Periodic assessment of urine and serum by cytology and molecular biology as a diagnostic tool for BK virus nephropathy in renal transplant patients.
OBJECTIVE
To investigate the significance of polyomavirus (PV) viruria and viremia by morphologic, immunohistochemical and molecular analysis (multiplex nested-polymerase chain reaction) in renal transplant patients.


METHODS
Urine (n=328), serum (n= 53) and renal biopsies (n=24) from renal transplant patients (n=106) were studied.


RESULTS
Decoy cells were found in 53 samples (16%) from 19 patients (18%); viral DNA was amplified in all urinary samples and disclosed BK virus (BKV) (n=24), JC virus (JCV) (n=16), and JCV and BKV DNA (n=13). BKV was the prevailing genotype in patients with a high frequency of decoy cell excretion (p = 0.001). JCV excretion correlated with a low number (p = 0.01) and BKV with a high number of decoy cells (p=0.003). PV DNA was amplified from 30/53 serum samples (56.6%); BKV was the prevailing genotype (p = 0.04). On 24 renal biopsies (18 from the decoy cell-negative and 6 from the decoy cell-positive group) PV nephropathy (PVN) was identified and BKV DNA amplified in 4 biopsies, all from the group with a high frequency of decoy cell excretion. PVN was not identified in renal biopsies from the decoy cell-negative group.


CONCLUSIONS
PV infection is frequent in renal transplant patients. The BKV genotype in urine and serum is significantly related to a high frequency and high number of decoy cells. PVN occurs only in patients with BKV viremia and a high number and frequency of decoy cell excretion in urine. In the absence of decoy cells, PVN can be excluded. Cytologic analysis of urine is an important diagnostic tool for screening renal transplant patients at risk of PVN.
Boldorini
Renzo
R
Department of Medical Sciences, Faculty of Medicine and Surgery, Amedeo Avogdro University of East Piedmont, and Unit of Nephrology, Dialysis and Transplantation, Maggiore Hospital, Novara, Italy. renzo.boldorini@med.unipmn.it
Brustia
Maddalena
M
Veggiani
Claudia
C
Barco
Diaa
D
Andorno
Silvano
S
Monga
Guido
G
D000328:Adult; D000368:Aged; D001739:BK Virus / Q000235:genetics / Q000302:isolation & purification*; D003581:Cytodiagnosis; D004279:DNA, Viral / Q000097:blood / Q000652:urine; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis* / Q000473:pathology / Q000821:virology; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000175:diagnosis* / Q000473:pathology; D011183:Postoperative Complications; D014412:Tumor Virus Infections / Q000175:diagnosis* / Q000473:pathology; D014556:Urine / Q000166:cytology* / Q000821:virology; D014766:Viremia / Q000175:diagnosis* / Q000473:pathology
D004279:DNA, Viral