A Longitudinal Molecular Surveillance Study of Human Polyomavirus Viremia in Heart, Kidney, Liver, and Pancreas Transplant Patients

Raymund R. Razonable () 2 3 Robert A. Brown 2 3 Atul Humar 1 2 Emma Covington 0 2 Emma Alecock 0 2 Carlos V. Paya 2 3 the PV 2 Study Group 2 4 0 Roche Products, Welwyn Garden City, Herts, United Kingdom 1 University of Toronto , Toronto, Canada 2 Received 1 March 2005; accepted 26 May 2005; electronically published 14 September 2005. Presented in part: American Transplant Congress, Boston, Massachusetts , 14-19 May 2004 (abstract 662). Potential conflicts of interest: R.R.R. has received honoraria for speaking and is an ad hoc consultant to the sponsor; A.H. is a consultant to the sponsor; E.C. and E.A. are employees of the sponsor. Financial support: F. Hoffmann-La Roche 3 Division of Infectious Diseases and Internal Medicine, Mayo Clinic College of Medicine , Rochester, Minnesota 4 Study group members are listed after the text. Internal Medicine, Mayo Clinic College of Medicine , 200 First St. SW, Marian Hall 5, Rochester, MN 55905 - In this study of 263 heart, kidney, liver, and pancreas transplant patients, BK virus (BKV) and JC virus (JCV) DNAemia were observed most commonly in kidney and/or pancreas transplant patients (26%), although they were also observed, to a lesser extent, in heart (7%) and liver (4%) transplant patients. The majority of episodes of polyomavirus DNAemia were subclinical, although, in some cases, BKV DNAemia was associated with kidney rejection, and JCV DNAemia was accompanied by nonspecific symptoms. Hence, BKV and JCV DNAemia are not uncommon during the first year after kidney, heart, liver, and pancreas transplantation, and they could be associated with certain clinical syndromes in transplant patients. Infections with human polyomaviruses BK virus (BKV) and JC virus (JCV) are widespread, with seroprevalence in 90% of adults [1]. After primary infection, these viruses persist in the kidneys, blood, and brainsites that serve as reservoirs for reactivation and as vehicles for transmission to susceptible hosts. Several syndromes are attributed to polyomavirus in transplant patients [2]: BKV causes tubulointerstitial nephritis, ureteral stenosis, and graft dysfunction in kidney transplant patients and hemorrhagic cystitis in hematopoietic stem cell transplant (HSCT) patients, whereas JCV causes progressive multifocal leukoencephalopathy (PML). JCV has also been associated with nephropathy in kidney transplant patients [3]. Beyond these clinical syndromes, the effect of BKV and JCV viremia on transplant outcomes is less clear. Specifically, the incidence and clinical manifestations of BKV viremia in nonkidney solid organ transplant (SOT) patients are undefined. Likewise, the incidence and clinical manifestations of JCV viremia after SOT and its effect on transplant outcomes remain to be investigated. Studies describe an in vitro interaction between polyomaviruses and cytomegalovirus (CMV) [46]: CMV enhances polyomavirus replication [4, 6, 7], and, conversely, polyomaviruses have transactivating properties that enhance CMV replication [5]. However, clinical data that support these interactions in vivo are limited. Organ transplantation, which allows reactivation of viruses, offers a unique environment to study these viral interactions. Hence, we conducted the present study to investigate the epidemiology and clinical relevance of BKV and JCV in a cohort of SOT patients at high risk of CMV disease. Patients and methods. Two hundred sixty-three (72%) of the 364 CMV-seronegative recipients of a heart, kidney, liver, or pancreas from a CMV-seropositive donor (CMV D+/R ) who participated in the PV16000 trial that compared valganciclovir (n p 168) and oral ganciclovir (n p 95) for prevention of CMV disease were studied [8]. All patients received oral ganciclovir or valganciclovir prophylaxis for 100 days. Peripheral blood samples were collected from all patients within 10 days after transplantation (before prophylaxis); on days 14, 42, 70, and 100 (during prophylaxis); and at months 4, 4.5, 6, 8, and 12 after transplantation. The blood samples were stored at 70 C until use in the present study. There were 2232 blood samples collected from the 263 patients (mean, 8.5 samples/patient), all of which were analyzed for BKV and JCV DNAemia at the Mayo Clinic research laboratory (Rochester, MN). Viral DNA was extracted from 200 mL of whole blood (Isoquick; ORCA Research) and was eluted in 25 mL of DNAse-free and RNAse-free water. Five microliters of eluted DNA was added to 15 mL of Mastermix Solution (Roche Molecular Biochemicals) containing primers and probes that amplify the viral capsid protein VP2, as described elsewhere [9]. BKV and JCV DNA were quantified by use of a LightCycler (Roche Molecular Biochemicals). The primer-probe combination detected both viruses, which were differentiated by their peaks in the melting curve analysis [9]. During the PV16000 trial, clinical events during the first year after transplantation were prospectively recorded in a database that was maintained by the sponsor. In the present study, these events were correlated with the presence and degree of polyomavirus replication. The association between polyomavirus DNAemia and CMV disease, serum creatinine and creatinine clearance, allograft rejection, and other clinical symptoms was evaluated. The overall and organ-specific incidences of BKV and JCV DNAemia were calculated on the basis of the total number of patients and for each organ type. Prevalence was calculated on the basis of the total number of patients for each specific time point. Data are presented as proportions, means, and medians. Statistical analysis was performed by use of the x2 test or Fishers exact test, as appropriate, and by use of the Wilcoxon 2-sample test. The level of statistical significance was P ! .05. Results. Thirty-two (12.2%) of 263 CMV D+/R patients developed BKV DNAemia (range, 222,680 copies/mL) at the median time to onset of DNAemia, which was day 100 after transplantation. The prevalence of BKV DNAemia was highest (6.2%) at 4.5 months (figure 1A). Half of the BKV DNAemia episodes were transient (detected at 1 time point). The incidence of BKV DNAemia was similar during and after antiviral prophylaxis, although it was observed more commonly in patients receiving oral ganciclovir prophylaxis (17.9%) than in patients receiving valganciclovir prophylaxis (8.9%) (P p .03). Twenty-four (75%) of the 32 BKV DNAemic patients were kidney transplant patients. Hence, in 92 kidney transplant patients, the first-year incidence of BKV DNAemia was 26% (figure 1B). The majority of BKV DNAemic episodes in kidney transplant patients were subclinical. In 6 patients (25%), incidence of BKV DNAemia coexisted with clinical or biopsy-proven acute graft rejection; 2 of these patients lost their allograft because of persistent poor graft function or recurrent acute rejection. A higher peak BKV load was observed in patients who developed graft rejection (4108 vs. 652 copies/mL) than in those who lost the (...truncated)