33591-BKV inSIGHT™ T Cell Immunity Testing

The BKV inSIGHT™ T-Cell Immunity Panel measures the strength of BK virus (BKV)-specific T-cell immune responses in patients with BK viremia following kidney transplantation. Effective cellular immunity against BKV is an important factor in controlling viral replication and reducing viral load. BK virus is a common post-transplant complication in kidney transplant recipients and is typically managed through reduction of immunosuppressive therapy, which may increase the risk of allograft rejection.

The Second International Consensus Guidelines on the Management of BK Polyomavirus in Kidney Transplantation highlight the importance of BKV-specific immune responses in controlling infection and support the growing role of immune monitoring as a complement to viral load assessment. Emerging evidence suggests that detection of BKV-specific T-cell immunity is associated with subsequent control of BK viremia, supporting a more individualized approach to the management of transplant patients at risk for BK virus-associated complications.

About Test

BK virus, also known as human polyomavirus, is a highly prevalent, double-stranded DNA virus within the Polyomaviridae family. Following primary infection, typically acquired in childhood, BK virus establishes lifelong latency in the urogenital tract and may reactivate, particularly in immunocompromised individuals. Clinically significant BK virus infection most commonly occurs in transplant populations—especially kidney transplant recipients—where it can lead to BK virus–associated nephropathy and graft dysfunction. A frequent post-transplant complication, BK virus reactivation is associated with an increased risk of allograft injury, rejection, and reduced graft survival. Effective immune control of BK virus relies heavily on T cell–mediated responses, including both CD4+ and CD8+ T cells. Monitoring BK virus–specific T cell immunity using intracellular cytokine staining may help identify patients at higher risk for viral reactivation and guide immunosuppression management and therapeutic interventions.

Fresh whole blood is stimulated with overlapping VP1/VP2 peptides. The percentage of CD4 T-cells responding to stimulation is quantified by analyzing dual expression of CD69 and TNFα or TNFα/IL2 in multicolor flow cytometry assay. The non-specific mitogen Staphylococcal enterotoxin B (SEB) is used as a positive control for CD4 T-cells activation. A study of adult kidney transplant recipients with recent (< 2 weeks) onset of BK viremia >1,000 copies/mL demonstrated that CD4 specific T-cell response to BKV VP1/VP2 was a predictor of controlling BKV viremia within 30 days while non-responders were unlikely to control viremia.

This test was developed and its performance characteristics were determined by Eurofins Viracor. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration.

CD4 and CD8 T cells that co-express CD69 and a cytokine in response to stimulation with BKV specific peptides that is 2-fold higher than the background (DMSO-RPMI) in the sample and contains at least 5 cells in the responding population determines a positive BKV specific T cells response.