Risk Factors for BK Viruria, Viremia, and Nephropathy After Living Renal Transplantation.

Abstract

Introduction: From 2008 to 2013, 214 live donor-recipient pairs were investigated before and after renal transplantation (tx) for risk factors for BK viral (BKV) infection (viruria, viremia) and nephropathy (BKVN). Methods: Urine and blood of donors and recipients were tested by quant. PCR (Cepheid-Affigene Kit) before and of recipients after tx (every 3 mos in all and monthly in viremic patients). Recipients with BKV infection and nephropathy were compared with those without in order to find risk factors. In donors and recipients with pre-tx viral replication, VP1 typing of the BKV subtypes was done and compared with that of post-tx infected recipients. Results: 85 of 214 recipients (40%) had post-tx BKV infection: 10% viruria alone, 29% viruria/viremia, and 10% additionally BKVN. Presumed risk factors were compared between post-tx infected (n=85) and non-infected (n=129) recipients: pre-tx viral replication in urine and/or blood of donor and/or recipient, 48 vs 19% (OR 4.1, p<0.0001); ATG-induction, 7 vs 9% (OR 0.7, ns); ABO incompatible tx, 20 vs 25% (OR 0.8, ns); preceding rejection, 28 vs 23%, (OR 1.3, ns); prior renal tx or PRA>20%, 11 vs 8% (OR 1.4, ns); prior other organ tx, 11 vs 8% (OR 2.3, ns); HLA mismatches >3, 45 vs 42% (OR 1.02, ns); donor age >50 yrs, 64 vs 57% (OR 1.3, ns); recipient age >40 yrs, 60 vs 60% (OR 1.0, ns); preceding dialysis >12 mos, 51 vs 47% (OR 1.2, ns). A multivariable logistic regression revealed that only pre-tx viral replication of donor and/or recipient was a factor separating the groups (OR 4.1, p<0.0001). Among recipients with BKVN (n=22), urine and blood became earlier BKV pos. than in patients with viruria/viremia (n=63) (urine, median 49 vs 75 days, p<0.0001; blood, 57 vs 180 days, p<0.0001). In 27 donor-recipient pairs a comparison of the BKV subtypes of pre-tx replicating donor and/or recipient and post-tx infected recipient was possible and made in 24 of 27 pairs the infection by the donor probable. Conclusion: Among 11 tested presumed risk factors for BKV-infection, pre-tx viral replication was the most important one. In recipients with BKVN, time for positivity of urine and blood was significantly shorter than in recipients with viruria/viremia. BKV-transmission by the donor is an important way of post-tx infection of the recipient.