Citations

Abstract Rationale Pneumocystis pneumonia (PJP) remains a major opportunistic infection in immunocompromised hosts, with limited therapeutic options. Previous studies identified a conserved cysteine residue (C353) in Pneumocystisphosphoglucomutase (PGM), analogous to that found in other pathogenic fungi but absent in mammalian PGMs, suggesting an exploitable antifungal target. We aimed to define the functional significance and therapeutic potential of targeting Pneumocystis PGM. Methods Full-length P. jirovecii and P. murina PGM cDNAs were cloned into S. cerevisiae pgm2Δ yeast (deficient in PGM activity) using the pYES2.1 TOPO vector for heterologous expression. Recombinant yeast lysates were tested for PGM activity in the presence of the thiol-reactive inhibitor ISFP10 (0-200 μM). Parallel assays were performed using recombinant human PGM lacking C353. Yeast growth inhibition in these strains in the presence of ISFP10 was also measured over 72 hours. For in vitro and ex vivo assays, P. murina organisms were treated with ISFP10, and viability was quantified via qPCR of the mitochondrial 16S ribosomal copy number. Precision-cut lung slice (PCLS) ex vivo cultures from a murine PCP model and in vivo CD4-depleted mice were used to assess ISFP10 efficacy and toxicity. Results Both P. jirovecii and P. murina PGMs showed potent, dose-dependent inhibition of enzymatic activity by ISFP10 up to 12.5 μM, with no inhibition of human PGM at concentrations up to 200 μM. Yeast complementation assays confirmed that ISFP10 significantly reduced the growth of pgm2Δ yeast expressing Pneumocystis spp. PGM. In vitro incubation of P. murina with ISFP10 resulted in significant reductions in organismal 16S mitochondrial copy number, comparable to pentamidine. In ex vivo PCLS models, ISFP10 decreased P. murina burden without affecting uninfected tissue viability. In vivo, ISFP10 administration for seven days significantly reduced fungal burden in CD4-depleted mice with an acceptable safety profile. Conclusions These findings demonstrate that Pneumocystis PGM activity depends on a conserved cysteine residue that is selectively targetable by ISFP10. Pharmacologic inhibition of PGM impairs P. murina viability in vitro, ex vivo, and in vivo with minimal host toxicity. Collectively, these data establish PGM as a promising, fungus-specific antifungal target and support the further development of small-molecule inhibitors targeting Pneumocystis PGM. This abstract is funded by: NIH R01 HL-62150, R21 AI-181542

Abstract Introduction Pneumocystis jirovecii pneumonia (PJP) is a significant opportunistic infection in immunocompromised patients. While cancer patients experience significant immunosuppression that increases their susceptibility to PJP, outcomes of this infection stratified by specific tumor types remain poorly characterized. Methods This retrospective study identified adults with PJP and either solid or hematologic malignancies using the National Inpatient Sample (2016-2022). Exclusion criteria included age <18 years, COVID-19 positivity, concurrent solid and hematologic malignancies, HIV positivity, or missing data. Baseline characteristics were compared between the two cancer groups. Multivariable regression analyses, adjusting for potential confounders, were conducted to estimate adjusted odds ratios for adverse events, treatments, and mortality. All analyses accounted for the complex survey design of the dataset. Results We found 11565 admissions involving PCP matching our selection, with 55.6%(6430) liquid and 44.4%(5135) solid cancers. Both groups contained an elderly population (mean age in solid: 64.25 years, vs. mean age in liquid: 63.36 years, p = 0.139), and mostly males( 51.32% of solid and 66.33% of liquid cancers, p < 0.01). The adjusted Deyo Charlson Comorbidity Index Scores were also comparable(1.65 in solid vs. 1.55 in liquid cancers, p = 0.195). Majority of patients in both groups (73.97% of solid and 72.55% of liquid) were Whites(p = 0.155), insured via Medicare(52.98% of solid and 54.60% of liquid,p=0.580), and hospitalized at urban teaching centers(85.69% of solid and 87.17% of liquid, p = 0.341). Among patients with solid tumors, 32.03% were respiratory/thoracic cancers, 11.88% were breast cancers, 11.10% were gastrointestinal cancers. Among patients with hematologic malignancies, the most common diagnoses were lymphoma (48.4%) followed by leukemia (37.2%). Patients with hematologic malignancies recorded reduced rates of acute respiratory failure, mechanical ventilation requirements, and intubation. In contrast, no significant differences were observed between groups for cardiovascular complications including cardiac arrest and septic shock. Acute kidney injury odds were similarly comparable between the two cohorts(Table 1). Our analysis demonstrated significantly lower mortality in hematologic malignancy patients compared to solid tumor patients, but with longer lengths of stay (15.4 days vs 13.2 days) and higher hospital charges ($234,616 vs $188,792). Conclusions Our findings demonstrate that solid malignancies may pose a bigger threat to PJP outcomes as compared to hematological cancers, warranting further investigation to set up appropriate preventive strategies and treatment protocols. This abstract is funded by: None

Abstract Respiratory viral infections such as influenza and SARS-CoV-2 can lead to the development of chronic lung disease and impaired pulmonary function long after the recovery from acute illness. However, the mechanisms underlying these post-acute sequelae remain poorly understood. Using human lung samples from patients with post-acute sequelae of COVID-19 with pulmonary fibrosis (PASC-PF) and an aged mouse model of chronic lung disease following acute viral infection, we found that CD4+ T cells were enriched near the dysplastic Krt8Hi epithelial regions of the lung. Similarly, in aged mice, CD4+ T cells localized to Krt8Hi areas, and their spatial distribution correlated positively with the extent of epithelial dysplasia. Further analysis of bronchoalveolar lavage (BAL) fluid from COVID-19 convalescent individuals revealed a distinct population of FoxP3−PD-1HiCD4+ T cells highly expressing ICOS, CD69, and CD103 - markers characteristic of both T follicular helper (TFH) and tissue-resident memory (TRM) cells, which we have defined as tissue-resident helper (TRH) cells previously. Notably, the frequency of these TRH-like cells correlated positively with the extent of reticulate or consolidated regions on chest CT scans, indicative of lung fibrosis. Furthermore, the frequency of these cells was negatively associated with lung functional parameters including forced vital capacity (FVC). These findings suggest that PD-1HiCD4+ TRH-like cells expand in PASC and may contribute to chronic lung sequelae. Given that Bcl6 is required for TRH differentiation, we employed an aged, CD4-specific, inducible Bcl6-deficient (Bcl6iΔCD4) mouse model to evaluate the functional contribution of these cells to post viral lung fibrosis. Bcl6 deficiency led to a marked reduction in total and antigen-specific PD-1HiCD4+ TRH cells, as confirmed by flow cytometry and immunofluorescence. Strikingly, Bcl6 iΔCD4 mice displayed significantly decreased inflammatory and fibrotic lesions in the lung compared to wild-type controls. Moreover, Bcl6 iΔCD4 mice exhibited enhanced lung regeneration, evidenced by increased AT1 and AT2 epithelial cells and improved pulmonary function. Together, these findings identify Bcl6-dependent CD4+ TRH responses as key drivers of post-viral chronic lung sequelae. This study reveals a novel immunopathogenic mechanism linking persistent tissue helper memory T-cell responses to impaired lung repair and fibrosis, providing new insight into the development of post-viral lung disease and potential therapeutic targets for conditions such as respiratory long COVID. This abstract is funded by: American Lung Association, NIH

Abstract When evaluating malignant anterior mediastinal masses, thymic carcinoma and lymphoma represent the most common etiologies. We present a case of a patient with an incidentally found anterior mediastinal mass, initially suspected to be thymic carcinoma, who was ultimately diagnosed with primary mediastinal classical Hodgkin lymphoma. A 55-year-old woman with no contributory past medical history presented to her primary care provider with several weeks of cough which was unresponsive to antibiotics and corticosteroids. A chest x-ray demonstrated a large mediastinal mass and subsequent CT chest further revealed an anterior mediastinal mass measuring 15 x 6 x 13 cm. A PET-CT showed intense FDG uptake in the mediastinal mass (SUVmax 14.5) and FDG-avid right pleural lesions suggestive of metastases (SUVmax 4.5). She was referred to outpatient pulmonary clinic. Given imaging findings, thymic carcinoma was initially favored. Following multidisciplinary discussion with Thoracic Surgery, neoadjuvant chemotherapy was recommended prior to any consideration of surgical resection given the size and involvement of mediastinal structures. Thus, CT-guided biopsy was pursued to confirm the diagnosis, but unexpectedly revealed classical Hodgkin lymphoma of the nodular sclerosis subtype. She was diagnosed with stage IVA disease and urgently initiated chemotherapy with nivolumab, doxorubicin, vinblastine, and dacarbazine (N-AVD). A repeat PET-CT two months after initiation of treatment demonstrated marked metabolic and anatomic response, with the mediastinal mass reduced to 8.9 x 5.4 cm with an SUVmax of 2.1. Similarly, the FDG-avid pleural metastases had a decrease in SUVmax to 1.0. The patient was continued on the same treatment regimen. Although thymic carcinoma was initially suspected, a biopsy was obtained because surgical resection was not planned as the initial step in management. Typically, thymic malignancies are not biopsied prior to surgery due to the risk of tumor seeding and the preference for definitive resection, with some exceptions. In this case, the decision to biopsy resulted in the unexpected diagnosis of primary mediastinal classical Hodgkin lymphoma, a particularly rare entity among anterior mediastinal masses. This case underscores the importance of individualized diagnostic strategies and the role of tissue confirmation when clinical or therapeutic circumstances deviate from standard practices. This abstract is funded by: None

Abstract Rationale Rural populations in the US experience a higher lung cancer burden compared to urban residents, potentially due to differences in risk factors and access to preventative care and early detection. We sought to characterize tobacco use, smoking cessation, and lung cancer screening patterns by rurality to identify modifiable gaps in the lung cancer care continuum. Methods We analyzed data from current and former smoking adults in the Southern Community Cohort Study, a large prospective cohort recruited from community health centers across 12 southeastern states. Participants aged 65-80 years with at least 9 months of Medicare Part A/B and less than 3 months of Part C coverage between 2014 and 2020 were included. Data were linked with the National Death Index and Medicare claims for outcome ascertainment. Rurality was defined using Rural-Urban Commuting Area (RUCA) codes. We compared demographic characteristics, smoking patterns, use of smoking cessation interventions, and receipt of low-dose computed tomography (LDCT) screening between rural and urban participants over time. Results Among 10,114 adults included (56% urban; 46% rural), 54% were female, 55% identified as Black/African American, about a third reported less than a high school education, and 45% lived in areas in the highest quartile of deprivation. Urban residents were of similar age (66 vs 67 years), and more likely to currently smoke (42% vs 35%), but had fewer baseline smoking pack-years (27 vs 30 pack-years) than rural residents. Approximately 2% died of lung cancer during follow-up. Using the USPSTF 2013 lung cancer screening criteria, 27% of urban and 26% of rural residents were eligible. This increased unevenly to 38% urban and 35% rural under the USPSTF 2021 criteria. LDCT uptake was low, increasing from 0% in 2014 to 6% in 2020 among screening-eligible participants. Use of cessation interventions was similarly low. Among current smoking participants, 7% received smoking cessation counseling, and 3% had a varenicline prescription. These patterns remained relatively stable over time, with no significant rural-urban differences in LDCT and cessation intervention use. Conclusion Despite modest differences in smoking prevalence and screening eligibility, we found comparable lung cancer mortality and similarly low utilization of LDCT and cessation interventions among rural and urban residents. Our findings suggest that, among people in lower socioeconomic groups, shared socioeconomic constraints may extend beyond the rural-urban divide. Further research is needed to understand how social determinants of health may be addressed to improve lung cancer outcomes across the screening continuum. This abstract is funded by: NIH

Abstract Introduction Solid tumors modify local angiogenesis and co-opt surrounding vasculature to maintain energy supply required for ongoing growth. This process is often complicated by metastasis and hemorrhage. Pulmonary tumors can rarely create intrapulmonary shunt physiology and hypoxemia in this manner; this has been described most often in bronchoalveolar carcinoma. We present a case of malignant intrapulmonary shunt occurring with spindle cell sarcoma, which resolved with arterial embolization. Case Presentation A 72-year-old male with a history of stage IV spindle cell sarcoma with abdominal, vertebral, and pulmonary metastases presented to an outpatient appointment with three weeks of fatigue and decreased exercise tolerance. He had no history of parenchymal lung disease nor any home oxygen requirement. In clinic, he was found to require 6L per minute of supplemental oxygen to maintain saturation of 88%. He was directly admitted to the oncology service. Initial laboratory evaluation was unremarkable. CT imaging demonstrated normal lung parenchyma, no pulmonary embolism, and an 11cm vascular tumor involving proximal branches of the local pulmonary artery (Figure). Transthoracic echocardiography (TTE) with agitated saline revealed a large intrapulmonary shunt. As the patient had limited response to oxygen therapy, this intra-tumoral shunt was deemed the most likely cause of his hypoxemia. Surgical resection was considered but was deemed to confer limited clinical benefit in the setting of multiple metastases. Embolization of the local pulmonary artery was therefore pursued with Interventional Radiology. The patient tolerated the procedure well with complete resolution of hypoxemia post-procedure. His energy and mobility improved, and he was discharged home. Three months later, he continued to require no supplemental oxygen. Discussion While shunt physiology is commonly part of the differential for hypoxemia, it is rarely described as an oncologic complication. This appears to be the first report of such pathology in a sarcoma patient, and the first to report shunt resolution through arterial embolization rather than surgical resection or systemic anti-tumor therapy. In addition, previous cases typically describe shunt detection via selective pulmonary arterial occlusion by Swan-Ganz catheter, whereas here the noninvasive TTE with agitated saline was sufficient. While the few existing reports highlight good response to lobectomy or pneumonectomy, this case highlights the potential for minimally invasive vascular intervention. Despite the metastatic nature of this patient’s disease, he received significant, rapid physiologic and functional benefit from a procedure with less morbidity. Maintaining suspicion of intra-tumoral shunt physiology is appropriate for patients with vascular pulmonary masses and hypoxemia. This abstract is funded by: None

Abstract Introduction Minimally invasive surgical techniques including Robotic-Assisted thoracoscopic surgery (RATS) have advanced the treatment of lung cancer and enhanced patient outcomes from early recovery to improved quality of life. The “July effect” hypothesizes that morbidity and mortality outcomes worsen during the beginning of academic year when new residents and fellows begin training. We investigated the impact of the same on outcomes of RATS among lung cancer patients. Methods Using the National Inpatient Sample (2016-2019), we identified adults(ages≥18 years) with lung cancer who underwent RATS(lobectomy/sublobar resection) at urban teaching centers(UTC). Patients were stratified by surgical timing: July-September versus other months. Multivariable logistic regression compared perioperative outcomes between groups, adjusting for confounders. Results We analyzed 25,480 RATS procedures, with 25.59% performed during July-September. Baseline characteristics were comparable between groups regarding sex, race (White, Hispanic), insurance type, comorbidity burden, and age; however, fewer Black patients underwent surgery during July-September (Table 1a). Multivariable logistic regression revealed no significant differences in perioperative outcomes between the July-September and other months of the year. Evaluated outcomes included thoracic complications like pneumonia (aOR 0.89, 95% CI 0.62-1.28, p = 0.526), pneumothorax (aOR 1.07, 95% CI 0.85-1.34, p = 0.583), air leak (aOR 0.98, 95% CI 0.79- 1.22, p = 0.873), respiratory failure (aOR 0.9, 95% CI 0.50-1.63, p = 0.729) , atelectasis (aOR 1.12, 95% CI 0.88-1.42, p = 0.372), thromboembolic events like pulmonary embolism (aOR 0.63, 95% CI 0.13-2.97, p = 0.557), deep venous thrombosis (aOR 1.01, 95% CI 0.65-1.57, p = 0.952), bleeding complications like transfusion (aOR 0.95, 95% CI 0.55-1.64, p = 0.866), hemothorax/hemoperitoneum/hematoma (aOR 0.58, 95% CI 0.22-1.52, p = 0.264), renal complications (aOR 1.00, 95% CI 0.32-3.17, p = 0.994), conversion to open surgery (aOR 0.53, 95% CI 0.11-2.47, p = 0.417), extended length of stay (>7 days) (aOR 0.96, 95% CI 0.78-1.17, p = 0.667), and in-hospital mortality (aOR 0.57, 95% CI 0.21-1.50, p = 0.250)(Table 1b). Conclusions Our study suggested no “July effect” in the perioperative outcomes of RATS. This demonstrates the robust hospital support systems ensuring the safe transition of resident classes without affecting the patient care negatively. This abstract is funded by: None

Abstract Plasmacytomas are a form of plasma cell malignancy which can occur as isolated lesions or as part of systemic multiple myeloma. We present a case of a patient whose evaluation for an incidentally found lung mass led to the diagnosis of multiple myeloma. A 65-year-old man with no remarkable past medical history presented to the emergency department with two days of fever, cough, and chills. A chest x-ray demonstrated findings suggestive of pneumonia as well as a “smoothly marginated density in the left lung apex.” CT chest further revealed a destructive mass involving the left third rib measuring 7.6 x 4.6 cm; it was difficult to determine from imaging if the mass originated from the lung, pleura, or bone. PET-CT showed significant FDG avidity of the mass (SUVmax 40.2) and FDG-avid left mediastinal and supraclavicular lymph nodes. He subsequently presented to outpatient pulmonary clinic for further evaluation. Given imaging findings, primary lung malignancy or soft tissue sarcoma was initially suspected. He underwent CT-guided biopsy of the mass with pathology showing a kappa light chain-restricted plasmacytoma. Serum studies demonstrated a markedly elevated kappa/lambda ratio of 132. Bone marrow biopsy confirmed a kappa light chain-restricted plasma cell myeloma with 20% plasma cells. On review of previous labs, the patient was noted to have anemia (hemoglobin 11.9 g/dL) previously attributed to iron deficiency anemia as well as hypercalcemia (10.3 mg/dL). Renal function was normal. He was diagnosed with multiple myeloma and started on daratumumab, bortezomib, lenalidomide, and dexamethasone (Dara-VRD), with favorable response to treatment. The presence of plasmacytomas is clinically important to recognize in multiple myeloma as they are predictors of poorer outcomes. The site of origin also carries prognostic implications: paraskeletal plasmacytomas arising from bone marrow are associated with better outcomes than extramedullary plasmacytomas which result from hematogenous spread. In one study, paraskeletal plasmacytomas were found to occur in 17.6% of patients with multiple myeloma, with 40% located in the chest; similarly, extramedullary plasmacytomas were associated with the lungs or pleura in 23% of patients. Altogether, this case underscores the importance of considering plasmacytomas in the differential of a lung mass, particularly if there is osseous involvement. This abstract is funded by: None

Abstract Rationale American Indians and Alaska Native (AI/AN) people have the highest prevalence of tobacco use of any US racial or ethnic minoritized group, though this varies regionally. Smoking, and smoking-related cancers including lung cancer are more common in AI/AN people than non-Hispanic whites in the Pacific Northwest. Lung cancer screening (LCS) is effective but broadly under-utilized in AI/AN eligible adults. This study’s objective was to evaluate a AI/AN community co-designed patient navigation intervention to bridge community healthcare settings to a LDCT-capable LCS program. Methods We conducted a single-arm pilot study of the patient navigation intervention, grounded in community-based participatory research principles. The intervention was formalized in a living handbook, co-created with input from patients and providers at an AI/AN Urban Indian Organization and primary care clinic, Seattle Indian Health Board. Two community health workers served as navigators to deliver culturally sensitive support, link to shared decision-making with a nurse practitioner at the academic LCS program, coordinate transportation, interface with insurance and provide other barrier-directed activities. Patients eligible for LCS (n = 44) were recruited from the AI/AN clinic setting through on-site outreach. Enrolled participants completed pre-navigation surveys which assessed baseline knowledge, attitudes, experiences and barriers. Those who engaged with the central program completed an additional post-navigation survey (n = 15). Electronic health records were reviewed for all navigation and LCS-related data. Results Between July 2023 - November 2024, 44 participants were enrolled in the study. The median age of the participants was 65 (IQR 58-70), 66% reported current smoking, and 76% reported an annual household income <$30,000. All participants reported at least one barrier that delayed care in the past 12 months. On review, two participants were up-to-date on LCS prior to enrollment. Within 6 months, 13 participants completed a shared decision-making appointment and 11 went forward with LDCT. On post-intervention surveys, barriers most commonly addressed were: scheduling (100%), transportation (80%), explaining LCS (80%) and cost/insurance (73%). Participants reported high acceptability, measured by Acceptability of Intervention Measure (AIM median 5.0, IQR 5-5) and patient satisfaction measured by Patient Navigation Satisfaction Measured-Instrument (PNS-I median 45, IQR 42-45). Conclusion A culturally tailored patient navigation program for LCS was feasible and highly acceptable among urban AI/AN adults. Navigation addressed multiple barriers and successfully connected some patient participants from a community clinic to tertiary screening centers for shared decision-making and/or screening. These findings support the effectiveness of academic-community partnered navigation to increase LCS uptake in AI/AN clinic settings. This abstract is funded by: ATS/ALA/Chest Foundation: Respiratory Health Equity Research Award (Triplette)

Abstract Background Despite the reported benefits, lung cancer screening (LCS) uptake remains alarmingly low in comparison to other cancer screening programs. Objective To develop and evaluate an automated, electronic health record (EHR)-embedded LCS outreach program designed to increase screening uptake while minimizing workload for referring providers and schedulers. Methods We developed an automated outreach and referral program at two Mayo Clinic campuses (Rochester [RST] and northwest Wisconsin [NWW]) coupled with a streamlined virtual care delivery process. Eligible patients were identified based on the information in the EHR regarding US Preventive Services Task Force guidelines for screening and were contacted through either a patient portal message, letter, or both. Outreach included LCS educational materials and self-scheduling instructions for a telephone or video shared decision-making (SDM) visit. During the visit, a licensed care team member discussed the risks and benefits of a low dose computed tomography (LDCT) scan with patients who could choose to enroll in the Lung Cancer Screening Program or decline. Results During the study period, 8,845 eligible patients (RST: 2201, NWW: 6644) were contacted using automated portal messages, letters, or both. Among the RST cohort, 2,156 portal messages and 1,060 letters were distributed in comparison to 7,642 portal messages, 6,441 letters, and 618 text messages in the NWWI cohort. The study showed increase in shared decision-making visits completion and screenings for eligible patients across both groups. Portal engagement was higher among the RST group 75.4% than 55.8% in the NWWI group, as was digital brochure access (14.1% vs 6.5%). Scheduling for share-decision-making visits was noted to be higher among the RST group (22% vs 13.6%), though visit completion rates were similar across sites (12.6 vs 13.6%). A lower opt-out rate was noted among the RST group (12.6% vs. 14.3%). Collectively, both campuses demonstrated meaningful patient engagement. Conclusion The automated outreach program effectively increased lung cancer screening engagement and uptake for eligible patients without adding significant administrative burden on primary care providers and clinical staff. Observed differences in engagement between sites, as well as relatively low completion rates highlight the need for further investigation into contextual and operational factors influencing program performance. This abstract is funded by: none