Routine immunohistochemistry study for polyomavirus BK nephropathy in transplanted kidney biopsies, is it...

Area of Science:

• Nephrology
• Transplantation Immunology
• Virology

Background:

• Polyomavirus BK Nephropathy (PVBKN) poses diagnostic challenges in kidney transplant recipients.
• Current gold standard histopathology may miss early-stage PVBKN, as viral inclusions are not always apparent.
• Immunohistochemistry (IHC) is a potential diagnostic tool, but its routine use lacks consensus.

Purpose of the Study:

• To evaluate the diagnostic utility of immunohistochemistry (IHC) for Simian Virus 40 (SV40) antigen in identifying early Polyomavirus BK Nephropathy (PVBKN).
• To compare the sensitivity and specificity of histopathology with and without IHC in diagnosing PVBKN in transplanted kidneys.

Main Methods:

• Retrospective analysis of 275 transplanted kidney biopsy samples from 2016-2019.
• Samples were evaluated using routine stains and IHC for SV40 antigen.
• PVBKN diagnosis was confirmed by typical viral inclusions or positive IHC staining (≥1+).

Main Results:

• 18 cases (6.5%) of PVBKN were diagnosed.
• Histopathology alone detected typical viral inclusions in 77.7% of PVBKN cases.
• IHC identified an additional 22.2% of PVBKN cases missed by routine histopathology, demonstrating higher sensitivity.

Conclusions:

• Routine IHC for SV40 antigen significantly enhances diagnostic sensitivity for early-stage PVBKN in kidney transplant biopsies.
• Implementing routine IHC can improve the early detection and management of PVBKN.
• This approach aids in timely intervention for patients with new-onset allograft dysfunction.