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305 result(s) for "Watkins, Benjamin"
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Controversies and expectations for the prevention of GVHD: A biological and clinical perspective
Severe acute and chronic graft versus host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. Historically, cord blood and matched sibling transplantation has been associated with the lowest rates of GVHD. Newer methods have modified the lymphocyte components to minimize alloimmunity, including: anti-thymocyte globulin, post-transplant cyclophosphamide, alpha/beta T cell depletion, and abatacept. These agents have shown promise in reducing severe GVHD, however, can be associated with increased risks of relapse, graft failure, infections, and delayed immune reconstitution. Nonetheless, these GVHD prophylaxis strategies have permitted expansion of donor sources, especially critical for those of non-Caucasian decent who previously lacked transplant options. This review will focus on the biologic mechanisms driving GVHD, the method by which each agent impacts these activated pathways, and the clinical consequences of these modern prophylaxis approaches. In addition, emerging novel targeted strategies will be described. These GVHD prophylaxis approaches have revolutionized our ability to increase access to transplant and have provided important insights into the biology of GVHD and immune reconstitution.
CD28 blockade controls T cell activation to prevent graft-versus-host disease in primates
Controlling graft-versus-host disease (GVHD) remains a major unmet need in stem cell transplantation, and new, targeted therapies are being actively developed. CD28-CD80/86 costimulation blockade represents a promising strategy, but targeting CD80/CD86 with CTLA4-Ig may be associated with undesired blockade of coinhibitory pathways. In contrast, targeted blockade of CD28 exclusively inhibits T cell costimulation and may more potently prevent GVHD. Here, we investigated FR104, an antagonistic CD28-specific pegylated-Fab', in the nonhuman primate (NHP) GVHD model and completed a multiparameter interrogation comparing it with CTLA4-Ig, with and without sirolimus, including clinical, histopathologic, flow cytometric, and transcriptomic analyses. We document that FR104 monoprophylaxis and combined prophylaxis with FR104/sirolimus led to enhanced control of effector T cell proliferation and activation compared with the use of CTLA4-Ig or CTLA4-Ig/sirolimus. Importantly, FR104/sirolimus did not lead to a beneficial impact on Treg reconstitution or homeostasis, consistent with control of conventional T cell activation and IL-2 production needed to support Tregs. While FR104/sirolimus had a salutary effect on GVHD-free survival, overall survival was not improved, due to death in the absence of GVHD in several FR104/sirolimus recipients in the setting of sepsis and a paralyzed INF-γ response. These results therefore suggest that effectively deploying CD28 in the clinic will require close scrutiny of both the benefits and risks of extensively abrogating conventional T cell activation after transplant.
Persistence of Virus Reservoirs in ART-Treated SHIV-Infected Rhesus Macaques after Autologous Hematopoietic Stem Cell Transplant
Despite many advances in AIDS research, a cure for HIV infection remains elusive. Here, we performed autologous hematopoietic stem cell transplantation (HSCT) in three Simian/Human Immunodeficiency Virus (SHIV)-infected, antiretroviral therapy (ART)-treated rhesus macaques (RMs) using HSCs collected prior to infection and compared them to three SHIV-infected, ART-treated, untransplanted control animals to assess the effect of conditioning and autologous HSCT on viral persistence. As expected, ART drastically reduced virus replication, below 100 SHIV-RNA copies per ml of plasma in all animals. After several weeks on ART, experimental RMs received myeloablative total body irradiation (1080 cGy), which resulted in the depletion of 94-99% of circulating CD4+ T-cells, and low to undetectable SHIV-DNA levels in peripheral blood mononuclear cells. Following HSC infusion and successful engraftment, ART was interrupted (40-75 days post-transplant). Despite the observed dramatic reduction of the peripheral blood viral reservoir, rapid rebound of plasma viremia was observed in two out of three transplanted RMs. In the third transplanted animal, plasma SHIV-RNA and SHIV DNA in bulk PBMCs remained undetectable at week two post-ART interruption. No further time-points could be assessed as this animal was euthanized for clinical reasons; however, SHIV-DNA could be detected in this animal at necropsy in sorted circulating CD4+ T-cells, spleen and lymph nodes but not in the gastro-intestinal tract or tonsils. Furthermore, SIV DNA levels post-ART interruption were equivalent in several tissues in transplanted and control animals. While persistence of virus reservoir was observed despite myeloablation and HSCT in the setting of short term ART, this experiment demonstrates that autologous HSCT can be successfully performed in SIV-infected ART-treated RMs offering a new experimental in vivo platform to test innovative interventions aimed at curing HIV infection in humans.
BCMA CAR-T induces complete and durable remission in refractory plasmablastic lymphoma
Plasmablastic lymphoma (PBL) is a rare subtype of aggressive large B-cell lymphoma, with a dismal prognosis despite aggressive therapies. New approaches are needed for those with refractory disease. PBL expresses antigens similar to multiple myeloma (MM), including B-cell maturation antigen (BCMA). Chimeric antigen receptor T-cell (CAR-T) therapy directed against BCMA has shown efficacy for the treatment of heavily pretreated MM with low rates of grades 3 and 4 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in a phase Ib/II trial (A Study of JNJ-68284528, a CAR-T Directed Against BCMA in Participants With Relapsed or Refractory Multiple Myeloma (CARTITUDE-1), NCT03548207). However, data for the use of BCMA CAR-T for treating PBL are lacking.We report a challenging case of multiple refractory PBL that emerged from B-cell acute lymphoblastic leukemia in an adolescent who failed to respond to an allogeneic hematopoietic cell transplant. The patient developed rapidly advancing disease despite withdrawal of immunosuppression, treatment with etoposide, ibrutinib, and daratumumab, prompting consideration of BCMA CAR-T (under emergency investigational new drug (eIND)). The patient achieved a complete remission (CR), without recurrent acute graft versus host disease (GVHD), CRS or ICANS after BCMA CAR-T therapy. BCMA CAR-T expansion was detected in vivo, peaking on day 15. The patient remains in CR for more than a year post CAR-T therapy, supporting consideration of immunotherapy for future patients with refractory PBL, a disease with few treatment options.
Toward a more systematic understanding of water insecurity coping strategies: insights from 11 global sites
IntroductionWater insecurity–the inability to access and benefit from affordable, reliable and safe water for basic needs–is a considerable global health threat. With the urgent need to target interventions to the most vulnerable, accurate and meaningful measurement is a priority. Households use diverse strategies to cope with water insecurity; however, these have not been systematically characterised nor measured. The Food Insecurity Coping Strategies Index has been insightful for targeting nutrition interventions to the most vulnerable. As a first step towards creating an analogous scale for water, this study characterises the largest empirical data set on water insecurity coping strategies and proposes guidance on measuring it using a novel toolkit.MethodsOpen-ended responses on water insecurity coping (n=2301) were collected across 11 sites in 10 low- and middle-income countries in the Household Water InSecurity Experiences (HWISE) Scale validation study. Responses were characterised and compared with behaviours identified in the literature to construct an instrument to systematically assess coping.ResultsWe identified 19 distinct strategies that households used when experiencing water insecurity. These findings, paired with prior literature, were used to develop a Water Insecurity Coping Strategies Assessment Toolkit with guidance on its piloting to assess coping prevalence, frequency and severity.ConclusionsThe widespread occurrence of water insecurity coping strategies underscores the importance of understanding their prevalence and severity. The Water Insecurity Coping Strategies Assessment Toolkit offers a comprehensive approach to evaluate these strategies and inform the design and monitoring of interventions targeting those most vulnerable to water insecurity.
Overlap chronic GVHD is associated with adverse survival outcomes compared to classic chronic GVHD
Chronic graft-versus-host-disease (cGVHD) is divided into two subtypes: classic (absence of acute GVHD features) and overlap cGVHD (‘ocGVHD’), in which both chronic and acute GVHD clinical features are present simultaneously. While worse outcomes with ocGVHD have been reported, there are few recent analyses. We performed a secondary analysis of data from the ABA2 trial ( N  = 185), in which detailed GVHD data were collected prospectively and systematically adjudicated. Analyses included cumulative incidence of classic versus ocGVHD, their specific organ manifestations, global disease severity scores, non-relapse mortality (NRM), disease-free survival (DFS) and overall survival (OS) in these two cGVHD subtypes. Of 92 patients who developed cGVHD, 35 were classified as ocGVHD. The 1-year cumulative incidence, organ involvement, and global severity of classic and ocGVHD were similar between ABA2 patients receiving CNI/MTX+placebo and CNI/MTX+abatacept; thus, cohorts were combined for ocGVHD evaluation. This analysis identified ocGVHD as having significantly higher severity at presentation and at maximum global severity compared to classic cGVHD. OS and DFS were significantly lower for ocGVHD versus classic cGVHD. OcGVHD is associated with increased cGVHD severity scores, and is associated with decreased OS and DFS compared to classic cGVHD, underscoring the high risks with this cGVHD subtype.
Detonation synthesis of carbon nano-onions via liquid carbon condensation
Transit through the carbon liquid phase has significant consequences for the subsequent formation of solid nanocarbon detonation products. We report dynamic measurements of liquid carbon condensation and solidification into nano-onions over ∽200 ns by analysis of time-resolved, small-angle X-ray scattering data acquired during detonation of a hydrogen-free explosive, DNTF (3,4-bis(3-nitrofurazan-4-yl)furoxan). Further, thermochemical modeling predicts a direct liquid to solid graphite phase transition for DNTF products ~200 ns post-detonation. Solid detonation products were collected and characterized by high-resolution electron microscopy to confirm the abundance of carbon nano-onions with an average diameter of ∽10 nm, matching the dynamic measurements. We analyze other carbon-rich explosives by similar methods to systematically explore different regions of the carbon phase diagram traversed during detonation. Our results suggest a potential pathway to the efficient production of carbon nano-onions, while offering insight into the phase transformation kinetics of liquid carbon under extreme pressures and temperatures. Detonation of high explosives can produce many nanocarbon allotropes and morphologies, but the mechanism of formation is challenging to explore. Here the authors observe, by time-resolved small-angle X-ray scattering, a transient liquid phase that precedes the formation of carbon onions.
Coupling neutron reflectivity with cell-free protein synthesis to probe membrane protein structure in supported bilayers
The structure of the p7 viroporin, an oligomeric membrane protein ion channel involved in the assembly and release of the hepatitis C virus, was determined from proteins expressed and inserted directly into supported model lipid membranes using cell-free protein expression. Cell-free protein expression allowed ( i  ) high protein concentration in the membrane, ( ii  ) control of the protein’s isotopic constitution, and ( iii  ) control over the lipid environment available to the protein. Here, we used cell-free protein synthesis to directly incorporate the hepatitis C virus (HCV) p7 protein into supported lipid bilayers formed from physiologically relevant lipids (POPC or asolectin) for both direct structural measurements using neutron reflectivity (NR) and conductance measurements using electrical impedance spectroscopy (EIS). We report that HCV p7 from genotype 1a strain H77 adopts a conical shape within lipid bilayers and forms a viroporin upon oligomerization, confirmed by EIS conductance measurements. This combination of techniques represents a novel approach to the study of membrane proteins and, through the use of selective deuteration of particular amino acids to enhance neutron scattering contrast, has the promise to become a powerful tool for characterizing the protein conformation in physiologically relevant environments and for the development of biosensor applications.
Persistence of Virus Reservoirs in ART-Treated SHIV-Infected Rhesus Macaques after Autologous Hematopoietic Stem Cell Transplant
Despite many advances in AIDS research, a cure for HIV infection remains elusive. Here, we performed autologous hematopoietic stem cell transplantation (HSCT) in three Simian/Human Immunodeficiency Virus (SHIV)-infected, antiretroviral therapy (ART)-treated rhesus macaques (RMs) using HSCs collected prior to infection and compared them to three SHIV-infected, ART-treated, untransplanted control animals to assess the effect of conditioning and autologous HSCT on viral persistence. As expected, ART drastically reduced virus replication, below 100 SHIV-RNA copies per ml of plasma in all animals. After several weeks on ART, experimental RMs received myeloablative total body irradiation (1080 cGy), which resulted in the depletion of 94-99% of circulating CD4+ T-cells, and low to undetectable SHIV-DNA levels in peripheral blood mononuclear cells. Following HSC infusion and successful engraftment, ART was interrupted (40-75 days post-transplant). Despite the observed dramatic reduction of the peripheral blood viral reservoir, rapid rebound of plasma viremia was observed in two out of three transplanted RMs. In the third transplanted animal, plasma SHIV-RNA and SHIV DNA in bulk PBMCs remained undetectable at week two post-ART interruption. No further time-points could be assessed as this animal was euthanized for clinical reasons; however, SHIV-DNA could be detected in this animal at necropsy in sorted circulating CD4+ T-cells, spleen and lymph nodes but not in the gastro-intestinal tract or tonsils. Furthermore, SIV DNA levels post-ART interruption were equivalent in several tissues in transplanted and control animals. While persistence of virus reservoir was observed despite myeloablation and HSCT in the setting of short term ART, this experiment demonstrates that autologous HSCT can be successfully performed in SIV-infected ART-treated RMs offering a new experimental in vivo platform to test innovative interventions aimed at curing HIV infection in humans.