Abstract Introduction Pulmonary artery masses have a broad differential. CT may offer initial characterization, but cardiac MRI and PET/CT provide more definitive information. Histopathologic evaluation is often required. We present a rare case of a pulmonary artery mass with an elevated IgG4 index, initially misclassified as more common benign and malignant entities. Case-Presentation: A 61-year-old never smoking female was referred to the pulmonary clinic for abnormal imaging. Her history was only for patent ductus arteriosus repair in infancy. She initially presented with pleuritic chest pain and was found to have near occlusive mass in the distal main pulmonary artery extending into the proximal left main pulmonary artery. This was presumed to be pulmonary embolism, and anticoagulation was started. At presentation, she reported mild dyspnea and improving chest pain, without constitutional symptoms. Cardiac MRI revealed restricted diffusion and enhancement consistent with pulmonary artery sarcoma. PET-CT revealed FDG avid pulmonary artery mass (SUV max 14.5) without other hypermetabolic lesions. She subsequently underwent resection of the main and proximal left PA mass resection with bovine pericardial reconstruction. Histopathology showed a dense lymphoplasmacytic infiltrate with prominent plasma cell infiltration, IgG4/IgG ratio of 40%, and > 10 IgG4 positive plasma cells per high power field. No histiocytic proliferation or evidence of other atypia. Her serum IgG4 level, CRP, ANCA serology, and fungal serology were normal. Discussion Here we present the case of isolated pulmonary artery mass with elevated IgG4 index of greater than 40% without other organ manifestations of IgG4 related disease (IgG4-RD). Cases of IgG4-RD related infiltration with a pulmonary artery mass have been reported, yet these typically present with other systemic manifestations, vascular inflammation, luminal stenosis, and/or pulmonary hypertension. Based on ACR 2019 IgG4 related disease classification criteria, these patients would not strictly meet criteria for IgG4 related disease. After extensive multidisciplinary discussion, we have elected to hold systemic treatment for IgG4-RD. She will be followed closely, monitoring new evidence of organ infiltration that would warrant systemic treatment. Conclusion Pulmonary artery masses should raise suspicion for various benign etiologies, such as chronic thromboembolism, and malignant entities, including pulmonary artery sarcoma. Cardiac MRI, PET/CT, and histopathology were critical in this patient’s evaluation. IgG4-related disease can rarely present as an intimal pulmonary artery mass. However, this is typically accompanied by systemic findings suggestive of IgG4-RD, other vascular infiltration, and/or pulmonary hypertension, all of which were absent in this patient. This abstract is funded by: None
D21-17 Dysregulation of Prostaglandin E2 Pathways Correlate With Asthma Severity
Abstract Background Prostaglandin E2 (PGE2) exerts paradoxical effects in asthma, acting as both a protective mediator and a contributor to pathology depending on context. Its role is shaped by type 2 (T2)-status, eosinophilia, and exacerbation frequency. In epithelial cell cultures from asthmatic and healthy individuals, interleukin (IL)-13 suppresses PGE2 synthesis genes (PTGS2 and PGES) while upregulating HPGD, which encodes for the PGE2 catabolic enzyme 15-prostaglandin dehydrogenase (15-PGDH) (PMID:16751012), suggesting diminished PGE2 availability during T2 inflammation. Similarly, in aspirin-exacerbated respiratory disease (AERD), impaired cyclooxygenase disrupts PGE2 biosynthesis, fueling unchecked leukotriene production and eosinophilic inflammation (PMID: 30516547), underscoring PGE2’s protective role in limiting disease progression. Conversely, in nasal polyps, tuft cells are activated by IL-13 to produce PGE2 (PMID: 35608904), highlighting PGE2’s potential pathogenicity. Objective To assess associations between PGE2-pathway gene expression in bronchial brushings and asthma severity, and to determine how nasal polyp history modifies these relationships. Methods We analyzed bronchial epithelial brushings from 109 adults with asthma (mean age 42.4±12.1, 64% female, 52% severe asthma, 18% nasal polyps) using normalized and batch-corrected RNA-seq data from the baseline visit in the Severe Asthma Research Program (SARP)3 (PMID: 36796454). Age-adjusted and nasal polyp-adjusted relationships were calculated between ratios of PGE2 synthesis and metabolism genes and clinical outcomes (ASSESS score, FEV1 %predicted). The composite PGE2 score (PMID: 35608904), derived from nasal polyp analysis, was calculated from the average scaled log-normalized expression of six PGE2-responsive genes. All data were analyzed using a linear regression mixed model with a random effect for site. Results Ratios of PGE2 synthesis genes (PTGS1/2, PTGES2) to HPGD were significantly associated with greater disease severity (change in ASSESS Score) (Fig.1A, solid lines) and lower lung function (change in FEV1 %predicted) (Fig.1B, solid lines). These relationships persisted after adjusting for nasal polyps (Fig.1, dashed lines). The composite PGE2 score was also related to disease severity (Fig.1A, black solid line) but attenuated when nasal polyps were accounted for (Fig.1A, black dashed lines). Interestingly, lower lung function remained associated with the PGE2 score even after nasal polyp adjustment (Fig.1B, dashed black lines). Conclusions Our analysis demonstrates that the balance between PGE2 synthesis and degradation in the bronchial epithelium is closely linked to asthma severity and lung function, independent of nasal polyp status. Future work will integrate transcriptomic and clinical data longitudinally to establish whether PGE2 could serve as a biomarker for asthma trajectory. This abstract is funded by: HL115118 (LCD), U10HL109152 (S.E.W.), U10HL109172 (to E.I. and B.D.L), U10HL109168 (N.N.J.), U10HL109250 (S.C.E), U10HL109164 (W.C.M), U10HL109257 (M.C), and U10HL109146 (to P.G.W. and S.A.C.)
D21-16 Muc1, Muc4 and Ceacam5 Expression Are Elevated in Severe Asthma and Correlate With the Degree of Obstruction and Prospective Exacerbations
Abstract Rationale Type-1 inflammation in asthma leads to significant airway level changes independent of Type-2 inflammation and may underlie the severity seen in combined Type1/2 high disease. As IFNs can cause airway epithelial injury and impaired repair, we applied a novel interpretable machine learning algorithm, SLIDE, to analyze the transcriptome of airway epithelial brushings of mild-moderate (MMA) and severe asthma (SA) participants in the Immune Mechanisms in Severe Asthma (IMSA) cohort to identify latent/hidden factors of disease that associate with disease severity. Methods The expression of genes identified by SLIDE as part of a co-expression program was assessed in the full IMSA cohort by severity and in an independent cohort of the NHLBI Severe Asthma Research Program (SARP). We also examined associations of these genes with clinical asthma outcomes in both cohorts. Results SLIDE identified aberrant increased expression of membrane-tethered mucin genes, MUC1 and MUC4. MUC1 appeared in each of 5 significant latent factors associated with greater severity and MUC4 in 2/5. Standard DGE analysis also identified the gene CEACAM5 as a predictor of severity. Pathway analysis of latent factor genes revealed airway keratinization which may contribute to airway remodeling and worsening obstruction over time. Expression of MUC1, MUC4, and CEACAM5 were increased in SA compared to HC in both the full IMSA and separate SARP cohorts (p < 0.001 for all genes in both cohorts). Expression in MMA was consistently lower than in SA in both cohorts, reaching significance in IMSA (p < 0.01) but not consistently in SARP (MUC1 p = 0.04, MUC4 p = 0.27, CEACAM5 p = 0.27). Protein analysis of endobronchial biopsies by immunofluorescence staining showed a trend towards increased MUC1 protein content with evidence of secretion. MUC1, MUC4 and CEACAM5 were negatively correlated with FEV1 % predicted in both cohorts (IMSA: MUC1 r=-0.47, p < 0.01, MUC4 r=-0.47, p < 0.01, CEACAM5 r=-0.62, p < 0.01; SARP: MUC1 r=-0.19, p = 0.05, MUC4 r=-0.29, p < 0.01, CEACAM5 r=-0.51, p < 0.01). All three genes positively correlated with prospective exacerbations in both cohorts (IMSA: MUC1 r = 0.345, p = 0.01, MUC4 r = 0.216, p = 0.08, CEACAM5 r = 0.368, p < 0.01; SARP: MUC1 r = 0.22, p = 0.02, MUC4 r = 0.32, p < 0.01, CEACAM5 r = 0.38, p < 0.01). Conclusions The expression of MUC1, MUC4 and CEACAM5 increased with asthma severity in the airway epithelium and correlated with both prospective exacerbations and obstruction. As pathway analysis of genes in the significant latent factors were associated with airway keratinization aberrant expression of these mucins (with known signaling functions) may contribute to maladaptive repair and airway remodeling that drives obstruction over time, contributing to worse asthma outcomes. This abstract is funded by: NIH
C70-17 Genetic Variation in the RGS2 Promoter Reduces RGS2 Expression and Induces a Human Airway Smooth Muscle Hypercontractile Phenotype
Abstract Rationale The activity of fucosyltransferase 2 (FUT2) determines if mucin glycan structures in epithelial mucus include histo-blood group antigens (HBGAs). People with active FUT2 express HBGAs in epithelial mucus secretions and are terms “secretors”, while non-secretors lack HBGAs in their secretions because they have a FUT2 genotype that inactivates the glycosyl transferase. Prior research suggests that secretors who are blood type O (type O secretors) are susceptible to asthma exacerbations1 and that FUT2 knockout mice (functional non-secretors) are protected from mucus plugging in allergen challenge models2,3. We set out here to determine if secretor status influences mucus plug prevalence in asthma and to confirm if type O secretors are susceptible to asthma exacerbations. Methods We determined secretor status in asthma participants from the Severe Asthma Research Program-3 (SARP-3) cohort (N = 507) in two ways, a specific fucose lectin binding assay in sputum and FUT2 genotyping. Blood group type was determined using ABO genotyping. We analyzed mucus plug segment scores, asthma exacerbations rates and other clinical and biological features in patients stratified by secretor status and blood type (non-secretors, type O secretors, and non-type O secretors). Results Secretor status determined by lectin binding in sputum was strongly concordant with genotypic analysis. Within the SARP-3 cohort, 26.2% were non-secretors, 32.3% type were O secretors, and 41.4% were non-type O secretors. Mucus plug segment scores, annualized asthma exacerbation rates, and other measures of asthma severity were similar in non-secretors, type O secretors, and non-type O secretors (Table). Although type O secretors had increased values for fractional exhaled nitric oxide (FeNO) and higher expression of type 2 gene network genes in their sputum cells, measures of sputum eosinophil inflammation were not higher in this subgroup (Table). Conclusion Secretor status does not influence the prevalence of mucus plugging in asthma patients, and we did not confirm a prior report that type O secretors have an increased risk of asthma exacerbation. Although type O secretors have modestly increased FeNO levels and increased expression of type 2 immune genes in their sputum, it is not clear if this is a biologically important signal. 1. Innes et al. AJRCCM; 2011. 2. Saku et al. JACI; 2019. 3. Hara et al. AJRCMB; 2025 This abstract is funded by: The study was supported by the National Institutes of Health grants R01 HL080414 (JVF), P01 HL107202 (JVF), R01 HL164787 (JVF), U10 HL109172 (EI), U10 HL109152 (SEW), U10 HL109257 (MC), U10 HL109250 (SCE), U10 HL109146 (JVF), U10 HL109164 (ERB), U01 HL146002 (BDL), U10 HL109086 (DTM) and Sandler Asthma Basic Research Center at UCSF (JVF). The following companies provided financial support for study activities at the Coordinating and Clinical Centers beyond the third year of patient follow-up: AstraZeneca, Boehringer-Ingelheim, Genentech, GlaxoSmithKline, Sanofi–Genzyme Regeneron, and Teva. These companies had no role in study design or data analysis, and the only restriction on the funds was that they be used to support the SARP initiative.
Murine modeling of IDH-mutant 1p/19q-codeleted oligodendroglioma reveals genotype specific phenotypes
Abstract Oligodendroglioma is a primary central nervous system tumor classified by the presence of isocitrate dehydrogenase (IDH) mutations and codeletion of 1p/19q. Here we describe the generation of an IDH-mutant 1p/19q-codeleted oligodendroglioma mouse model using in utero electroporation. We identified IDH1 R132H , PIK3CA E545K , Cic KO , Fubp1 KO and Cdkn2a KO as the optimal combination (termed Oligo Cdkn2a ) to drive fully penetrant tumors that histologically resemble human grade II/III IDH-mutant, 1p/19q-codeleted oligodendroglioma. Replacing Cdkn2a with Trp53 loss in this mouse model shifted tumor histology towards high grade astrocytoma. Oligo Cdkn2a tumors displayed metabolic and transcriptional changes associated with IDH and CIC mutations, and single cell sequencing identified a bias towards oligodendrocyte differentiation compared to an IDH wild-type glioblastoma mouse model. Oligo Cdkn2a tumors represent the first mouse model system to recapitulate the genetic, histological and transcriptional features of human IDH-mutant 1p/19q-codeleted oligodendrogliomas, offering a platform to further dissect tumor biology and test new therapeutic strategies.
C34-10 Inflammatory Genes Are Downregulated in Induced Sputum of Corticosteroid Responders but Unchanged in Non-Responders
Abstract Rationale We hypothesize that corticosteroid resistance causes uncontrolled inflammation and severe asthma. The genetic and molecular mechanisms underlying steroid responsiveness in asthma remain poorly understood (PMID28493293). This study aims to characterize transcriptomic profiles distinguishing steroid responders from steroid resistant asthma. Methods Longitudinal bulk RNA-seq of SARP3 sputum samples was analyzed before and after an “induced phenotype” with 40 mg triamcinolone acetonide (TCA) injection (PMID 27967215). Participants were classified as responders or non-responders based on whether their FEV₁ change after TCA exceeded the median. Paired differential gene expression analyses were performed separately for each group using limma and voom, with participant as a factor and adjustment for sputum cell count differentials. Z-scores were calculated to compare gene expression changes after TCA injection between responders and non-responders, and pathway enrichment was assessed using the fgsea package. Results Baseline demographics and clinical characteristics of 696 SARP3 asthma participants receiving TCA are shown in Table 1. The median [IQR] FEV1 change post-TCA was 1.81% [-2.16, 7.17]. Responders had higher baseline FEV1%, FEV1/FVC ratio, blood eosinophil counts, and sputum eosinophil percentages, but lower serum CRP levels. Steroid responsiveness was associated with asthma severity (Table 1). Among 154 participants with paired sputum RNA-seq data, 70 (45%) exhibited >1.81% improvement in FEV₁ and were classified as responders. Following TCA treatment, non-responders showed no significant changes in gene expression. In responders, 18 genes were upregulated and 203 downregulated. Downregulated genes were associated with Th2 immunity (IL13, IL1RL1, CCL17, SIGLEC8), IgE signaling (FCER1A, FCER2), epithelial barrier function and mucus production (MUC2, MUC7, ALOX15, TFF3), tissue remodeling and fibrosis (MMP10, TIMP3), ciliary function (DNAH5, CFAP43, FOXJ1), and airway hyperreactivity (HRH4, RAMP1). Key genes notably downregulated in responders compared to non-responders included IL13, CCL5, PTGDR2, FCER2, and CLEC10A. Pathway analysis revealed enhanced IL-10-mediated anti-inflammatory signaling, suppression of pro-inflammatory pathways (NF-κB, IL-1, Th1/Th2, asthma, arachidonic acid metabolism, chemokine, NOTCH4), and regulation of mitochondrial oxidative phosphorylation. Conclusions Steroid resistance impairs glucocorticoid-mediated suppression of pro-inflammatory pathways, including NF-κB, IL-1, and Th1/Th2 signaling. This persistent airway inflammation limits improvements in lung function and contributes to worse clinical outcomes, including increased airflow obstruction, and symptom burden. Glucocorticoid resistance in asthma may be driven by receptor dysfunction, airway inflammation, epigenetic changes, and environmental exposures resulting in persistent airway inflammation and remodeling. Elucidating the molecular mechanisms underlying steroid resistance is critical for developing personalized targeted therapies in asthma. This abstract is funded by: NIH-NHLBI - R01 HL161674 (PI: Joe Zein)
C34-11 Sex May Modulate the Association Between Dnah11 Primary Ciliary Dyskinesia Risk Variants and Asthma
Abstract Rationale Primary ciliary dyskinesia (PCD) pathogenic gene variants disrupt motile cilia, leading to both PCD and asthma through epithelial dysfunction. Asthma shows sex differences, and progesterone regulates ciliary beat frequency, indicating that genetic defects in ciliary proteins may exert sex-dependent effects. Therefore, we hypothesize that rare, pathogenic variants in PCD genes contribute to asthma risk in a sex-specific manner. Methods We performed a rare-variant aggregation analysis of the DNAH11 gene using UK Biobank OQFE exome dosages, with sex-stratified analyses. Within each sex, genotype dosages were coded as individual-level minor allele counts (0-2) and filtered to include variants with a minor allele frequency (MAF) ≤1% and a minor allele count (MAC) ≥5 across the cohort. Asthma phenotypes were defined from a curated dataset (N = 452,927), excluding COPD and other lung diseases. For each sex, logistic null models adjusted for age were fitted, and gene-level associations for binary outcomes were tested using SKAT, Burden, and SKAT-O. To assess variant-specific influences, we performed leave-one-out (LOO) analyses, sequentially omitting each variant and recalculating p-values. The effect size across the cohort was calculated by fitting a Firth logistic regression comparing carriers to non-carriers, adjusted for age by sex. Finally, sex modification was tested using a Firth model including carrier-by-sex interaction term. Results After filtering, DNAH11 included two rare variants; 7:21564185-G>T and 7:21591370-G>A in each sex (MAF≈1-2x10-5). Among females (N = 245,718; 28,649 with asthma), 16 carriers were observed (MAC≈16). Gene-based tests showed a significant association with asthma (Burden_p=0.004; SKAT-O_p=0.005; SKAT_p=0.013). Firth carrier model OR was 4.58 (95% CI 1.62-11.98, p = 0.0055) (Figure 1A). LOO analyses (Figure 1B) showed both variants contributed to the signal; removing 7:21591370-G>A increased SKAT-O p to 0.075 (Δ-log10p≈+1.15), while removing 7:21564185-G>T increased p to 0.014 (Δ-log10p≈+0.41, with the association remaining significant after removing the latter. Among males (N = 207,209; 20,777 with asthma), 10 carriers were observed (MAC≈10) with no significant association (Burden_p=0.926; SKAT-O_p=0.797; SKAT_p=0.668; Firth_p=0.781). The carrier-by-sex interaction term in the combined Firth model was not significant (p = 0.190), suggesting the female-specific signal could not be detected in the males due to limited power. Conclusions This analysis provides primary evidence that these rare, pathogenic variants in the DNAH11 PCD gene may contribute to asthma susceptibility in a sex-specific manner, with a significant association observed only in females. The signal was predominantly driven by 7:21591370-G>A. This suggests that genetic disruption of ciliary function may interact with female-specific hormonal factors (i.e., progesterone) to influence asthma risk. This abstract is funded by: NIH
C34-14 The Association of Oxylipins on Asthma Morbidity and Effect Modification by Body Mass Index
Abstract Rationale Asthma and obesity are common comorbidities, both driven by inflammation and oxidative stress. Oxylipins are derivatives of polyunsaturated fatty acids that regulate the onset and resolution of inflammation. Oxylipin profiles are altered in obesity and have been shown to differentiate asthma from non-asthma; however, the association between oxylipins and asthma outcomes and the impact of obesity is not known. This study aims to identify differences in serum oxylipins associated with asthma morbidity and evaluate the effect modification by BMI. Methods We analyzed 150 participants in the Best African American Response to Asthma Drugs (BARD) clinical trial. Ninety oxylipins were quantified using liquid chromatography tandem mass spectroscopy from serum obtained at the time of randomization. Oxylipins found to be above the limit of detection in > 80% of samples were log-transformed and included in the analysis. Asthma severity measures included past 12-month systemic corticosteroid use for asthma exacerbation, spirometry, asthma control and asthma quality of life questionnaires (AQLQ). The associations between oxylipins and asthma outcomes were tested using multivariable regression models adjusted for sex, age, BMI, absolute eosinophil count, percent African ancestry, and child vs adult/adolescent cohort. A false discovery rate (FDR) of < 0.1 is used to determine statistical significance. Results Of the 90 oxylipins measured, 42 (46.7%) were detected in > 80% of all samples and included in the analysis. In multivariable models, the pro-inflammatory arachidonic acid (AA) derivative 5,6-DiHETrE was associated with decreased odds of past 12-month systemic corticosteroid use (FDR-adjusted p-value 0.0628). AA derivatives TXB2, PGF2a, and 6-α-prostaglandin were associated with increased FEV1/FVC (FDR-adjusted p-values=0.0925). Thirteen oxylipins were associated with decreased asthma-related quality of life in multivariable models, including AA metabolites 5S-HETE, 5-KETE, 14,15-EET, LTB4, and Lipoxin A4; dihomo-gamma-linoleic acid metabolites 5-HETrE and 15-HETrE; linoleic acid metabolites 3-OxoODE and 9-OxoODE; and eicosapentaenoic acid metabolites 15-HEPE and 17,18-EpETE, all with FDR-adjusted p-values<0.05. Oxylipin-BMI interaction was significant only in the AQLQ models. In all but LTE4, increased concentrations of oxylipins were associated with a decreased quality of life in individuals with higher BMI (Figure). Six of these oxylipins are products of lipoxygenase activity. Conclusions In this study, we find decreased quality of life with increasing concentrations of pro-inflammatory and resolving oxylipins among those with obesity. These oxylipins are primarily produced via lipoxygenases and may represent an important inflammatory pathway in obesity-associated asthma. Quantification of sputum oxylipins and correlation with serum levels will be important in understanding potential mechanisms and is forthcoming. This abstract is funded by: K12TR004412, R01HL123385, U10HL098075, Parker B. Francis Fellowship, 2L30HL159725
C33-05 Feature Importance Statistics Reveal Gina 2025-aligned Predictors of Asthma Exacerbations in U.S. Adults: A Cross-sectional Machine-learning Study Using Nhanes 2017-2020
Abstract Rationale Asthma exacerbations remain a leading cause of emergency visits and impaired quality of life. The 2025 Global Initiative for Asthma (GINA) report emphasizes early identification of Type 2 inflammation, treatable traits, and comorbidities to prevent attacks. Machine learning (ML) was applied to population level data to uncover complex, nonlinear relationships between biomarkers, lifestyle factors, and exacerbation risk. This study aimed to identify key predictors of asthma exacerbations using explainable ML techniques and to interpret these predictors through the lens of GINA 2025 guidelines. Methods A cross-sectional analysis was performed using the National Health and Nutrition Examination Surveys (NHANES) 2017-2020. Adults aged ≥18 years with available asthma history and laboratory data (n = 7,922) were included. The outcome was self-reported asthma exacerbation within the past 12 months. Univariable logistic regression was used to preselect covariates from 680 demographic, dietary, laboratory, and anthropometric variables using a significance threshold of p < 0.0001. Selected covariates were then entered into an XGBoost classifier. Model discrimination was assessed by the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Feature importance was ranked by the Gain metric, and Shapley Additive Explanations (SHAP) were applied to improve interpretability and align results with GINA 2025 clinical domains. Results The final model included 55 covariates and achieved an AUROC of 0.737, sensitivity of 0.960, and NPV of 0.967 for predicting exacerbations. The most influential features were octanoic acid intake, eosinophil percentage, hip circumference, standing height, and high-sensitivity C-reactive protein (hs-CRP). Individuals reporting exacerbations had higher eosinophil percentages (3.36% vs. 2.76%), larger hip circumference (115.2 cm vs. 107.2 cm), and higher hs-CRP (6.08 vs. 4.00 mg/L). These findings correspond to GINA 2025’s emphasis on eosinophils as biomarkers for anti-inflammatory therapy, systemic inflammation as a treatable trait, and obesity as a modifiable risk factor for symptom control and exacerbation prevention. Conclusion Explainable ML applied to NHANES data accurately identified physiologic and inflammatory predictors of asthma exacerbations that mirror the GINA 2025 framework. Eosinophil levels, systemic inflammation, and adiposity emerged as key treatable traits linked to exacerbation risk. These findings demonstrate the utility of ML in translating population-level data into actionable insights consistent with GINA 2025’s strategy for individualized, inflammation-guided asthma management. This abstract is funded by: None