Total Body Irradiation without Chemotherapy as Conditioning for an Allogeneic Hematopoietic Cell Transplantation for Adult Acute Myeloid Leukemia.

Current therapies for acute myeloid leukemia (AML), failing induction, are rarely effective. We report our experience in 4 patients with AML who received 16 Gy TBI prior to allogeneic hematopoietic cell transplantation (alloHCT), between June 2010 and May 2011. Patients were 20 to 55 years of age, 2 with relapsed disease and 2 with AML failing induction. An HLA-matched graft from related or unrelated donor was infused on day 0. All but one, who received a CD34+-selected graft, received methotrexate and tacrolimus +/- antithymocyte globulin, as GVHD prophylaxis. The other patient received tacrolimus alone. Neutrophil and platelet engraftment occurred at a median of 18 and 14 days, respectively. Patients were discharged at a median of 28 days. There were no unexpected toxicities in the first 30 days. One patient had cytomegalovirus (CMV) viremia and anorexia, at two months. One patient had grade 2 acute GVHD of the skin. One patient developed chronic GVHD of the eyes, mouth, skin, joints, and lung at 4 months. Two patients died from relapse of their leukemia at days 65 and 125. Two patients remain in remission beyond day 1500. 16 Gy TBI followed by an alloHCT for AML, failing induction, is feasible and tolerable.

A high-throughput pharmacoviral approach identifies novel oncolytic virus sensitizers.

Oncolytic viruses (OVs) are promising anticancer agents but like other cancer monotherapies, the genetic heterogeneity of human malignancies can lead to treatment resistance. We used a virus/cell-based assay to screen diverse chemical libraries to identify small molecules that could act in synergy with OVs to destroy tumor cells that resist viral infection. Several molecules were identified that aid in viral oncolysis, enhancing virus replication and spread as much as 1,000-fold in tumor cells. One of these molecules we named virus-sensitizers 1 (VSe1), was found to target tumor innate immune response and could enhance OV efficacy in animal tumor models and within primary human tumor explants while remaining benign to normal tissues. We believe this is the first example of a virus/cell-based "pharmacoviral" screen aimed to identify small molecules that modulate cellular response to virus infection and enhance oncolytic virotherapy.

Enhancement of vaccinia virus based oncolysis with histone deacetylase inhibitors.

Histone deacetylase inhibitors (HDI) dampen cellular innate immune response by decreasing interferon production and have been shown to increase the growth of vesicular stomatitis virus and HSV. As attenuated tumour-selective oncolytic vaccinia viruses (VV) are already undergoing clinical evaluation, the goal of this study is to determine whether HDI can also enhance the potency of these poxviruses in infection-resistant cancer cell lines. Multiple HDIs were tested and Trichostatin A (TSA) was found to potently enhance the spread and replication of a tumour selective vaccinia virus in several infection-resistant cancer cell lines. TSA significantly decreased the number of lung metastases in a syngeneic B16F10LacZ lung metastasis model yet did not increase the replication of vaccinia in normal tissues. The combination of TSA and VV increased survival of mice harbouring human HCT116 colon tumour xenografts as compared to mice treated with either agent alone. We conclude that TSA can selectively and effectively enhance the replication and spread of oncolytic vaccinia virus in cancer cells.

Allogeneic hematopoietic cell transplantation in human immunodeficiency virus-positive patients with hematologic disorders: a report from the center for international blood and marrow transplant research.

The role of allogeneic hematopoietic cell transplantation (alloHCT) in human immunodeficiency virus (HIV)-positive patients is not known. Using the Center for International Blood and Marrow Transplant Research database, we retrospectively evaluated 23 HIV-positive patients undergoing matched sibling donor (n = 19) or unrelated donor (n = 4) alloHCT between 1987 and 2003. The median age at alloHCT was 32 years. Indications for alloHCT were diverse and included malignant (n = 21) and nonmalignant (n = 2) hematologic disorders. Nine patients (39%) underwent transplantation after 1996, the approximate year that highly active antiretroviral therapy became standard treatment. The median time to neutrophil engraftment was 16 days (range, 7 to 30 days), and the cumulative incidences of grade II-IV acute graft-versus-host disease (aGVHD) at 100 days, chronic GVHD (cGVHD), and survival at 2 years were 30% (95% confidence interval [CI] = 14% to 50%), 28% (95% CI = 12% to 48%), and 30% (95% CI = 14% to 50%), respectively. At a median follow-up of 59 months, 6 patients were alive. Survival appears to be better in the patients undergoing alloHCT after 1996; 4 of these 9 patients survived, compared with only 2 of 14 those undergoing transplantation before 1996. These data suggest that alloHCT is feasible for selected HIV-positive patients with malignant and nonmalignant disorders. Prospective studies are needed to evaluate the safety and efficacy of this modality in specific diseases in these patients.

Distinct effector cytokine profiles of memory and naive human B cell subsets and implication in multiple sclerosis.

Although recent animal studies have fuelled growing interest in Ab-independent functions of B cells, relatively little is known about how human B cells and their subsets may contribute to the regulation of immune responses in either health or disease. In this study, we first confirm that effector cytokine production by normal human B cells is context dependent and demonstrate that this involves the reciprocal regulation of proinflammatory and anti-inflammatory cytokines. We further report that this cytokine network is dysregulated in patients with the autoimmune disease multiple sclerosis, whose B cells exhibit a decreased average production of the down-regulatory cytokine IL-10. Treatment with the approved chemotherapeutic agent mitoxantrone reciprocally modulated B cell proinflammatory and anti-inflammatory cytokines, establishing that the B cell cytokine network can be targeted in vivo. Prospective studies of human B cells reconstituting following in vivo depletion suggested that different B cell subsets produced distinct effector cytokines. We confirmed in normal human B cell subsets that IL-10 is produced almost exclusively by naive B cells while the proinflammatory cytokines lymphotoxin and TNF-alpha are largely produced by memory B cells. These results point to an in vivo switch in the cytokine "program" of human B cells transitioning from the naive pool to the memory pool. We propose a model that ascribes distinct and proactive roles to memory and naive human B cell subsets in the regulation of memory immune responses and in autoimmunity. Our findings are of particular relevance at a time when B cell directed therapies are being applied to clinical trials of several autoimmune diseases.

Carrier cell-based delivery of an oncolytic virus circumvents antiviral immunity.

Oncolytic viruses capable of tumor-selective replication and cytolysis have shown early promise as cancer therapeutics. However, the host immune system remains a significant obstacle to effective systemic administration of virus in a clinical setting. Here, we demonstrate the severe negative impact of the adaptive immune response on the systemic delivery of oncolytic vesicular stomatitis virus (VSV) in an immune-competent murine tumor model, an effect mediated primarily by the neutralization of injected virions by circulating antibodies. We show that this obstacle can be overcome by administering virus within carrier cells that conceal viral antigen during delivery. Infected cells were delivered to tumor beds and released virus to infect malignant cells while sparing normal tissues. Repeated administration of VSV in carrier cells to animals bearing metastatic tumors greatly improved therapeutic efficacy when compared with naked virion injection. Whole-body molecular imaging revealed that carrier cells derived from solid tumors accumulate primarily in the lungs following intravenous injection, whereas leukemic carriers disseminate extensively throughout the body. Furthermore, xenogeneic cells were equally effective at delivering virus as syngeneic cells. These findings emphasize the importance of establishing cell-based delivery platforms in order to maximize the efficacy of oncolytic therapeutics.

Outpatient autologous hematopoietic stem cell transplantation for patients with relapsed follicular lymphoma.

Autologous stem cell transplantation (ASCT) has emerged as a viable option for the treatment of relapsed follicular non-Hodgkin's lymphoma. We report on the outpatient experience of 60 patients who underwent ASCT for this condition. The median age was 51 years (30-65). Pre-transplantation conditioning regimens consisted of either etoposide/melphalan/TBI, CBV or BEAM. Patients participated in this transplant program for a median of 20.5 days (14-78), and 58.4% of the total program days were spent in the outpatient setting. Six patients were well enough to be treated solely as outpatients. Ninety percent of patients required at least one inpatient admission (median 7 days), and 70% of first inpatient transfers occurred within the first week following transplant and always before day +12. There were no predictors for prolonged inpatient stays. Febrile neutropenia and gastrointestinal toxicity were the main reasons for inpatient transfers. No outpatient required an urgent admission to the ICU or died in the outpatient setting. The treatment-related mortality at days 30 and 100 was 0 and 1.7%, respectively. The overall and progression-free survivals at 5 years were 65.7 and 56.1%, respectively. Outpatient ASCT with total body irradiation is feasible, safe, and effective for patients with relapsed follicular lymphoma.