BK-VIRUS NEPHROPATHY IN THE RENAL ALLOGRAFT:  URINE CYTOLOGY, HISTOLOGY, URINE PCR, IMMUNOHISTOCHEMISTRY AND ELECTRON MICROSCOPIC FINDINGS.

 

Kk Park1, HC Kim2, JG Lee3, YC Chang2, and YN Kang1.

 

1 Department of Pathology, Keimyung University School of Medicine, Daegu, Korea

2 Kidney Institute

 

Background:

BK-virus nephropathy is a new complication that increasingly affects renal allografts and causes dysfunction.  The diagnosis can only be made histologically.  The virus affects tubular epithelial cells that show characteristic intranuclear inclusion bodies.  The major reason for impaired graft function and possible way for viral particles to gain access to the blood via peritubular capillaries is necrosis of infected epithelial cells.  BK-virus DNA in the plasma, which can be detected by PCR, is closely associated with nephropathy.  Patients at risk for nephropathy due to infection with the BK-virus are identified by the presence of cells containing viral inclusion bodies (decoy cells) in the urine or by biopsy of allograft tissue.  Asymptomatic BK-virus infection documented by urine cytology or serology is well known, but the clinical course of biopsy-proven interstitial nephritis is not well defined.

 

Patients and Methods:

We have recently experienced five cases of BK-virus nephropathy in the renal allograft biopsies, which were identified by urine cytology, histology, urine PCR, immunostaining and electron microscopy.

 

Results:

We performed immunohistochemistry and electron microscopy for BK-virus in tissue samples from two renal-allograft recipients.  Both of them had decoy cells in the urine cytology.

 

Conclusions:

It is concluded that a manifest renal allograft infection with BK-virus can persist in heavily immunosuppressed patients with recurrent rejection episodes.  BK-virus mainly affects tubular cells and causes necrosis, a major reason for functional deterioration.  A biopsy is required for diagnosis.  Urine cytology can serve as an adjunct diagnostic tool.  BK-virus tubulo-interstitial nephritis-associated graft dysfunction usually calls for judicious decrease in immunosuppression and monitoring for acute rejection.

 

 

 

 

BK-VIRUS NEPHROPATHY IN THE RENAL ALLOGRAFT:  URINE CYTOLOGY, HISTOLOGY, URINE PCR, IMMUNOHISTOCHEMISTRY AND ELECTRON MICROSCOPIC FINDINGS.

 

Kk Park1, HC Kim2, JG Lee3, YC Chang2, and YN Kang1.

 

1 Department of Pathology, Keimyung University School of Medicine, Daegu, Korea

2 Kidney Institute

 

 

Contact Information:

 

Kwan-kyu Park, MD

 

Department of Pathology

Keimyung University School of Medicine

190 Dong-san-dong, Jung-gu, Daegu, Korea

 

Phone:  82-53-250-7465

Fax:  82-53-250-7095

Email:  park1234@dsmc.or.kr