Polyoma BK virus (BKV)-associated nephropathy (PVAN) is a relevant cause of poor renal allograft survival.In a prospective analysis, we monitored BKV DNA in blood and urine samples from 62 consecutive pediatric kidney recipients. In patients with BKV replication, we analyzed the impact of reduction of maintenance immunosuppression on viral load kinetics and PVAN in patients with BKV replication. BKV-specific immunity was concomitantly evaluated on blood samples of viremic patients, by measuring the frequency of BKV-specific interferon-c -producing and cytotoxic T cells, and BKV IgG antibody levels. At a median follow-up of 24 months, BK viruria was observed in 39 of 62 patients, while BK viremia developed in 13 patients (21%). In all viremic patients, immunosuppression reduction resulted in the clearance of viremia, and prevented development of PVAN, without increasing the rate of acute rejection or causing graft dysfunction. As a consequence of immunosuppression adjustment, an expansion of BKV-specific cellular immunity was observed that coincided with viral clearance. We conclude that treating pediatric kidney transplant patients pre-emptively with immunosuppression reduction guided by BKV DNA in blood is safe and effective to prevent onset of PVAN. BKV-specific cellular immunity may be useful to guide this intervention.

Purpose Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV) –related malignancy expressing EBV antigens that are possible targets of cell therapy, including latent membrane protein 2 (LMP2). We conducted a clinical trial of EBV-targeted cell therapy with autologous virus-specific cytotoxic T lymphocytes (CTLs) for NPC refractory to conventional treatments. Patients and Methods Ten patients with EBV-related stage IV NPC in progression after conventional radiotherapy and chemotherapy received intravenously autologous EBV-specific CTLs reactivated and expanded ex vivo from peripheral blood lymphocytes through stimulation with EBV-transformed autologous B-lymphoblastoid cell lines (LCL). Toxicity, specific cellular immune responses, and clinical tumor responses were evaluated. Results EBV-specific CTLs could be generated in all patients and were predominantly CD3+/CD8+ T lymphocytes displaying specific killing of autologous EBV-LCL, autologous NPC cells as well as autologous targets bearing the EBV antigen LMP2. Patients received two to 23 infusions of EBV-specific CTLs that were well tolerated with the exception of grade 1 to 2 inflammatory reactions at the tumor site in two cases. Control of disease progression was obtained in six of 10 patients (two with partial response and four with stable disease). Analysis of interferon-γ–producing cells demonstrated an increased frequency of EBV-specific immunity, with appearance of LMP2-specific responses in four patients, of whom three had clinical benefit. Conclusion Cell therapy with EBV-targeted autologous CTLs is safe, induces LMP-2-specific immunologic responses, and is associated with objective responses and control of disease progression in patients with stage IV NPC resistant to conventional treatments.

Epstein-Barr virus (EBV)-associated posttransplantation lymphoproliferative disorders (PTLDs) are a well-recognized complication of immunosuppression in solid organ transplant recipients. The reported therapeutic approaches are frequently complicated by rejection, toxicity, and other infectious pathologies, and overall mortality in patients with unresponsive PTLD remains high. Thus, low-toxicity treatment options or, preferably, some form of prophylactic/preemptive intervention are warranted to improve PTLD outcome in this setting. We assessed whether transfer of EBV-specific cytotoxic T lymphocytes (CTLs) generated in vitro from the peripheral blood of allograft recipients receiving immunosuppression could increase EBV-specific killing in vivo without augmenting the probability of graft rejection. Autologous EBV-specific CTLs were generated for 23 patients who were identified as being at risk of developing PTLD through the finding of elevated EBV DNA load. Of the 23 patients, 7 received 1 to 5 infusions of EBV-specific CTLs. CTL transfer was well tolerated, and none of the patients showed any evidence of rejection. An increase of the EBV-specific cytotoxicity was observed after infusion, notwithstanding continuation of immunosuppressive therapy. EBV DNA levels had a 1.5-to 3-log decrease in 5 patients, whereas in the other 2 graft recipients CTL transfer had no apparent stable effect on EBV load. Our data suggest that the infusion of autologous EBVspecific CTLs obtained from peripheral blood mononuclear cells recovered at the time of viral reactivation is able to augment virus-specific immune response and to reduce viral load in organ transplant recipients. This approach may, therefore, be safely used as prophylaxis of EBV-related lymphoproliferative disorders in these patients, following a strategy of preemptive therapy guided by EBV DNA levels. (Blood. 2002;99: 2592-2598