The NF1+/- Immune Microenvironment: Dueling Roles in Neurofibroma Development and Malignant Transformation.

Neurofibromatosis type 1 (NF1) is a common genetic disorder resulting in the development of both benign and malignant tumors of the peripheral nervous system. NF1 is caused by germline pathogenic variants or deletions of the NF1 tumor suppressor gene, which encodes the protein neurofibromin that functions as negative regulator of p21 RAS. Loss of NF1 heterozygosity in Schwann cells (SCs), the cells of origin for these nerve sheath-derived tumors, leads to the formation of plexiform neurofibromas (PNF)-benign yet complex neoplasms involving multiple nerve fascicles and comprised of a myriad of infiltrating stromal and immune cells. PNF development and progression are shaped by dynamic interactions between SCs and immune cells, including mast cells, macrophages, and T cells. In this review, we explore the current state of the field and critical knowledge gaps regarding the role of NF1(Nf1) haploinsufficiency on immune cell function, as well as the putative impact of Schwann cell lineage states on immune cell recruitment and function within the tumor field. Furthermore, we review emerging evidence suggesting a dueling role of Nf1+/- immune cells along the neurofibroma to MPNST continuum, on one hand propitiating PNF initiation, while on the other, potentially impeding the malignant transformation of plexiform and atypical neurofibroma precursor lesions. Finally, we underscore the potential implications of these discoveries and advocate for further research directed at illuminating the contributions of various immune cells subsets in discrete stages of tumor initiation, progression, and malignant transformation to facilitate the discovery and translation of innovative diagnostic and therapeutic approaches to transform risk-adapted care.

Under-five mortality before and after implementation of the Liberia National Community Health Assistant (NCHA) program: A study protocol.

Between 2018 and 2022 the Liberian Government implemented the National Community Health Assistant (NCHA) program to improve provision of maternal and child health care to underserved rural areas of the country. Whereas the contributions of this and similar community health worker (CHW) based healthcare programs have been associated with improved process measures, the impact of a governmental CHW program at scale on child mortality has not been fully established. We will conduct a cluster sampled, community-based survey with landmark event calendars to retrospectively assess child births and deaths among all children born to women in the Grand Bassa District of Liberia. We will use a mixed effects Cox proportional hazards model, taking advantage of the staggered program implementation in Grand Bassa districts over a period of 4 years to compare rates of under-5 child mortality between the pre- and post-NCHA program implementation periods. This study will be the first to estimate the impact of the Liberian NCHA program on under-5 mortality.

Spatial Gene-Expression Profiling Unveils Immuno-oncogenic Programs of NF1-Associated Peripheral Nerve Sheath Tumor Progression.

PURPOSE: Plexiform neurofibromas (PNF) are benign peripheral nerve sheath tumors (PNST) associated with neurofibromatosis type 1 (NF1). Despite similar histologic appearance, these neoplasms exhibit diverse evolutionary trajectories, with a subset progressing to malignant peripheral nerve sheath tumor (MPNST), the leading cause of premature death in individuals with NF1. Malignant transformation of PNF often occurs through the development of atypical neurofibroma (ANF) precursor lesions characterized by distinct histopathologic features and CDKN2A copy-number loss. Although genomic studies have uncovered key driver events promoting tumor progression, the transcriptional changes preceding malignant transformation remain poorly defined. EXPERIMENTAL DESIGN: Here we resolve gene-expression profiles in PNST across the neurofibroma-to-MPNST continuum in NF1 patients and mouse models, revealing early molecular features associated with neurofibroma evolution and transformation. RESULTS: Our findings demonstrate that ANF exhibit enhanced signatures of antigen presentation and immune response, which are suppressed as malignant transformation ensues. MPNST further displayed deregulated survival and mitotic fidelity pathways, and targeting key mediators of these pathways, CENPF and BIRC5, disrupted the growth and viability of human MPNST cell lines and primary murine Nf1-Cdkn2a-mutant Schwann cell precursors. Finally, neurofibromas contiguous with MPNST manifested distinct alterations in core oncogenic and immune surveillance programs, suggesting that early molecular events driving disease progression may precede histopathologic evidence of malignancy. CONCLUSIONS: If validated prospectively in future studies, these signatures may serve as molecular diagnostic tools to augment conventional histopathologic diagnosis by identifying neurofibromas at high risk of undergoing malignant transformation, facilitating risk-adapted care.

Measuring Knowledge of Community Health Workers at the Last Mile in Liberia: Feasibility and Results of Clinical Vignette Assessments.

INTRODUCTION: Community health workers (CHWs) can provide lifesaving treatment for children in remote areas, but high-quality care is essential for effective delivery. Measuring the quality of community-based care in remote areas is logistically challenging. Clinical vignettes have been validated in facility settings as a proxy for competency. We assessed feasibility and effectiveness of clinical vignettes to measure CHW knowledge of integrated community case management (iCCM) in Liberia's national CHW program. METHODS: We developed 3 vignettes to measure knowledge of iCCM illnesses (malaria, diarrhea, and pneumonia) in 4 main areas: assessment, diagnosis, treatment, and caregiver instructions. Trained nurse supervisors administered the vignettes to CHWs in 3 counties in rural Liberia as part of routine program supervision between January and May 2019, collected data on CHW knowledge using a standardized checklist tool, and provided feedback and coaching to CHWs in real time after vignette administration. Proportions of vignettes correctly managed, including illness classification, treatment, and referral where necessary, were calculated. We assessed feasibility, defined as the ability of clinical supervisors to administer the vignettes integrated into their routine activities once per year for each CHW, and effectiveness, defined as the ability of the vignettes to measure the primary outcomes of CHW knowledge of diagnosis and treatment including referrals. RESULTS: We were able to integrate this assessment into routine supervision, facilitate real-time coaching, and collect data on iCCM knowledge among 155 CHWs through delivery of 465 vignettes. Diagnosis including severity was correct in 65%-82% of vignettes. CHWs correctly identified danger signs in 44%-50% of vignettes, correctly proposed referral to the facility in 63% of vignettes including danger signs, and chose correct lifesaving treatment in 23%-65% of vignettes. Both diagnosis and lifesaving treatment rates were highest for malaria and lowest for severe pneumonia. CONCLUSION: Administration of vignettes to assess knowledge of correct iCCM case management was feasible and effective in producing results in this setting. Proportions of correct diagnosis and lifesaving treatment varied, with high proportions for uncomplicated disease, but lower for more severe cases, with accurate recognition of danger signs posing a challenge. Future work includes validation of vignettes for use with CHWs through direct observation, strengthening supportive supervision, and program interventions to address identified knowledge gaps.

Thrombin-PAR1 signaling in pancreatic cancer promotes an immunosuppressive microenvironment.

Essentials Elimination of PDAC tumor cell PAR1 increased cytotoxic T cells and reduced tumor macrophages. PAR1KO PDAC cells are preferentially eliminated from growing tumors. Thrombin-PAR1 signaling in PDAC tumor cells drives an immunosuppressive gene signature. Csf2 and Ptgs2 are thrombin-PAR1 downstream immune suppressor genes in PDAC tumor cells. ABSTRACT: Background Pancreatic ductal adenocarcinoma (PDAC) is characterized by a prothrombotic state and a lack of host antitumor immune responsiveness. Linking these two key features, we previously demonstrated that tumor-derived coagulation activity promotes immune evasion. Specifically, thrombin-protease-activated receptor-1 (PAR1) signaling in mouse PDAC cells drives tumor growth by evading cytotoxic CD8a+ cells. Methods Syngeneic mixed cell tumor growth, transcriptional analyses, and functional tests of immunosuppressive response genes were used to identify cellular and molecular immune evasion mechanisms mediated by thrombin-PAR-1 signaling in mouse PDAC tumor cells. Results Elimination of tumor cell PAR1 in syngeneic graft studies increased cytotoxic T lymphocyte (CTL) infiltration and decreased tumor-associated macrophages in the tumor microenvironment. Co-injection of PAR1-expressing and PAR1-knockout (PAR-1KO ) tumor cells into immunocompetent mice resulted in preferential elimination of PAR-1KO cells from developing tumors, suggesting that PAR1-dependent immune evasion is not reliant on CTL exclusion. Transcriptomics analyses revealed no PAR1-dependent changes in the expression of immune checkpoint proteins and no difference in major histocompatibility complex-I cell surface expression. Importantly, thrombin-PAR1 signaling in PDAC cells upregulated genes linked to immunosuppression, including Csf2 and Ptgs2. Functional analyses confirmed that both Csf2 and Ptgs2 are critical for PDAC syngeneic graft tumor growth and overexpression of each factor partially restored tumor growth of PAR1KO cells in immunocompetent mice. Conclusions Our results provide novel insight into the mechanisms of a previously unrecognized pathway coupling coagulation to PDAC immune evasion by identifying PAR1-dependent changes in the tumor microenvironment, a PAR1-driven immunosuppressive gene signature, and Csf2 and Ptgs2 as critical PAR1 downstream targets.

A Community Health Worker Intervention to Increase Childhood Disease Treatment Coverage in Rural Liberia: A Controlled Before-and-After Evaluation.

OBJECTIVES: To assess a community health worker (CHW) program's impact on childhood illness treatment in rural Liberia. METHODS: We deployed CHWs in half of Rivercess County in August 2015 with the other half constituting a comparison group until July 2016. All CHWs were provided cash incentives, supply chain support, and monthly clinical supervision. We conducted stratified cluster-sample population-based surveys at baseline (March-April 2015) and follow-up (April-June 2016) and performed a difference-in-differences analysis, adjusted by inverse probability of treatment weighting, to assess changes in treatment of fever, diarrhea, and acute respiratory infection by a qualified provider. RESULTS: We estimated a childhood treatment difference-in-differences of 56.4 percentage points (95% confidence interval [CI] = 36.4, 76.3). At follow-up, CHWs provided 57.6% (95% CI = 42.8, 71.2) of treatment in the intervention group. The difference-in-differences diarrhea oral rehydration therapy was 22.4 percentage points (95% CI = -0.7, 45.5). CONCLUSIONS: Implementation of a CHW program in Rivercess County, Liberia, was associated with large, statistically significant improvements treatment by a qualified provider; however, improvements in correct diarrhea treatment were lower than improvements in coverage. Findings from this study offer support for expansion of Liberia's new National Community Health Assistant Program.

Willingness to Pay for a Maternity Waiting Home Stay in Zambia.

INTRODUCTION: Complications of pregnancy and childbirth can pose serious risks to the health of women, especially in resource-poor settings. Zambia has been implementing a program to improve access to emergency obstetric and neonatal care, including expansion of maternity waiting homes-residential facilities located near a qualified medical facility where a pregnant woman can wait to give birth. Yet it is unclear how much support communities and women would be willing to provide to help fund the homes and increase sustainability. METHODS: We conducted a mixed-methods study to estimate willingness to pay for maternity waiting home services based on a survey of 167 women, men, and community elders. We also collected qualitative data from 16 focus group discussions to help interpret our findings in context. RESULTS: The maximum willingness to pay was 5.0 Zambian kwacha or $0.92 US dollars per night of stay. Focus group discussions showed that willingness to pay is dependent on higher quality of services such as food service and suggested that the pricing policy (by stay or by night) could influence affordability and use. DISCUSSION: While Zambians seem to value and be willing to contribute a modest amount for maternity waiting home services, planners must still address potential barriers that may prevent women from staying at the shelters. These include cash availability and affordability for the poorest households.

Analysis of Prehospital Transport Use for Trauma Patients in Lusaka, Zambia.

Despite an increasing burden of injuries, prehospital transport systems remain underdeveloped in many low- and middle-income countries. Little information exists on the use of prehospital services for trauma patients in Zambia. METHOD: A prospective, observational study of trauma presentations was undertaken for 6 months in Lusaka, Zambia, to establish the epidemiology and outcomes of injury in the region. In addition to demographics and mechanism of injury, data were collected on prehospital transport as well as inpatient resources utilization. Trained study personnel gathered data on trauma presentations 24 h a day. Statistical analysis was conducted using SAS 9.3 from a Microsoft® Access database. RESULTS: 3498 trauma patients were enrolled in the study on arrival to University Teaching Hospital (UTH). 3264 patients had a transport means recorded (95.3 %). Two-thirds (66 %) arrived within 6 h of injury, and 23 % arrived within the first hour after injury. A majority arrived by private vehicle (53.4 %) or public transport (37.7 %); only 5.9 % were transported by public or private ambulance. Of those arriving within the first hour after injury, 69.1 % came by private car, 24.6 % by public transport and 3.1 % by ambulance. There was a small statistical increase in Kampala Trauma Score II among ambulance arrivals. CONCLUSION: Trauma patient use a variety of transport methods to get to UTH. A majority of patients use no formal ambulance transport. Despite this fact, a majority arrives within 6 h of injury but receive no formal prehospital care. An integrated, multilayered prehospital care and transport system may be the most effective approach for Zambia.