimental studies, three retrospective case series and four prospective clinical trials. On the whole, there is evidence that virus-specific T cells could be used for monitoring of BKVAN, but also for therapy. Conclusions: Cellular immune response to BKVAN is complex, but further prospective clinical studies, especially in virus-specific T cells are necessary.