Prospective monitoring of BK polyomavirus infection early posttransplantation in nonrenal solid organ transplant recipients

Background. BK virus-associated nephropathy is an important cause of renal dysfunction in renal transplant recipients. Renal dysfunction after nonrenal solid organ transplantation (NRSOT) is common; however, the impact of BK virus remains uncertain. Methods. Sixty (7 heart, 25 liver, and 28 lung) NRSOT recipients were enrolled in this single center prospective longitudinal study. Urine and plasma were collected for detection of BK viral load using a real-time quantitative polymerase chain reaction assay at transplantation and at 3, 6, and 9 months posttransplantation. Demographic and clinical data including serum creatinine and immunosuppressive therapy were also collected. Results. BK viruria was detected in 16 of 193 (8.3%) samples corresponding to 9 of 60 (15%) subjects. The median BK viral load was 1.12 x 10(-5) (range, 1.1 x 10(2) -2.66 x 10(8)) copies per milliliter. No viremia was detected. In seven of nine, viruria occurred by 3 months posttransplantation. At 9 months of posttransplantation, the median Modification of Diet in Renal Disease-estimated glomerular filtration rate in those with BK viruria on at least one sample was similar to those without viruria (58.0 [IQR 43.1-60.7] mL/min/1.73 m(2) vs. 61.4 [IQR 50.6-74.4] mL/min/1.73 m(2); P = 0.39). Conclusions. Although BK infection was common in this NRSOT population, BK viremia was not observed and there was no association between BK viruria and renal dysfunction. Our data suggest that routine surveillance for BK virus early posttransplantation in NRSOT may not be warranted but should be further examined in a larger multicenter trial.