After kidney transplantation (KTx) immunosuppressive therapy causes impaired cellular immune defense resulting in increased risk of polyomavirus-associated nephropathy (PVAN). Prognostic markers for the outcome of Polyoma BK-virus (BKV)-infections are missing. BKV-specific T cells (BKV-Tvis) may serve as a surrogate marker for BKV-associated complications.
After KTx BKV-Tvis were analysed in 20 children with current or previous detection of BKV-DNA in blood at different times over a period of 3.5 years (a maximum of 24 tests per person). Leucocytes were stimulated with BKV-antigens (VP1 and large T). Based on specific cellular activation and induction of intracellular cytokines, BKV-CD4+ and CD8+ Tvis were identified by flow cytometry. BKV-DNA in blood was determined by PCR.
The majority of our study group (16/20) showed -at least temporarily- BKV-CD4+ Tvis (up to 6.7 cells/¯o;l), whereas only 10 patients had BKV-CD8+ Tvis (up to 2.0 cells/¯o;l). Children with biopsy proven florid PVAN (n=4) were characterized by persistency of blood-BKV-DNA (>3 months) combined with lack or very low levels of BKV-CD4+ Tvis (<0.75 cells/¯o;l). In contrast, in case of high levels of BKV-CD4+ Tvis (>0.75 cells/¯o;l) twelve out of thirteen patients did not show persistency of BKV-DNA in blood longer than 3 months, suggesting that sufficient levels of BKV-CD4+ Tvis (>0.75 cells/¯o;l) enable to overcome BKV-infections. After disappearance of BKV-DNA, BKV-CD4+ Tvis were not permanently detectable in some patients. A temporary, significant detection of BKV-CD8+ Tvis (>0.4 cells/¯o;l) was only found in patients without persistent BKV-DNA. After minimization of immunosuppressive therapy BKV-CD4+ Tvis were increasing simultaneously with decrease of BKV-DNA.
In case of BKV-DNA-detection in blood, low levels of BKV-CD4+ Tvis are associated with increased risk of florid PVAN, whereas patients with sufficient BKV-CD4+ Tvis do not develop BKV-associated complications. Serving as prognostic marker for individual BKV-specific immune defence, levels of BKV-CD4+ Tvis may represent the risk of florid PVAN and optimize individual therapeutic interventions.
To cite this abstract in AMA style:Ahlenstiel T, Sester U, Fehrenbach H, Pape L. Polyoma BK-Virus-Specific T Cells as a Surrogate Marker for Polyomavirus-Associated Nephropathy after Pediatric Kidney Transplantation [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/polyoma-bk-virus-specific-t-cells-as-a-surrogate-marker-for-polyomavirus-associated-nephropathy-after-pediatric-kidney-transplantation/. Accessed October 20, 2020.
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