Reducing immunosuppression preserves allograft function in presumptive and definitive polyomavirus-associated nephropathy.
Early detection of polyomavirus BK (BKV) viremia and reduction of immunosuppression is recommended for preventing polyomavirus-associated nephropathy (PyVAN), but systematic histological evaluations were not performed in previous studies. We routinely screen for decoy cells and, if positive, measure plasma BKV-loads. In a cohort of 203 consecutive renal transplantations performed from 2005-2008, 38 patients (19%) developed BKV-viremia and were treated with reduction of immunosuppression. Based on subsequent allograft biopsy results and peak BKV-viremia, patients were assigned to three groups: (i) definitive PyVAN (n = 13), (ii) presumptive PyVAN defined by plasma BKV-loads of ≥ 4 log(10) copies/ml (n = 17) and (iii) low BKV-viremia (n = 8). Clearance of BKV-viremia was achieved in 35/38 patients (92%) and subsequent clinical rejection occurred in 3/35 patients (8.6%), both without any difference among the groups. Patients with definitive PyVAN had higher peak plasma BKV-loads and required longer time for clearance (8.8 vs. 4.6 vs. 2.9 months; p = 0.001). However, allograft function remained stable from baseline to last follow-up at 34 months (range 18-60) in all three groups with median serum creatinine of 1.6 mg/dl, 1.6 mg/dl and 1.3 mg/dl, respectively. We conclude that screening for BKV-replication and reduction of immunosuppression is an effective strategy to preserve medium-term allograft function even in patients developing definitive PyVAN.
Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Switzerland. schaubs@uhbs.ch
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S
Schaub
H H
HH
Hirsch
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M
Dickenmann
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J
Steiger
M J
MJ
Mihatsch
H
H
Hopfer
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M
Mayr
D000328:Adult; D000368:Aged; D001739:BK Virus / Q000235:genetics / Q000302:isolation & purification*; D003404:Creatinine; D005260:Female; D006084:Graft Rejection; D006801:Humans; D007165:Immunosuppression Therapy; D007674:Kidney Diseases / Q000821:virology*; D016030:Kidney Transplantation / Q000473:pathology; D008297:Male; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000821:virology*; D014412:Tumor Virus Infections / Q000821:virology*; D014766:Viremia / Q000821:virology*
D003404:Creatinine