Citations

AbstractClinical trials of novel salvage therapies have encouraging outcomes for relapsed/refractory transplant‐eligible classic Hodgkin lymphoma (R/R cHL) but comparison with conventional chemotherapy is lacking. Herein, we report the final analysis of a multicenter retrospective cohort of R/R cHL assessing outcomes by type of salvage therapy before autologous stem cell transplant (ASCT). R/R cHL patients who underwent ASCT at 14 institutions across the United States were included. Outcomes were compared among patients receiving conventional chemotherapy, brentuximab vedotin (BV) + chemotherapy, BV alone, and a checkpoint inhibitor (CPI)‐based regimens before ASCT. Study endpoints included event‐free survival (EFS), progression‐free survival (PFS), and overall survival (OS). All endpoints are defined from relapse. Of 936 patients, 728 received conventional chemotherapy, 73 received BV + chemotherapy, 70 received BV alone, and 65 received CPI‐based regimens prior to ASCT. When adjusted for time to relapse, pre‐ASCT response and use of BV maintenance, patients receiving CPI‐based regimens had superior 2‐year EFS compared to conventional chemotherapy, BV + chemotherapy, and BV alone (79.7, 49.6, 62.3, and 36.9%, respectively, p < .0001). Among 649 patients transplanted after 1 line of salvage therapy, CPI‐based regimens were associated with superior 2‐year PFS compared to conventional chemotherapy (98% vs. 68.8%, hazard ratio: 0.1, 95% confidence interval: 0.03–0.5, p < .0001). OS did not differ by pre‐ASCT salvage regimen. In this large multicenter retrospective study, CPI‐based regimens improved EFS and PFS compared to other salvage regimens independent of pre‐ASCT response. These data support earlier sequencing of CPI‐based regimens in R/R cHL in the pre‐ASCT setting.

Abstract Neurofilament light chain, a putative measure of neuronal damage, is measurable in blood and CSF and is predictive of cognitive function in individuals with Alzheimer’s disease. There has been limited prior work linking neurofilament light and functional connectivity, and no prior work has investigated neurofilament light associations with functional connectivity in autosomal dominant Alzheimer’s disease. Here, we assessed relationships between blood neurofilament light, cognition, and functional connectivity in a cross-sectional sample of 106 autosomal dominant Alzheimer’s disease mutation carriers and 76 non-carriers. We employed an innovative network-level enrichment analysis approach to assess connectome-wide associations with neurofilament light. Neurofilament light was positively correlated with deterioration of functional connectivity within the default mode network and negatively correlated with connectivity between default mode network and executive control networks, including the cingulo-opercular, salience, and dorsal attention networks. Further, reduced connectivity within the default mode network and between the default mode network and executive control networks was associated with reduced cognitive function. Hierarchical regression analysis revealed that neurofilament levels and functional connectivity within the default mode network and between the default mode network and the dorsal attention network explained significant variance in cognitive composite scores when controlling for age, sex, and education. A mediation analysis demonstrated that functional connectivity within the default mode network and between the default mode network and dorsal attention network partially mediated the relationship between blood neurofilament light levels and cognitive function. Our novel results indicate that blood estimates of neurofilament levels correspond to direct measurements of brain dysfunction, shedding new light on the underlying biological processes of Alzheimer’s disease. Further, we demonstrate how variation within key brain systems can partially mediate the negative effects of heightened total serum neurofilament levels, suggesting potential regions for targeted interventions. Finally, our results lend further evidence that low-cost and minimally invasive blood measurements of neurofilament may be a useful marker of brain functional connectivity and cognitive decline in Alzheimer’s disease.

Human spaceflight is associated with several health-related issues as a result of long-term exposure to microgravity, ionizing radiation, and higher levels of psychological stress. Frequent reported skin problems in space include rashes, itches, and a delayed wound healing. Access to space is restricted by financial and logistical issues; as a consequence, experimental sample sizes are often small, which limits the generalization of the results. Earth-based simulation models can be used to investigate cellular responses as a result of exposure to certain spaceflight stressors. Here, we describe the development of an in vitro model of the simulated spaceflight environment, which we used to investigate the combined effect of simulated microgravity using the random positioning machine (RPM), ionizing radiation, and stress hormones on the wound-healing capacity of human dermal fibroblasts. Fibroblasts were exposed to cortisol, after which they were irradiated with different radiation qualities (including X-rays, protons, carbon ions, and iron ions) followed by exposure to simulated microgravity using a random positioning machine (RPM). Data related to the inflammatory, proliferation, and remodeling phase of wound healing has been collected. Results show that spaceflight stressors can interfere with the wound healing process at any phase. Moreover, several interactions between the different spaceflight stressors were found. This highlights the complexity that needs to be taken into account when studying the effect of spaceflight stressors on certain biological processes and for the aim of countermeasures development.

AbstractBackgroundPreoperative anemia is common and associated with adverse postoperative outcomes. Assessment of hemoglobin concentrations may facilitate optimization prior to surgery. However, phlebotomy‐based hemoglobin measurement may contribute to patient discomfort and iatrogenic blood loss, which makes non‐invasive hemoglobin estimation attractive in this setting.Study Design and MethodsThis is a prospective study of adult patients presenting for preoperative evaluation before elective surgery at a tertiary care medical center. The Masimo Pronto Pulse CO‐Oximeter was utilized to estimate blood hemoglobin concentrations (SpHb), which were then compared with hemoglobin concentrations obtained via complete blood count. Receiver operating curves were used to identify SpHb values maximizing specificity for anemia detection while meeting a minimum sensitivity of 80%.ResultsA total of 122 patients were recruited with a median (interquartile range) age of 66 (58, 72) years. SpHb measurements were obtained in 112 patients (92%). SpHb generally overestimated hemoglobin with a mean (± 1.96 × standard deviation) difference of 0.8 (−2.2, 3.9) g/dL. Preoperative anemia, defined by hemoglobin <12.0 g/dL in accordance with institutional protocol, was present in 22 patients (20%). The optimal SpHb cut‐point to identify anemia was 13.5 g/dL: sensitivity 86%, specificity 81%, negative predictive value 96%, and positive predictive value 53%. Utilizing this cut‐point, 60% (73/122) of patients could have avoided phlebotomy‐based hemoglobin assessment, while an anemia diagnosis would have been missed in <3% (3/122).ConclusionThe use of SpHb devices for anemia screening in surgical patients is feasible with the potential to reliably rule‐out anemia despite limited accuracy.

Abstract Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can result in a cytokine storm that is associated with poor outcomes in patients. The activation of a NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome following SARS-CoV-2 infection has been shown to play a major role in inflammatory immune responses. In this study, we show that open reading frame 8 (ORF8) protein is abundantly secreted as a glycoprotein in vitro. The glycosylated ORF8 stimulates human CD14+/CD16+ monocytes to cause upregulation of proinflammatory cytokine production and cell surface marker expression within 24 hours. The data suggests that stimulation of human monocytes by ORF8 is not receptor mediated. Rather, ORF8 is likely phagocytosed by human monocytes. ORF8 then stimulates the monocytes by independently binding to the NACHT and LRR domains of the NLRP3 protein. Pharmacologic inhibition of NLRP3 significantly diminished the production of pro-inflammatory cytokines from ORF8-stimulated human monocytes. Finally, this study shows that the ORF8 protein is also secreted in patients with newly diagnosed coronavirus disease 2019 (COVID-19). Levels of ORF8 in the blood of patients diagnosed with COVID-19 correlated with disease mortality and trajectory of disease. ORF8 stimulation of monocytes causes pro-inflammatory cytokine production that leads to the development of severe COVID-19.

Abstract Cytotoxic T cell infiltration into the central nervous system (CNS) is required for clearance of pathogen or tumor. Whether microglia, the resident innate immune cells of the brain, are involved in orchestrating CD8 T cell infiltration of the brain in an antigen dependent manner remains to be elucidated. We hypothesized that antigen presentation by major histocompatibility complex (MHC) class I molecules expressed by microglia is required to orchestrate antigen specific CD8 T cell infiltration into the brain parenchyma. To test this hypothesis, we generated a novel tamoxifen-inducible microglial MHC class I conditional knockout mouse (CX3CR1-creERT2H-2Kb cKO). In these mice, administration of tamoxifen mediates deletion of the H-2Kbmolecule in cells expressing CX3CR1. Short-lived peripheral CX3CR1+ cells repopulate within 4–6 weeks after tamoxifen treatment and restore expression of H-2Kb, leaving only long-lived microglia deficient for MHC class I. We challenged these mice with intracranial infection of Theiler’s murine encephalomyelitis virus expressing the model antigen ovalbumin (TMEV-OVA) to assess antigen specific CD8 T cell responses within the brain parenchyma. In microglia MHC I cKO mice, the frequency of brain infiltrating OVA-specific CD8 T cells was attenuated while the frequency of intravascular OVA-specific CD8 T cells was increased when compared to cre− littermate controls. These results suggest that microglial antigen presentation is important for antigen specific CD8 T cell infiltration into the brain parenchyma. These studies directly address the critical role of microglial MHC class I on antigen specific CD8 T cell responses to an in vivo neuroinflammatory insult.

Abstract Immunotherapeutic approaches to the treatment of melanoma have been hindered by the emergence of melanoma variants and relapsing tumors that are antigenically distinct and hence not recognized by memory cells. We have identified an antibody that has proven effective for the treatment of a mouse model of melanoma, B16. B7DC-XAb is an antibody that specifically binds to dendritic cells and increases their antigen uptake capabilities and their ability to activate T-cells and generates strong cytotoxic lymphocyte responses. We are using B16 tumor cell lysates along with this antibody as an adjuvant for the generation of robust and rapid CTL responses to B16 melanoma. Treatment of B16 tumor challenged mice with B7DC-XAb leads to a CTL response that recognizes an epitope from tyrosinase related protein-1. Subsequent B16-OVA tumor challenge results in a lack of protection, against this related but antigenically unique tumor. Therefore we have used tumor cell lysates in conjunction with antibody treatment in an attempt to broaden the specificity against the melanoma lines. Therapeutic treatment with B16 tumor cell lysate and B7DC-XAb leads to clearance of a 6 day established B16 tumor. Further, re-challenge 30 days later with B16-OVA is also cleared demonstrating an enhanced memory response, to this antigenically distinct tumor. Further studies will determine which antigens are responsible for initiating this response as well as those that are important for tumor clearance.

Abstract CD8 T cell responses are essential for clearance of infections and tumors in the central nervous system (CNS). Under homeostatic conditions, T cell access to the CNS parenchyma is restricted. An intricate process of T cell reactivation by antigen presenting cells (APCs) at CNS barriers is thought to allow activated antigen-specific T cells to infiltrate the parenchyma during neurological disease. The role of CNS-resident APCs during CD8 T cell infiltration of the CNS parenchyma is unclear. We hypothesized that microglia and brain-associated macrophages (BAMs) are APCs critical for antigen specific CD8 T cell reactivation and CNS infiltration. To test this hypothesis, we generated mice with tamoxifen-inducible deletion of MHC class I on microglia and BAMs by crossing CX3CR1creER mice with H-2Db fl/fl mice (Db cKO). We challenged these mice with intracranial infection of Theiler’s murine encephalomyelitis virus (TMEV), which generates a robust CD8 T cell response against a Db restricted antigen (VP2121–130) in the brain. At 7 days post infection (dpi), brain infiltrating Db:VP2-specific CD8 T cells were reduced in Db cKO mice compared to control, while peripheral priming of CD8 T cells was unaffected. Unexpectedly, inflammatory monocytes infiltrating the brain at 7 dpi were also reduced in Db cKO mice, indicating a role for microglia/BAMs and CD8 T cells in recruitment of inflammatory monocytes. Db cKO mice were able to clear virus, indicating functional antiviral responses against TMEV occur despite reduced immune infiltration. These results demonstrate that local antigen presentation by microglia and BAMs facilitates inflammatory monocyte recruitment and antigen-specific CD8 T cell responses in the brain after TMEV infection.

Abstract We have previously shown that vesicular stomatitis virus (VSV) vectors encoding truncated tumor antigens, NRAS, Cytochrome C1, and TYRP1, prime superior systemic anti-tumor T cell responses and provide enhanced therapeutic benefit compared to vectors expressing full-length forms of the protein. Mapping of the roughly 20 amino C-terminal truncated regions onto structural domains of each protein suggested the truncations disrupted the stability and localization of each protein. Indeed, immunofluorescent staining and radiolabeled pulse chase found that truncated TYRP1 (ΔTYRP1) had an altered localization pattern and a significantly reduced half-life compared to full-length TYRP1. Thus, we hypothesized that expression of destabilized antigens from VSV would provide superior therapy compared to expression of wild-type antigens. To test this, we introduced point-mutations into structurally important domains of the model antigen ovalbumin (OVA). We identified one mutant which was significantly destabilized (OVAmut), which resulted in enhanced MHC Class I presentation of the immunogenic SIINFEKL epitope on transfected cell in vitro. Expression of OVAmut resulted in better recognition by cognate CD8 OTI T cells, enhanced T cell activation, proliferation, and effector cytokine production. Finally, a VSV vector expressing OVmut was better able to prime OTI T cells in vitro as well as in vivo. Ongoing studies aim to identify the changes in the quantity and repertoire of immunogenic epitopes presented from cells infected with VSV vectors expressing destabilized antigens. These studies provide insight into the capacity of the VSV platform to successfully encode unstable antigens with the goal improve immunogenic responses.