EBNA3B-deficient EBV promotes B cell lymphomagenesis in humanized mice and is found in human tumors

Epstein-Barr virus (EBV) persistently infects more than 90% of the human population and is etiologically linked to several B cell malignancies, including Burkitt lymphoma (BL), Hodgkin lymphoma (HL), and diffuse large B cell lymphoma (DLBCL). Despite its growth transforming properties, most immune-competent individuals control EBV infection throughout their lives. EBV encodes various oncogenes, and of the 6 latency-associated EBV-encoded nuclear antigens, only EBNA3B is completely dispensable for B cell transformation in vitro. Here, we report that infection with EBV lacking EBNA3B leads to aggressive, immune-evading monomorphic DLBCL-like tumors in NOD/SCID/γc-/- mice with reconstituted human immune system components. Infection with EBNA3B-knockout EBV (EBNA3BKO) induced expansion of EBV-specific T cells that failed to infiltrate the tumors. EBNA3BKO-infected B cells expanded more rapidly and secreted less T cell-chemoattractant CXCL10, reducing T cell recruitment in vitro and T cell-mediated killing in vivo. B cell lines from 2 EBV-positive human lymphomas encoding truncated EBNA3B exhibited gene expression profiles and phenotypic characteristics similar to those of tumor-derived lines from the humanized mice, including reduced CXCL10 secretion. Screening EBV-positive DLBCL, HL, and BL human samples identified additional EBNA3B mutations. Thus, EBNA3B is a virus-encoded tumor suppressor whose inactivation promotes immune evasion and virus-driven lymphomagenesis.     

Transplantation of anergic histoincompatible bone marrow allografts.

BACKGROUND: Successful allogeneic bone marrow transplantation relies on global immunosuppression or elimination of T cells. In contrast, the induction of anergy can inactivate specific sets of alloreactive T cells in the donor marrow. Previous work has shown that anergy can be induced by blocking the interaction of the B7 molecule on the surface of antigen-presenting cells with the CD28 molecule on the surface of T cells, thus preventing key signaling events essential for the activation of T cells. To investigate the feasibility of this approach with respect to transplantation of histoincompatible bone marrow, we undertook a clinical trial of ex vivo induction of anergy in T cells present in donor marrow to recipient alloantigens. METHODS: Outcomes in 12 transplant recipients were evaluated. The recipients' peripheral-blood lymphocytes were collected before myeloablation and served as alloantigen-presenting cells. To induce alloantigen-specific anergy, bone marrow from a donor mismatched with the recipient for one HLA haplotype was cocultured with irradiated cells from the recipient for 36 hours in the presence of CTLA-4-Ig, an agent that inhibits B7:CD28-mediated costimulation. After conventional myeloablation and immunoprophylaxis, the treated donor cells were transfused into the recipient. RESULTS: After the induction of anergy, the frequency of T cells capable of recognizing alloantigens of the recipient in donor marrow was sharply reduced (P<0.001), whereas the responsiveness to alloantigens from persons unrelated to the recipient or the donor was unaffected (P=0.51). In the 11 patients who could be evaluated, the haploidentical bone marrow cells engrafted. Of these 11 patients, 3 had acute graft-versus-host disease (GVHD) confined to the gastrointestinal tract. No deaths were attributable to GVHD. Five of the 12 patients were alive and in remission 4.5 to 29 months after transplantation. CONCLUSIONS: Donor bone marrow treated ex vivo to induce anergy to alloantigens from the recipient can reconstitute hematopoiesis in vivo with a relatively low risk of GVHD.     

Autologous bone marrow transplantation for marginal zone non-Hodgkin's lymphoma

The marginal zone non-Hodgkin's lymphomas are a recently defined group of related low-grade B cell malignancies whose natural history is heterogeneous. The optimal therapy is often unclear, particularly for the subset of patients with disseminated disease that behaves aggressively. We have retrospectively analyzed the outcomes of 11 patients with chemosensitive but disseminated marginal zone lymphomas who underwent uniform conditioning with cyclophosphamide and total body irradiation followed by bone marrow transplantation (BMT) with anti-B cell monoclonal antibody-purged autologous bone marrow between January 1994 and September 1999. All patients had stage IV disease and received multiple chemotherapy regimens prior to autologous BMT. Only 36% were in complete remission at the time of bone marrow harvest, and 36% had overt bone marrow infiltration at that time. Two treatment-related deaths occurred between 100 days and 6 months. Three patients relapsed and died of disease. One patient developed and died of myelodysplasia. Five patients remain in continuous complete remission at a median follow-up of 52 months (45%). The median progression-free survival for these patients was 56 months, with median overall survival 58 months. The only significant predictor of disease-free and overall survival was age at the time of transplant; no patient under 45 at the time of transplant has relapsed or died of any cause (P = 0.003). Outcomes of autologous BMT in patients with disseminated marginal zone NHL are similar to those in follicular NHL, and suggest that certain patients may experience prolonged disease-free survival.     

Pharmacokinetics and tolerability of BAY41-6551 in subjects with chronic kidney disease

Abstract Background: BAY41-6551, a drug-device combination in development for adjunctive treatment of Gram-negative pneumonia in mechanically ventilated patients, consists of amikacin formulated for inhalation coupled with the Pulmonary Drug Delivery System (PDDS) Clinical aerosol delivery platform. This study evaluated safety, tolerability, and pharmacokinetics (PK) of BAY41-6551 in subjects with chronic kidney disease (CKD). Methods: Single doses of BAY41-6551 (400?mg amikacin) were administered using the PDDS Clinical handheld device to six subjects with mild-to-moderate (Group 1) and six subjects with severe renal impairment (Group 2). Seven subjects with end-stage renal disease (ESRD; Group 3) received single doses of BAY41-6551 on days 1 and 9, with hemodialysis (HD) scheduled 24?h postdose on day 1 and 3?h postdose on day 9. PK analysis was performed on serum, urine, and dialysate samples (Group 3). Results: Individual serum amikacin concentrations in Groups 1 and 2 were below 6?mg/L at all times [mean maximum serum drug concentration (C(max)) 0.94?mg/L and 2.46?mg/L, respectively). In Group 3, serum amikacin concentrations decreased after each HD session, and amikacin area under the serum concentration-time curve from zero to 72?h (AUC(72)) and C(max) values were lower on day 9 than on day 1 (mean AUC(72) 71.5?mg?·?h/L vs. 151.5?mg?·?h/L; mean C(max) 2.09?mg/L vs. 6.16?mg/L). The amounts of amikacin removed by HD and the dialysate clearance rates were similar on days 1 and 9. No serious adverse events were reported. Conclusions: Single doses of BAY41-6551 were well tolerated in subjects with CKD. HD effectively removed amikacin from serum in subjects with ESRD, and the timing relative to BAY41-6551 administration was an important determinant of systemic amikacin exposure. Nevertheless, standard precautionary measures for intravenous amikacin should apply for patients receiving BAY41-6551, and dose adjustments and/or dialysis should be considered for subjects with severe renal impairment.     

Immune dysfunction in chronic lymphocytic leukemia: the role for immunotherapy

A key feature of the clinical course of chronic lymphocytic leukemia (CLL) is that it induces a state of immunosuppression, causing increased susceptibility to infections and failure of anti-tumor immune responses. Cytotoxic chemotherapy still forms the mainstay of most current treatment regimens, but is not curative, and its lack of specificity means that it also targets normal immune cells, exacerbating this immunosuppression. This can result in effective treatments being limited by infectious complications, particularly in the elderly who comprise the majority of patients with this disease. Immunotherapy potentially offers a way out of this dilemma, due to its improved specificity and ability to enhance immune responses to both the tumor and infectious agents. There has been a dramatic increase in the range of available immunotherapeutic options over the past decade, and many are now in the process of making the transition to the clinic. This review will discuss both the immune defect in CLL, and emerging immunotherapies, including CD40 ligand gene therapy, lenalidomide, CLL vaccines, CXCR4 antagonists, and adoptive cellular immunotherapies such as chimeric antigen receptor modified T-cells.     

Variations of the ataxia telangiectasia mutated gene in patients with chronic lymphocytic leukemia lack substantial impact on progression-free survival and overall survival: a Cancer and Leukemia Group B study

The impact of mutation of the ATM (ataxia telangiectasia mutated) gene in chronic lymphocytic leukemia (CLL) treatment outcome has not been examined. We studied ATM mutations in 73 patients treated with fludarabine and rituximab. ATM gene mutation analysis was performed using temperature gradient capillary electrophoresis. The impact of detected variants on overall survival (OS) and progression-free survival (PFS) was tested with proportional hazards models. None of the 73 patients demonstrated truncating ATM mutations; 17 (23%, 95% confidence interval 14-35%) had non-silent variants (ATM-NSVs), including 13 known ATM polymorphisms and four missense variants. ATM-NSVs were not significantly associated with any baseline characteristics including immunoglobulin heavy chain variable gene (IGVH) status. In multivariable models, no significant differences in complete response (p =0.70), PFS (p =0.59) or OS (p =0.13) were observed. Our data indicate that truncating ATM mutations are rare in patients with CLL. Furthermore, in this dataset, these non-silent variants had limited impact on PFS and OS.     

T-cell function in chronic lymphocytic leukaemia

According to the immune-surveillance hypothesis, cancer cells evolve strategies to evade or suppress the immune system as part of the development of this disease. The malignant B-cells of chronic lymphocytic leukaemia are prime examples of this premise, having been shown to generate a variety of ways of suppressing T-cell anti-tumour immune responses and these are summarized here. These mechanisms range from impairment of antigen presentation by the tumour cells themselves, to suppression of the immune microenvironment by contact dependent pathways and alterations in the cytokine milieu. By understanding these defects, novel targeted therapies can be developed with the aim of restoring T-cell function. Indeed, some of the recent advances in the treatment of chronic lymphocytic leukaemia have been demonstrated to have profound immunomodulatory effects, repairing these defects in T-cell function.     

DNA‐damaging activity in ethanol‐soluble fractions of feces from New Zealand groups at varying risks of colorectal cancer

Using repair‐proficient and repair‐deficient strains of E.coli, we investigated the application of a liquid incubation assay to measure the DNA‐damaging activity of ethanol‐soluble fecal extracts. This method appears to be suitable for the study of a wide range of sample types. It was used to measure the DNA‐modifying activity of ethanol‐soluble fecal extracts from a group of European colorectal cancer patients. Data were compared with those from Europeans of similar age and sex distribution who did not have bowel cancer. We also studied groups of Maoris, Samoans, and European Seventh‐Day Adventists who followed an ovo‐lacto vegetarian diet. There are significant levels of DNA‐modifying materials in the feces of many Europeans on a mixed diet, regardless of whether or not they have cancer. The number of positive samples was less in the Polynesian groups, and there were no samples that could be unequivocally scored as positive in the Seventh‐Day Adventist groups. We conclude that diet can significantly reduce the level of ethanol‐soluble mutagens, at least in New Zealand Europeans. The data may provide an explanation for the reduced incidence of bowel cancer in Seventh‐Day Adventist groups.     

Phase I study of recombinant human CD40 ligand in cancer patients.

PURPOSE: To determine the toxicity, maximum-tolerated dose (MTD), and pharmacokinetics of recombinant human CD40 ligand (rhuCD40L) (Avrend; Immunex Corp, Seattle, WA), suggested in preclinical studies to mediate cytotoxicity against CD40-expressing tumors and immune stimulation. PATIENTS AND METHODS: Patients with advanced solid tumors or intermediate- or high-grade non-Hodgkin's lymphoma (NHL) received rhuCD40L subcutaneously daily for 5 days in a phase I dose-escalation study. Subsequent courses were given until disease progression. RESULTS: Thirty-two patients received rhuCD40L at three dose levels. A total of 65 courses were administered. The MTD was 0.1 mg/kg/d based on dose-related but transient elevations of serum liver transaminases. Grade 3 or 4 transaminase elevations occurred in 14%, 28%, and 57% of patients treated at 0.05, 0.10, and 0.15 mg/kg/d, respectively. Other toxicities were mild to moderate. At the MTD, the half-life of rhuCD40L was calculated at 24.8 +/- 22.8 hours. Two patients (6%) had a partial response on study (one patient with laryngeal carcinoma and one with NHL). For the patient with laryngeal cancer, a partial response was sustained for 12 months before the patient was taken off therapy and observed on no additional therapy. Three months later, the patient was found to have a complete response and remains biopsy-proven free of disease at 24 months. Twelve patients (38%) had stable disease after one course, which was sustained in four patients through four courses. CONCLUSION: The MTD of rhuCD40L when administered subcutaneously daily for 5 days was defined by transient serum elevations in hepatic transaminases. Encouraging antitumor activity, including a long-term complete remission, was observed. Phase II studies are warranted.     

Echocardiography and Cardiac Magnetic Resonance‐Based Feature Tracking in the Assessment of Myocardial Mechanics in Tetralogy of Fallot: An Intermodality Comparison

We investigated intermodality agreements of strains from two‐dimensional echocardiography (2DE) and cardiac magnetic resonance (CMR) feature tracking (FT) in the assessment of right (RV) and left ventricular (LV) mechanics in tetralogy of Fallot (TOF). Patients were prospectively studied with 2DE and CMR performed contiguously. LV and RV strains were computed separately using 2DE and CMR‐FT. Segmental and global longitudinal strains (GLS) for the LV and RV were measured from four‐chamber views; LV radial (global radial strain [GRS]) and circumferential strains (GCS) measured from short‐axis views. Intermodality and interobserver agreements were examined. In 40 patients (20 TOF, mean age 23 years and 20 adult controls), LV, GCS showed narrowest intermodality limits of agreement (mean percentage error 9.5%), followed by GLS (16.4%). RV GLS had mean intermodality difference of 25.7%. GLS and GCS had acceptable interobserver agreement for the LV and RV with both 2DE and CMR‐FT, whereas GRS had high interobserver and intermodality variability. In conclusion, myocardial strains for the RV and LV derived using currently available 2DE and CMR‐FT software are subject to considerable intermodality variability. For both modalities, LV GCS, LV GLS, and RV GLS are reproducible enough to warrant further investigation of incremental clinical merit.