Polyomavirus infection and its impact on renal function and long-term outcomes after lung transplantation

Abstract

Background: Polyomavirus infection causes nephropathy after kidney transplantation but has not been thoroughly investigated in nonrenal organ transplantation.

Methods: Ninety lung transplant recipients were enrolled, and they provided urine samples for over 4.5 years. Samples were analyzed for BK virus (BKV), JC virus (JCV), and simian virus 40 (SV40) by conventional and quantitative real-time polymerase chain reaction.

Results: Fifty-nine (66%) patients had polyomavirus detected at least once, including 38 patients (42%) for BKV, 25 patients (28%) for JCV, and six patients (7%) for SV40. Frequency of virus shedding in serial urine samples by patients positive at least once varied significantly among viruses: JCV, 64%; BKV, 48%; and SV40, 14%. Urinary viral loads for BKV (10 copies/mL) and JCV (10 copies/mL) were higher than for SV40 (10 copies/mL; P=0.001 and 0.0003, respectively). Polyomavirus infection was associated with a pretransplant diagnosis of chronic obstructive pulmonary disease (odds ratio 6.0; P=0.016) but was less common in patients with a history of acute rejection (odds ratio 0.28; P=0.016). SV40 infection was associated with sirolimus-based immunosuppression (P=0.037). Reduced survival was noted for patients with BKV infection (P=0.03). Patients with polyomavirus infection did not have worse renal function than those without infection, but in patients with BKV infection, creatinine clearances were lower at times when viral shedding was detected (P=0.038).

Conclusions: BKV and JCV were commonly detected in the urine of lung transplant recipients; SV40 was found at low frequency. No definite impact of polyomavirus infection on renal function was documented. BKV infection was associated with poorer survival.

Figure 1. Quantitative viral load in urine by virus

The mean viral load for each patient is used in generating the box plots. Patients who shed two viruses are included in both boxes. The numbers of patients in each box are: BKV (n=38), JCV (n=25), and SV40 (n=6). BKV vs. JCV p=0.21 (Mann-Whitney); BKV vs. SV40 p=0.001; JCV vs. SV40 p=0.0003. In each box and whisker plot, the lower and upper edges of the box indicate the 25^th and 75^th percentiles; the horizontal line within the box represents the median; the whiskers indicate either the minimum and maximum values or a distance of 1.5× the interquartile range from the edge of the box (whichever distance is smaller).

Figure 2

Actuarial curves representing overall survival in patients grouped by BKV infection. Log-rank statistics; p=0.03.