Incidence of polyomavirus-nephropathy in renal allografts: influence of modern immunosuppressive drugs.
BACKGROUND
In recent years an increasing number of cases with polyomavirus (PV)-nephropathy after renal transplantation were reported from several transplant centres. New, highly potent immunosuppressive drugs like tacrolimus or mycophenolate mofetil were accused as risk factors for this increase. However, data about the incidence of PV-nephropathy in correlation to different immunosuppressive therapy concepts are lacking.


METHODS
All renal transplant biopsies performed at Hannover Medical School between 1999 and 2001 (n=1276) were immunohistochemically screened for the presence of PV-specific proteins. The results were correlated to the different immunosuppressive therapy protocols and patients with PV-nephropathy were compared with a matched control group.


RESULTS
PV-nephropathy was found in <1% of all investigated allograft biopsies (11/1276) and in approximately 1% of all patients (7/638), respectively. All patients being immunohistochemically positive for PV-specific proteins also showed the typical morphological changes of PV-nephropathy. Four out of seven patients with PV-nephropathy were under triple immunosuppression comprising tacrolimus and mycophenolate mofetil. Under this immunosuppressive therapy protocol an eight times higher incidence and a 13 times higher risk (multivariate odds ratio 12.7) of PV-nephropathy was observed in our patients compared with the control group.


CONCLUSIONS
PV-nephropathy is a rare but serious complication after renal transplantation. A small group of patients under intensive immunosuppression comprising tacrolimus in combination with mycophenolate mofetil has a significantly increased risk of acquiring this deleterious complication.
Mengel
Michael
M
Institut für Pathologie der Medizinischen Hochschule Hannover, Hannover, Germany. mengel.michael@mh-hannover.de
Marwedel
Magali
M
Radermacher
Jörg
J
Eden
Gabriele
G
Schwarz
Anke
A
Haller
Hermann
H
Kreipe
Hans
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004359:Drug Therapy, Combination; D005260:Female; D006084:Graft Rejection / Q000473:pathology / Q000517:prevention & control / Q000821:virology*; D006085:Graft Survival; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D007676:Kidney Failure, Chronic / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000009:adverse effects* / Q000031:analogs & derivatives / Q000627:therapeutic use; D011120:Polyomavirus; D027601:Polyomavirus Infections / Q000209:etiology*; D011446:Prospective Studies; D012307:Risk Factors; D016559:Tacrolimus / Q000009:adverse effects* / Q000627:therapeutic use; D014412:Tumor Virus Infections / Q000209:etiology*
D007166:Immunosuppressive Agents; D009173:Mycophenolic Acid; D016559:Tacrolimus