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Updated: May 11, 2026
11:54
Measurement of BK-polyomavirus Non-Coding Control Region Driven Transcriptional Activity Via Flow Cytometry
Published on: July 13, 2019
Pathology of resolving polyomavirus-associated nephropathy
Summary
Reducing immunosuppression effectively controls polyomavirus BK (BKV) and resolves BKV-associated nephropathy (PyVAN). Resolving PyVAN shows inflammation similar to interstitial rejection but typically self-limits, preserving allograft function.
Area of Science:
- Nephrology
- Virology
- Immunology
Background:
- Polyomavirus BK (BKV) infection is a significant complication after kidney transplantation.
- BKV-associated nephropathy (PyVAN) management often involves reducing immunosuppression.
- The histological changes during PyVAN resolution are not well-characterized.
Purpose of the Study:
- To systematically investigate the morphology of resolving BKV-associated nephropathy (PyVAN).
- To correlate histological findings with BKV viremia levels and clinical outcomes.
- To assess the impact of immunosuppression reduction on PyVAN resolution and allograft function.
Main Methods:
- Analysis of 99 surveillance biopsies from 35 kidney transplant patients with BKV viremia.
- Biopsies were scored using Banff criteria and grouped by BKV viremia status (pre-, increasing, decreasing, post-).
- Correlation of SV40 immunohistochemistry with plasma BKV load and assessment of inflammatory markers.
Main Results:
- 97% of patients cleared BKV viremia after a median of 9 months.
- Tubulitis and interstitial inflammation scores increased during decreasing viremia and persisted post-clearance.
- Resolving PyVAN showed features of acute interstitial nephritis, sometimes with plasma cell infiltration and HLA-DR expression.
Conclusions:
- Reducing immunosuppression is effective in clearing BKV viremia and resolving PyVAN.
- Resolving PyVAN exhibits histological characteristics that can mimic interstitial rejection.
- The process is typically self-limiting, with stable or improved allograft function and low rates of clinical rejection post-clearance.
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