Dmitriy Berenzon

The Survival of Memory CD8 T Cells That Is Mediated by IL-15 Correlates with Sustained Protection Against Malaria

Ag-specific memory T cell responses elicited by infections or vaccinations are inextricably linked to long-lasting protective immunity. Studies of protective immunity among residents of malaria endemic areas indicate that memory responses to Plasmodium Ags are not adequately developed or maintained, as people who survive episodes of childhood malaria are still vulnerable to either persistent or intermittent malaria infections. In contrast, multiple exposures to radiation-attenuated Plasmodium berghei sporozoites (Pb γ-spz) induce long-lasting protective immunity to experimental sporozoite challenge. We previously demonstrated that sterile protection induced by Pb γ-spz is MHC class I–dependent and CD8 T cells are the key effectors. IFN-γ+ CD8 T cells that arise in Pb γ-spz–immunized B6 mice are found predominantly in the liver and are sensitive to levels of liver-stage Ag depot and they express CD44hiCD62Llo markers indicative of effector/effector memory phenotype. The developmentally related central memory CD8 T (TCM) cells express elevated levels of CD122 (IL-15Rβ), which suggests that CD8 TCM cells depend on IL-15 for maintenance. Using IL-15–deficient mice, we demonstrate in this study that although protective immunity is inducible in these mice, protection is short-lived, mainly owing to the inability of CD8 TCM cells to survive in the IL-15–deficient milieu. We present a hypothesis consistent with a model whereby intrahepatic CD8 TCM cells, being maintained by IL-15–mediated survival and basal proliferation, are conscripted into the CD8 effector/effector memory T cell pool during subsequent infections.

Polycythemia Vera: An Appraisal of the Biology and Management 10 Years After the Discovery of JAK2 V617F

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm that is associated with a substantial symptom burden, thrombohemorrhagic complications, and impaired survival. A decade after the seminal discovery of an activating mutation in the tyrosine kinase JAK2 in nearly all patients with PV, new treatment options are finally beginning to emerge, necessitating a critical reappraisal of the underlying pathogenesis and therapeutic modalities available for PV. Herein, we comprehensively review clinical aspects of PV including diagnostic considerations, natural history, and risk factors for thrombosis. We summarize recent studies delineating the genetic basis of PV, including their implications for evolution to myelofibrosis and secondary acute myeloid leukemia. We assess the quality of evidence to support the use of currently available therapies, including aspirin, phlebotomy, hydroxyurea, and interferon. We analyze recent studies evaluating the safety and efficacy of JAK inhibitors, such as ruxolitinib, and evaluate their role in the context of other available therapies for PV. This review provides a framework for practicing hematologists and oncologists to make rational treatment decisions for patients with PV.

Chromatin-modifying agents promote the ex vivo production of functional human erythroid progenitor cells

Presently, blood transfusion products (TPs) are composed of terminally differentiated cells with a finite life span. We have developed an ex vivo-generated TP composed of erythroid progenitor cells (EPCs) and precursors cells. Several histone deacetylase inhibitors (HDACIs) were used in vitro to promote the preferential differentiation of cord blood (CB) CD34(+) cells to EPCs. A combination of cytokines and valproic acid (VPA): (1) promoted the greatest degree of EPC expansion, (2) led to the generation of EPCs which were capable of differentiating into the various stages of erythroid development, (3) led to epigenetic modifications (increased H3 acetylation) of promoters for erythroid-specific genes, which resulted in the acquisition of a gene expression pattern characteristic of primitive erythroid cells, and (4) promoted the generation of a TP that when infused into NOD/SCID mice produced mature RBCs containing both human adult and fetal globins as well Rh blood group Ag which persisted for 3 weeks and the retention of human EPCs and erythroid precursor cells within the BM of recipient mice. This ex vivo-generated EPC-TP likely represents a paradigm shift in transfusion medicine because of its potential to continue to generate additional RBCs after its infusion.

Effect of Intensive Chemotherapy on Physical, Cognitive, and Emotional Health of Older Adults with Acute Myeloid Leukemia

To measure short‐term changes in physical and cognitive function and emotional well‐being of older adults receiving intensive chemotherapy for acute myeloid leukemia (AML).

High dose cytarabine, mitoxantrone and l-asparaginase (HAMA) salvage for relapsed or refractory acute myeloid leukemia (AML) in the elderly

Acute myeloid leukemia (AML) is an aggressive malignancy that affects older patients. The role of salvage therapy in the elderly is controversial and there is little data on efficacy. Outcomes for 94 relapsed or refractory AML patients who received salvage HAMA therapy were analyzed. Of the 94 patients 66 were ≥60, including 26 patients ≥70, and 28 were <60 years old. Early mortality (30-day) was 14% (4%<60, 18%≥60 years old). Overall, 27% of patients died during hospitalization or were discharged to hospice (11%<60, 33%≥60 years old). CR/CRi was achieved in 41% of patients (61%<60, 33%≥60 years old). Median survival was 6.1 months (15.7<60, 5.2≥60). Patients ≥60 who achieved a CR/CRi had a median survival of 11.7 months. At 12 months 56% of patients <60 were alive versus 24% of patients ≥60. At 24 months these numbers fell to 40% and 2% respectively. In those <60 years old, 50% went on to allogeneic hematopoietic stem cell transplant (HSCT) whereas 14% of patients in the ≥60 cohort did so. In conclusion, HAMA salvage therapy results in a 33% response rate in patients ≥60 years old with acceptable toxicity.

CD138-negative myeloma cells regulate mechanical properties of bone marrow stromal cells through SDF-1/CXCR4/AKT signaling pathway

As the second most prevalent hematologic malignancy, multiple myeloma (MM) remains incurable and relapses due to intrinsic or acquired drug resistance. Therefore, new therapeutic strategies that target molecular mechanisms responsible for drug resistance are attractive. Interactions of tumor cells with their surrounding microenvironment impact tumor initiation, progression and metastasis, as well as patient prognosis. This cross-talk is bidirectional. Tumor cells can also attract or activate tumor-associated stromal cells by releasing cytokines to facilitate their growth, invasion and metastasis. The effect of myeloma cells on bone marrow stromal cells (BMSCs) has not been well studied. In our study, we found that higher stiffness of BMSCs was not a unique characteristic of BMSCs from MM patients (M-BMSCs). BMSCs from MGUS (monoclonal gammopathy of undetermined significance) patients were also stiffer than the BMSCs from healthy volunteers (N-BMSCs). The stiffness of M-BMSCs was enhanced when cocultured with myeloma cells. In contrast, no changes were seen in myeloma cell-primed MGUS- and N-BMSCs. Interestingly, our data indicated that CD138⁻ myeloma cells, but not CD138⁺ cells, regulated M-BMSC stiffness. SDF-1 was highly expressed in the CD138⁻ myeloma subpopulation compared with that in CD138⁺ cells. Inhibition of SDF-1 using AMD3100 or knocking-down CXCR4 in M-BMSCs blocked CD138⁻ myeloma cells-induced increase in M-BMSC stiffness, suggesting a crucial role of SDF-1/CXCR4. AKT inhibition attenuated SDF-1-induced increases in M-BMSC stiffness. These findings demonstrate, for the first time, CD138⁻ myeloma cell-directed cross-talk with BMSCs and reveal that CD138⁻ myeloma cells regulate M-BMSC stiffness through SDF-1/CXCR4/AKT signaling.

Outcomes and changes in code status of patients with acute myeloid leukemia undergoing induction chemotherapy who were transferred to the intensive care unit

Patients with Acute Myeloid Leukemia (AML) have compromised marrow function and chemotherapy causes further suppression. As a result complications are frequent, and patients may require admission to the intensive care unit (ICU). How codes status changes when these events occur and how those changes influence outcome are largely unknown. Outcomes for adult patients with AML, undergoing induction chemotherapy, and transferred to the ICU between January 2000 and December 2013 were analyzed. 94 patients were included. Median survival was 1.3 months. At 3 and 6 months overall survival (OS) was 27% and 18% respectively. Respiratory failure was the most common reason for transfer to ICU (88%), with 63% requiring mechanical ventilation at transfer. Other reasons included: cardiac arrest (18%), septic shock (17%), hypotension (9%), and acute renal failure (9%). The most frequent interventions were mechanical ventilation in 85%, vasopressors in 62%, and hemodialysis in 30%. Following transfer 55 patients (58%) had a change in code status. Overall, 46 patients (49%) changed from Full Code (FC) to Comfort Care (CC), 7 (7%) from FC to Do Not Resuscitate (DNR), and 2 (2%) from DNR to CC. For the entire cohort, ICU mortality (IM) was 61% and hospital mortality (HM) was 71%. For FC or DNR patients, IM was 30% and HM was 41%. For CC patients, IM was 90% and HM was 100%. Overall, 27 patients (29%) survived to discharge. Of those discharged, 22 (81%) were alive at 3 months and 17 (63%) were alive at 6 months. In conclusion, patients that required ICU admission during induction chemotherapy have a poor prognosis. Code status changed during the ICU stay for the majority of patients and always to a less aggressive status.

Epigenetic Regulation of Normal Hematopoietic Development

Mammalian blood cell production ultimately originates from a pool of pluripotent hematopoietic stem cells (PHSC) which are capable of undergoing self-renewal or commitment to a variety of lineage-committed hematopoietic progenitor cells (HPC) which undergo progressive terminal differentiation, resulting in the production of mature blood cells. Allogeneic cord blood (CB) cells are an important alternative source of marrow-repopulating cells (MRC) which can serve as a stem cell graft for patients with hematological malignancies and blood-related genetic disorders. CB grafts frequently contain less HSC than bone marrow or mobilized peripheral blood grafts which leads to a higher incidence of graft failure and a more prolonged time for hematological reconstitution to occur. The fixed number of HSC within a single CB unit has limited the use of this alternative source of stem cells in adults. Numerous investigators have tried to increase the CB stem cell dose by culturing CB CD34+ cells ex vivo under a variety of conditions in order to shorten the time to engraftment and to make these grafts accessible to adult recipients. We have reported that the expansion of CB CD34+ cells in the presence of cytokines alone alters HSC function leading to the loss of functional HSC after prolonged culture and that the ex vivo sequential addition of chromatin-modifying agents (CMA) to specific cytokine combinations can affect HSC fate decisions resulting in increased numbers of CB MRC. In addition there is presently a need for blood products with rare antigen profiles or for use in alloimmunized individuals. We have attempted to generate such products ex vivo using histone deacetylase inhibitors (HDACI). These data indicate that the HDACI-treated CD34+ cell product was capable of producing human erythroid cells which persisted for least 3 weeks in a xenogeneic transfusion model providing the rationale for further exploring the utility of such ex vivo-generated EPCs as a red cell transfusion product in man. These studies provide insight into the potential utility of CMA as a means of altering the HSC/HPC fate decisions for graft engineering.

A Phase I Study of CPI-613 in Combination with High-Dose Cytarabine and Mitoxantrone for Relapsed or Refractory Acute Myeloid Leukemia

Purpose: CPI-613, a lipoate analogue that inhibits pyruvate dehydrogenase (PDH) and α-ketogluterate dehydrogenase (KGDH), has activity in patients with myeloid malignancies. This study explored the role of mitochondrial metabolism in chemotherapy response and determined the MTD, efficacy, and safety of CPI-613 combined with high-dose cytarabine and mitoxantrone in patients with relapsed or refractory acute myeloid leukemia. Experimental Design: The role of mitochondrial response to chemotherapy was assessed in cell lines and animal models. A phase I study of CPI-613 plus cytarabine and mitoxantrone was conducted in patients with relapsed or refractory AML. Results: Exposure to chemotherapy induced mitochondrial oxygen consumption that depended on PDH. CPI-613 sensitized AML cells to chemotherapy indicating that mitochondrial metabolism is a source of resistance. Loss of p53 did not alter response to CPI-613. The phase I study enrolled 67 patients and 62 were evaluable for response. The overall response rate was 50% (26CR+5CRi/62). Median survival was 6.7 months. In patients over 60 years old, the CR/CRi rate was 47% (15/32) with a median survival of 6.9 months. The response rate for patients with poor-risk cytogenetics also was encouraging with 46% (11/24 patients) achieving a CR or CRi. RNA sequencing analysis of a subset of baseline bone marrow samples revealed a gene expression signature consistent with the presence of B cells in the pretreatment marrow of responders. Conclusions: The addition of CPI-613 to chemotherapy is a promising approach in older patients and those with poor-risk cytogenetics. Clin Cancer Res; 24(9); 2060–73. ©2018 AACR.

Ruxolitinib Therapy Followed by Reduced-Intensity Conditioning for Hematopoietic Cell Transplantation for Myelofibrosis: Myeloproliferative Disorders Research Consortium 114 Study

We evaluated the feasibility of ruxolitinib therapy followed by a reduced-intensity conditioning (RIC) regimen for patients with myelofibrosis (MF) undergoing transplantation in a 2-stage Simon phase II trial. The aims were to decrease the incidence of graft failure (GF) and nonrelapse mortality (NRM) compared with data from the previous Myeloproliferative Disorders Research Consortium 101 Study. The plan was to enroll 11 patients each in related donor (RD) and unrelated donor (URD) arms, with trial termination if ≥3 failures (GF or death by day +100 post-transplant) occurred in the RD arm or ≥6 failures occurred in the URD. A total of 21 patients were enrolled, including 7 in the RD arm and 14 in the URD arm. The RD arm did not meet the predetermined criteria for proceeding to stage II. Although the URD arm met the criteria for stage II, the study was terminated owing to poor accrual and a significant number of failures. In all 19 transplant recipients, ruxolitinib was tapered successfully without significant side effects, and 9 patients (47%) had a significant decrease in symptom burden. The cumulative incidences of GF, NRM, acute graft-versus-host disease (GVHD), and chronic GVHD at 24 months were 16%, 28%, 64%, and 76%, respectively. On an intention-to-treat basis, the 2-year overall survival was 61% for the RD arm and 70% for the URD arm. Ruxolitinib can be integrated as pretransplantation treatment for patients with MF, and a tapering strategy before transplantation is safe, allowing patients to commence conditioning therapy with a reduced symptom burden. However, GF and NRM remain significant.