Fatal donor-derived Epstein-Barr virus-associated post-transplant lymphoproliferative disorder following reduced intensity volunteer-unrelated bone marrow transplant for myelodysplastic syndrome

Greatly reduced risk of EBV reactivation in rituximab-experienced recipients of alemtuzumab-conditioned allogeneic HSCT

EBV-associated post-transplant lymphoproliferative disease (PTLD) remains an important complication of allogeneic haematopoietic stem cell transplantation (allo-HSCT). We retrospectively analysed the incidence and risk factors for EBV reactivation in 186 adult patients undergoing consecutive allo-HSCT with alemtuzumab T-cell depletion at a single centre. The cumulative incidence of EBV reactivation was 48% (confidence interval (CI) 41-55%) by 1 year, with an incidence of high-level EBV reactivation of 18% (CI 13-24%); 8 patients were concurrently diagnosed with PTLD. Amongst patients with high-level reactivation 31/38 (82%) developed this within only 2 weeks of first EBV qPCR positivity. In univariate analysis age⩾50 years was associated with significantly increased risk of EBV reactivation (hazard ratio (HR) 1.54, CI 1.02-2.31; P=0.039). Furthermore, a diagnosis of non-Hodgkin lymphoma (NHL) was associated with greatly reduced risk of reactivation (HR 0.10, CI 0.03-0.33; P=0.0001) and this was confirmed in multivariate testing. Importantly, rituximab therapy within 6 months prior to allo-HSCT was also highly predictive for lack of EBV reactivation (HR 0.18, CI 0.07-0.48; P=0.001) although confounding with NHL was apparent. Our data emphasise the risk of PTLD associated with alemtuzumab. Furthermore, we report the clinically important observation that rituximab, administered in the peri-transplant period, may provide effective prophylaxis for PTLD.

Strategies to prevent EBV reactivation and posttransplant lymphoproliferative disorders (PTLD) after allogeneic stem cell transplantation in high-risk patients

Epstein-Barr virus (EBV)-associated postallogeneic stem cell transplantation (SCT) lymphoproliferative disorder (PTLD) is often life threatening. The risk of EBV reactivation is highest in older patients, T cell-depleted SCT (in vivo or vitro), and in unrelated or mismatched SCT. Cumulative numbers of patients with EBV reactivation and PTLD are rising as more patients at high risk for EBV reactivation and PTLD are receiving allo-SCT. Novel but easily applicable strategies are needed to prevent EBV reactivation and PTLD to serve the needs of the increasingly enlarging population of high-risk SCT recipients across the globe.

Incidence and dynamics of Epstein-Barr virus reactivation after alemtuzumab-based conditioning for allogeneic hematopoietic stem-cell transplantation

BACKGROUND

Reactivation of Epstein-Barr virus (EBV) infection and posttransplant lymphoproliferative disorder (PTLD) pose a significant risk after T-cell-depleted (TCD) allogeneic hematopoietic stem-cell transplantation (HSCT). The pattern of EBV reactivation in patients receiving allogeneic HSCT, incorporating in vivo or in vitro alemtuzumab as the method of TCD, is not known.

METHODS

Monitoring for EBV DNA was performed by quantitative polymerase chain reaction on whole blood in 111 consecutive adults undergoing HSCT using alemtuzumab-based TCD. Patients with more than 40,000 copies/mL were screened for PTLD, followed by the withdrawal of immunosuppression and a single infusion of rituximab.

RESULTS

The 2-year cumulative incidence of EBV DNAemia was 40.3%. In vivo alemtuzumab was associated with earlier EBV reactivation than in vitro alemtuzumab (100-day incidence 22.7% vs. 2.8%, P=0.006). Eighteen patients (16%) had EBV DNAemia of more than 40,000 copies/mL. In evaluable patients, the initial rate of increase in EBV DNA levels was significantly faster in those who went on to treatment with rituximab than in patients who were left untreated (mean doubling time 3.5 days vs. 4.2 days, P=0.003). Rituximab treatment induced rapid declines in EBV DNA with an average half-life of 1.2+/-0.7 days. Only one patient (0.9%) had histologic confirmation of PTLD and subsequently attained a complete remission with rituximab that persists at 18 months.

CONCLUSIONS

Alemtuzumab-based TCD is associated with a high frequency of EBV reactivation but a low (<1%) risk of PTLD using a strategy of preemptive rituximab therapy.

Critical Review of Preclinical Approaches to Evaluate the Potential of Immunosuppressive Drugs to Influence Human Neoplasia

Many immunosuppressive drugs are associated with an increased risk of B-cell lymphoma, squamous cell carcinoma, and Kaposi sarcoma. Thirteen immunosuppressive drugs have been tested in 2-year carcinogenicity studies (abatacept; azathioprine; busulfan; cyclophosphamide; cyclosporine; dexamethasone; everolimus; leflunomide; methotrexate; mycophenolate mofetil; prednisone; sirolimus; and tacrolimus) and in additional models including neonatal and genetically modified mice; chemical, viral, ultraviolet, and ionizing radiation co-carcinogenesis, and in models with transplanted tumor cells. The purpose of this review is to outline the mechanisms by which immunosuppressive drugs can influence neoplasia, to summarize the available preclinical data on the 13 drugs, and to critically review the performance of the models. A combination of primary tumor and metastasis assays conducted with transplanted cells may provide the highest value for hazard identification and can be applied on a case-by-case basis. However, for both small molecules and therapeutic proteins, determining the relative risk to patients from preclinical data remains problematic. Classifying immunosuppressive drugs based on their mechanism of action and hazard identification from preclinical studies and a prospective pharmacovigilance program to monitor carcinogenic risk may be a feasible way to manage patient safety during the clinical development program and postmarketing.

EBV-related disease following haematopoietic stem cell transplantation with reduced intensity conditioning

The use of reduced intensity regimens has decreased early mortality following stem cell transplantation. However, the increased immunosuppression following these protocols results in profound and often prolonged lymphopenia, resulting in an increased incidence of viral reactivation. We and others have observed a high incidence of EBV viraemia and post-transplant lymphoproliferative disease (PTLD) following reduced-intensity conditioning regimens, reflecting the delayed recovery of EBV-specific immunity after such transplants. The clinical and histological features at presentation are similar to that seen after conventional intensity conditioning. Given the increasing use of reduced intensity conditioning (RIC) transplants, we review the risk factors for EBV related disease following transplantation with RIC, the potential for pre-emptive therapy of PTLD based on monitoring EBV viraemia and management options in such patients.

Epstein-Barr virus-associated enteritis with multiple ulcers after stem cell transplantation: first histologically confirmed case

The present case involves unique enteritis forming multiple ulcers associated with Epstein-Barr virus (EBV). A 57-year-old man had undergone a reduced intensity allogeneic stem cell transplantation for a relapse of multiple myeloma following sequential autologous peripheral blood stem cell transplantation. The ileum, resected for massive melena, showed multiple irregular ulcers with occasional cobblestone-like appearance. There was inflammation including numerous plasma cells in the ulcer bases and surrounding areas, where many EBV-infected plasma cells were detected by double staining with EBV-encoded small RNA-1 (EBER-1) in situ hybridization and CD79a, while EBV-infected epithelial cells were not noted. The number of EBER-1-positive cells in the ileum (mucosa, 1451 cells/mm(2); submucosa, 465 cells/mm(2)) was much larger than in control samples (malignant lymphoma or leukemia after allogeneic stem cell transplantation, n = 4, range 0-113 cells/mm(2); malignant lymphoma after chemotherapy, n = 14, range 0-0.89 cells/mm(2); colon cancer, n = 12, range 0-3.5 cells/mm(2)). In the mucosa near the ulcers, EBER-1-positive cells often surrounded and involved the glandular epithelium, forming lymphoepithelial-like lesions. The histological findings differ from post-transplant lymphoproliferative disorders or intestinal thrombotic microangiopathy, and this is the first case of EBV-associated enteritis with ulcers characterized by numerous plasma cells and lymphoepithelial-like lesions after stem cell transplantation.

Post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD) is an increasingly recognized complication of solid organ and hematopoietic stem cell transplantation. PTLD represents a spectrum of polyclonal and monoclonal lymphoproliferation, generally of B cells. Prompt diagnosis is key and requires a high index of suspicion. An increasing variety of highly effective therapies, including immune modulation via reduction in immunosuppression, monoclonal antibodies, and cellular therapy, have dramatically improved the cure rates of this once devastating disease.

Increased incidence of EBV-related disease following paediatric stem cell transplantation with reduced-intensity conditioning

The incidence of Epstein-Barr virus (EBV) viraemia and lymphoproliferative disease (LPD) was studied in a consecutive cohort of 128 paediatric patients undergoing stem cell transplantation (SCT) with reduced-intensity conditioning (RIC; n = 65) or conventional-intensity conditioning (CIC; n = 68). Following CIC, six of 68 (8%) developed viraemia; all remained asymptomatic. EBV viraemia (23 of 65 patients = 35%, P < 0.001) and LPD (10 of 65 = 15%, P < 0.001) were significantly more frequent following RIC. Of the 23 RIC patients who developed viraemia, eight remained asymptomatic, five had symptomatic viraemia (fever +/- rash), and 10 patients developed LPD, two of whom died. An absolute lymphocyte count of <0.3 x 10(9)/l at the time of onset of viraemia was strongly predictive of development of LPD (P < 0.05) in this group. The incidence of viraemia was significantly higher in patients receiving serotherapy with antithymocyte globulin (ATG; 15 of 43, 35%) than Campath (12 of 73, 16.4%, P < 0.05). Primary immunodeficiency and acute graft-versus-host disease were associated with EBV viraemia in univariate analysis, but were not independent risk factors. In conclusion, EBV viraemia and LPD appear to be significantly more common in children following RIC SCT, particularly with selective depletion of recipient T cells relative to B cells following the use of ATG. This probably reflects the profound immunosuppression following RIC SCT, together with the incomplete ablation of recipient-derived B cells.

Reduced-intensity allogeneic hematopoietic stem cell transplantation for myelodysplastic syndrome and acute myeloid leukemia with multilineage dysplasia using fludarabine, busulphan, and alemtuzumab (FBC) conditioning

Reduced-intensity conditioned (RIC) hematopoietic stem cell transplantation (HSCT) has improved the accessibility of transplantation in patients previously ineligible. We report the results of allografting following conditioning with fludarabine, busulphan, and alemtuzumab in 62 patients with myelodysplastic syndromes (MDSs) (matched sibling donors [24] or volunteer unrelated donors [VUDs, 38]). The median age for sibling recipients was 56 years (range, 41-70 years) and for VUD recipients, 52 years (range, 22-65 years), with a median follow-up (survivors) of 524 days (range, 93-1392 days) and 420 days (range, 53-1495 days), respectively. The nonrelapse mortality (NRM) at days 100, 200, and 360 was 0%, 5%, and 5%, respectively, for siblings and 11%, 17%, and 21%, respectively, for VUD. The overall survival at one year was 73% for siblings and 71% for VUDs, with a disease-free survival (DFS) of 61% and 59%, respectively. The prognostic significance of the International Prognostic Scoring System (IPSS) was preserved. Of recipients, 86% achieved full-donor chimerism. The cumulative incidence at day 100 of grades III to IV graft-versus-host disease (GVHD) for VUD recipients was 9% and for sibling recipients, 0%. There were 26 patients (16 sibling and 10 VUD) who received donor lymphocyte infusion (DLI) at a median of 273 days (range, 126-1323 days). RIC allogeneic HSCT using this protocol appears to be safe and permits durable donor engraftment. Longer follow-up is required to confirm any potential survival advantage. (Blood. 2004;104:1616-1623)

Posttransplant lymphoproliferative disorder following nonmyeloablative allogeneic stem cell transplantation

Posttransplantation lymphoproliferative disorder (PTLD) is a well-recognized complication of conventional bone marrow/stem cell and solid organ transplantation. However, not much is known about PTLD following the more recently introduced nonmyeloablative allogeneic stem cell transplantation (NMST). This study reports the findings from two cases of PTLD following NMST and compares them to the one previously reported case. The donor origin of the PTLD was determined using short tandem repeat analysis, and B- and T-cell clonalities were evaluated by polymerase chain reaction. Two cases of PTLD evolved in a total of 70 patients who have undergone NMST at our institution from 1999 to 2003. Both patients received conditioning with Fludarabine/Cytoxan/Campath 1H (alemtuzumab, anti-CD52 antibody) and T-cell-depleted donor cells with Campath-1H. Both PTLDs were EBV positive (by immunohistochemistry and in situ hybridization) with diffuse large B-cell lymphoma morphology. Our findings indicate the incidence of PTLD following NMST is 3% (2 of 70 patients from our institution and 1 of 30 from the previously reported case). All three PTLDs arose 6 to 7 months after NMST and were rapidly fatal. The pathology of the PTLD in all cases was donor origin, EBV positive, diffuse large B-cell lymphoma.

Posttransplant lymphoproliferative disease: pathogenesis, monitoring, and therapy

The spectrum of transplant-related lymphoproliferative diseases is expanding to include a variety of neoplasias that typically occur late after transplant including Epstein-Barr virus (EBV)-negative B- and T-cell lymphomas, EBV-positive T-cell lymphoma, myeloma, plasmacytoma, and Hodgkin's disease. New approaches to diagnosis and monitoring based on quantitative polymerase chain reaction for EBV DNA are being explored. What exactly is being measured (the source and character of the viral DNA) remains to be determined, as does the compartment that should be assayed (whole blood, serum, plasma, or lymphocytes). These questions not withstanding, there is an emerging consensus that these technologies will facilitate rapid diagnosis and therapeutic monitoring in the future. A myriad of therapeutic interventions are or will become available. Rituximab, alone or in addition to other therapies, promises a profound change in the landscape with regard to the treatment and perhaps the prevention of posttransplant lymphoproliferative disease. New approaches to adoptive cellular immunotherapy, including use of EBV-specific products from unrelated donors, nonspecifically activated autologous products, and genetically engineered T cells, are all being explored.

Fatal EBV-related post-transplant lymphoproliferative disorder (LPD) after matched related donor nonmyeloablative peripheral blood progenitor cell transplant

A 39-year-old male underwent a nonmyeloablative stem cell transplant (NMAPBPCT) from his HLA-matched sister for recurrent anaplastic large cell lymphoma in CR-2, receiving fludarabine, cyclophosphamide, and rabbit antithymocyte globulin for the preparative therapy. The patient was readmitted on day+33 for persistent culture-negative fevers. He rapidly developed marked elevations of alkaline phosphatase and bilirubin. Liver biopsy showed a periportal infiltrate of large immunoblastic appearing cells. The tumor cells did not stain for CD3/CD20/CD30 and alk protein, but did stain for CD79a/LCA and CD43. In situ hybridization for Epstein-Barr virus (EBV) RNA (EBER 1) was strongly positive in the periportal infiltrating lymphocytes. Fluorescence in situ hybridization (FISH) studies revealed female (XX) cells in the tumor cells and male (XY) in the surrounding hepatic parenchymal cells. The patient developed severe lactic acidosis, oliguric renal failure and expired on day+44. Both donor and patient had positive IgG serologies for EBV VCA and EBNA pretransplant. The donor also had a positive IgM titer for EBV VCA in the pretransplant specimen. The LPD may have been related to the intense immunosuppression of the preparative therapy and the presence of recent EBV infection in the donor.

Is there a role for reduced-intensity haematopoietic stem cell transplantation for indolent non-Hodgkin's lymphoma?

The therapeutic options for the indolent non-Hodgkin's lymphomas have evolved significantly over the years. However, at present, allogeneic haematopoietic stem cell transplantation (HSCT), despite its significant transplant associated complications, is still the only option which may be delivered with curative potential. The debut of reduced-intensity conditioning regimens has extended the applicability of allogeneic transplants to groups of patients ineligible for conventional myeloablative allografts. However, there are still substantial hurdles to overcome, namely that of relapse, graft-versus-host disease and infection. Whilst follow-up is still relatively limited for a disease group with a median survival of up to 10 years, early results are extremely encouraging and further studies are warranted.