Primary nasal influenza infection rewires tissue-scale memory response dynamics.

The nasal mucosa is often the initial site of respiratory viral infection, replication, and transmission. Understanding how infection shapes tissue-scale primary and memory responses is critical for designing mucosal therapeutics and vaccines. We generated a single-cell RNA-sequencing atlas of the murine nasal mucosa, sampling three regions during primary influenza infection and rechallenge. Compositional analysis revealed restricted infection to the respiratory mucosa with stepwise changes in immune and epithelial cell subsets and states. We identified and characterized a rare subset of Krt13+ nasal immune-interacting floor epithelial (KNIIFE) cells, which concurrently increased with tissue-resident memory T (TRM)-like cells. Proportionality analysis, cell-cell communication inference, and microscopy underscored the CXCL16-CXCR6 axis between KNIIFE and TRM cells. Secondary influenza challenge induced accelerated and coordinated myeloid and lymphoid responses without epithelial proliferation. Together, this atlas serves as a reference for viral infection in the upper respiratory tract and highlights the efficacy of local coordinated memory responses.

Primary nasal viral infection rewires the tissue-scale memory response.

The nasal mucosa is frequently the initial site of respiratory viral infection, replication, and transmission. Recent work has started to clarify the independent responses of epithelial, myeloid, and lymphoid cells to viral infection in the nasal mucosa, but their spatiotemporal coordination and relative contributions remain unclear. Furthermore, understanding whether and how primary infection shapes tissue-scale memory responses to secondary challenge is critical for the rational design of nasal-targeting therapeutics and vaccines. Here, we generated a single-cell RNA-sequencing (scRNA-seq) atlas of the murine nasal mucosa sampling three distinct regions before and during primary and secondary influenza infection. Primary infection was largely restricted to respiratory mucosa and induced stepwise changes in cell type, subset, and state composition over time. Type I Interferon (IFN)-responsive neutrophils appeared 2 days post infection (dpi) and preceded transient IFN-responsive/cycling epithelial cell responses 5 dpi, which coincided with broader antiviral monocyte and NK cell accumulation. By 8 dpi, monocyte-derived macrophages (MDMs) expressing Cxcl9 and Cxcl16 arose alongside effector cytotoxic CD8 and Ifng-expressing CD4 T cells. Following viral clearance (14 dpi), rare, previously undescribed Krt13+ nasal immune-interacting floor epithelial (KNIIFE) cells expressing multiple genes with immune communication potential increased concurrently with tissue-resident memory T (TRM)-like cells and early IgG+/IgA+ plasmablasts. Proportionality analysis coupled with cell-cell communication inference, alongside validation by in situ microscopy, underscored the CXCL16-CXCR6 signaling axis between MDMs and effector CD8 T cells 8dpi and KNIIFE cells and TRM cells 14 dpi. Secondary influenza challenge with a homologous or heterologous strain administered 60 dpi induced an accelerated and coordinated myeloid and lymphoid response without epithelial proliferation, illustrating how tissue-scale memory to natural infection engages both myeloid and lymphoid cells to reduce epithelial regenerative burden. Together, this atlas serves as a reference for viral infection in the upper respiratory tract and highlights the efficacy of local coordinated memory responses upon rechallenge.

Implementation Costs of Technology-Enhanced Transitional Palliative Care for Rural Caregivers.

OBJECTIVES: Compared to urban family caregivers (FCG), rural FCG experience greater burdens accessing coordinated care for their loved ones during and after hospitalization. The impact of technology-enhanced transitional palliative care (TPC) on caregiver outcomes is currently being evaluated in a randomized control trial. This study evaluates resource use and health system costs of this FCG-focused TPC intervention and potential Medicare reimbursement mechanisms. METHODS: Rural caregivers of hospitalized patients were randomized into an 8-week intervention consisting of video visits conducted by a registered nurse certified in palliative care, supplemented with phone calls and texts (n = 215), or attentional control. Labor costs were estimated for a registered nurse and compared to scenario analyses using a nurse practitioner or social worker wages. Medicare reimbursement scenarios included Transitional Care Management (TCM) and Chronic Care Management (CCM) CPT codes. RESULTS: In the base case, TPC cost was $395 per FCG facilitated by a registered nurse, compared to $337 and $585 if facilitated by a social worker or nurse practitioner, respectively. Mean Medicare reimbursement in the TCM-only scenario was $322 and $260 for high or moderate complexity patients, respectively. Reimbursement in the CCM only scenario was $348 and $274 for complex and non-complex patients, respectively. Reimbursement in the TCM+CCM scenario was $496 and $397, for high/complex and moderate/non-complex patients, respectively. CONCLUSION: TPC is a feasible, low cost and sustainable strategy to enhance FCG support in rural areas. Potential reimbursement mechanisms are available to offset the costs to the health system for providing transitional palliative care to caregivers of patients recently hospitalized.