BK virus-associated nephropathy in renal allograft recipients: rescue therapy by sirolimus-based immunosuppression.
BACKGROUND
BK virus nephritis (BKN) in recipients of renal allografts has reemerged during the past 5 years. Despite increased incidence, therapeutic options remain limited and progression of the disease often leads to allograft failure.


METHODS
From May 2002 to July 2002, we performed protocol biopsies in 25 recipients of kidney allografts with progressive allograft dysfunction; three patients demonstrated unexpected histopathologic features of BKN. We tested the hypothesis that replacement of their lymphocytotoxic and nephrotoxic immunosuppression (combination of mycophenolate and tacrolimus) with sirolimus- and prednisone-based therapy can lead to disappearance of the virus without increasing the risk of acute rejection.


RESULTS
During the median follow-up of 18 months after sirolimus and prednisone therapy, decoy cells disappeared first, followed by progressive decrease in the median plasma BK virus-DNA load, and undetectable levels at the last follow-up. Patients remained free of acute rejection, and follow-up median estimated creatinine clearance increased to 67 mL/min (range 62-75 mL/min) from 52 mL/min (range 51-54 mL/min) at the time of diagnosis.


CONCLUSIONS
Further studies are needed, but at present these preliminary results offer a new direction for therapeutic intervention in recipients of renal allografts with BKN.
Division of Nephrology, Department of Internal Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA. rwali@medicine.umaryland.edu
Ravinder K
RK
Wali
Cinthia
C
Drachenberg
Hans H
HH
Hirsch
John
J
Papadimitriou
Anita
A
Nahar
Viresh
V
Mohanlal
Meredith A
MA
Brisco
Stephen T
ST
Bartlett
Matthew R
MR
Weir
Emilio
E
Ramos
D000328:Adult; D001739:BK Virus; D001706:Biopsy; D004279:DNA, Viral / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007674:Kidney Diseases / Q000517:prevention & control*; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000517:prevention & control*; D020123:Sirolimus / Q000009:adverse effects / Q000627:therapeutic use*; D014184:Transplantation, Homologous; D014412:Tumor Virus Infections / Q000517:prevention & control*
D004279:DNA, Viral; D007166:Immunosuppressive Agents; D020123:Sirolimus