Citations

Abstract Description Innate lymphoid cells (ILCs) play a key role in the mucosal innate immune system, particularly in cytokine production. While studies in mice have shown that ILCs are involved in epithelial barrier maintenance and pathogen protection, their role in human mucosal immunity, especially in the female genital tract (FGT), has yet to be fully explored. Here, we characterized genital ILC subpopulations from human hysterectomy samples (endometrium, endocervix, and ectocervix) using spectral flow cytometry, CITE-seq, and ChipCytometry for spatial analysis, and assessed their response to HIV stimulation. Our results reveal novel compartmentalization of genital ILC subsets, with CD161 and NKp44 following opposite expression patterns that distinguish functional states both at steady-state and in response to HIV. At rest, CD161+ ILC3s were enriched for IL-22, and CD161- ILC1s for IFN-g. In contrast, NKp44 was linked to degranulation and identified ILC3s in lymphoid aggregates in the endometrium. Following HIV stimulation, genital ILCs mounted an antiviral response within 30 minutes via transcriptional changes. CD161 expression predicted cytokine secretion (IFN-g and IL-22) in preloaded ILCs and was downregulated after stimulation, while NKp44 was upregulated. These findings highlight the unique role of human genital ILCs in mucosal protection prior to and following viral stimulation. Funding Sources NIH R01AG060801 (MRG) R21AI172065 (MRG) U01AG084766 (MRG) Burroughs Welcome Fund PATH award (1334236) (MRG) Topic Categories Mucosal and Regional Immunology (MUC)

Background: Fontan circulation is characterized by the absence of a subpulmonary ventricle with resultant systemic venous hypertension. Despite exercise intolerance being nearly universal in this population, the determinants of exercise capacity in this population are still poorly understood. Research Question: We investigated the prevalence of peripheral impairment and assessed the contribution of peripheral O 2 extraction versus central hemodynamics to peak O 2 consumption (pVO 2 ) post-Fontan palliation. Methods: This single-center retrospective cross-sectional study compared 52 consecutive adults post-Fontan procedure who underwent exercise catheterization to patients with heart failure with preserved ejection fraction (HFpEF) and non-cardiac dyspnea (NCD) at 1:1 ratio. Several previously reported measures for peripheral O 2 extraction were evaluated in the absence of a golden standard. Correlates of pVO 2 were identified by multivariate linear regression analyses using the backward selection method. Results: Patients with Fontan circulation were younger [age 32 (24;36) years] and tended to have a lower body mass index [26 (23; 29) kg/m 2 ] compared to patients with HFpEF [70 (57; 75) years, p<0.001 and 33 (27; 39) kg/m 2 , p<0.001] and NCD [48 (38; 61) years, p<0.001 and 27 (24; 35) kg/m 2 , p=0.08]. Peak heart rate [108 (85;126) vs 108 (95;125) bpm] and indexed stroke volume [46 (39;54) vs 45 (40;53) ml/m 2 ] were similar in the Fontan and HFpEF groups but lower compared to NCD [126 (108;141) bpm, p<0.001 and 51 (45;59) ml/m 2 , p<0.001]. Peak mean pulmonary artery pressures were highest in HFpEF [45 (41;50) mmHg, p<0.001], followed by Fontan and NCD [26 (22;31) vs 23 (19;25) mmHg, p=0.03]. Median peak O 2 extraction post-Fontan was comparable to HFpEF [12 (10;14) vs 11 (10;13) ml/dl, p=0.17] but higher than in NCD [10 (9;12) ml/dl, p<0.001]. It was <14 ml/dl in 73% compared to 94% and 98% of patients with HFpEF and NCD [p<0.001]. O 2 extraction ratio was <70% in 62% compared to 60% in HFpEF and 96% in NCD [p<0.001]. Correlates of pVO 2 post-Fontan were peak O 2 extraction [β 0.5±0.1 per ml/dl; p<0.001], mean pulmonary artery pressures [β -0.2±0.05 per mmHg; p=0.002], heart rate [β 0.03±0.01 per bpm; p=0.01], and systolic arterial blood pressure [β 0.03±0.01 per mmHg; p=0.02]. Conclusion: Impaired O 2 extraction is prevalent amongst adults post-Fontan. Whether exercise can modulate this important determinant of exercise capacity post-Fontan merits further investigation.

Abstract Clinical flow cytometry laboratories are facing rising test volumes, greater assay complexity, and increasing requirements for quality control and assay validation. In response, the International Clinical Cytometry Society (ICCS) conducted a workload survey in early 2023 to gather updated information on assay volumes, complexity, staffing, and technology. Data analysis focused on identifying correlations between length of time to introduce new assays and other factors as a means to gain insight about laboratories that seem to be either adapting or struggling. Flow cytometry assays were categorized into 3 levels of technical/interpretative complexity: high (e.g., measurable/minimal residual disease (MRD assays)), moderate (e.g., leukemia/lymphoma assays (Assays L&L ), excluding MRD assays), and low (e.g., CD4 count). Annual assays per staff member were calculated according to staff involved in case sign‐out (Staff Signout ) or other laboratory operations (Staff LabOps ). Respondents were from 101 laboratories in the United States (69.3%), Canada (4.0%), and other countries (26.7%). Low, moderate, and high technical/interpretative complexity assays were performed in 85.1%, 97.0%, and 47.5% of all laboratories, respectively. Median annual total assays (Assays Total ) per laboratory were 3515 and, based on complexity, were 1518.5 (low), 1808.8 (moderate), and 350 (high). Among all laboratories, the median time (interquartile range) to introduce new Assays L&L was 6 mos. (4–12 mos.), to introduce MRD assays was 11 mos. (5–12 mos.), and to validate/go‐live with new cytometers was 8 mos. (4–12 mos.); these times positively correlated with each other. This study confirmed significantly increased workload since the prior ICCS 2013 workload survey with a concurrent decrease in Staff LabOps . Faster introduction of new assays correlated with other successes, including quicker validation of and going live with new cytometers. Among all laboratories, those that performed myeloid MRD assays versus those that did not were also found to be faster to introduce new assays. The need for sufficient staffing has been emphasized because laboratories with both higher annual volumes of myeloma MRD assays and higher ratios of Assays Total per Staff LabOps were slower to introduce new assays. “Lack of staff and/or time dedicated or protected for assay development” and, more generally, “staff number” were the most commonly identified major barriers for new assay development, with the former specifically linked to slower introduction of new assays among all laboratories.

Abstract Objectives Granulomatous myositis (GM) is defined by focal collections of activated macrophages that fuse to form multinucleated cells that aggregate into granulomas within skeletal muscle. This study aimed to elucidate the pathophysiology of GM by defining its specific transcriptomic profile. Methods Bulk RNA sequencing was performed on 722 muscle biopsies, including 38 from patients with GM, other myopathies and healthy comparators. Spatial transcriptomics and immunohistochemistry assays were used to identify the location of specific transcripts and proteins within the tissue. Results We conducted a systematic analysis of the inflammatory pathways implicated in GM. This analysis revealed that GM muscle biopsies are characterized by elevated levels of IFNγ, IFNγ-inducible genes and proinflammatory cytokine genes including IL1B, TNF and TGFB1. Additionally, we identified a specific gene signature in GM, comprising 1293 genes that were significantly upregulated and 256 significantly downregulated. These genes were strongly correlated with transcriptomic markers of disease activity. Using this gene signature, support vector machine models accurately identified GM, achieving an area under the curve of 99.6% (99.0–99.9%) and an accuracy of 98.6% (98.2–98.9%). Among the identified genes, CHIT1 emerged as the most significantly upregulated gene, with its expression strongly correlating with disease severity. Furthermore, CHIT1 was detected at both the RNA and protein levels in granulomas and giant cells. Conclusion GM is transcriptomically characterized by a strong IFNγ signature and overexpression of proinflammatory cytokines, including IL1B, TNF and TGFB1. Additionally, it exhibits a unique transcriptomic profile, including CHIT1, which correlates with disease activity.

ABSTRACT Background Living kidney donation is a crucial option for addressing the global organ shortage and providing kidney transplantation for patients suffering from end‐stage kidney disease. Ensuring donor safety necessitates a comprehensive preoperative assessment of kidney anatomy and function. This study evaluates the relationship between kidney volumes derived from deep learning‐based MRI volumetry, intraoperative kidney volume measurements, split renal function measured by renal scintigraphy, and post‐donation eGFR. Deep learning‐based MRI volumetry is hypothesized to be a reliable method with good correlation. Methods This retrospective study analyzed 178 living kidney donors. Deep learning MRI volumetry‐based kidney volumes were compared with intraoperative volumes of the explanted donor kidneys obtained using the water displacement method. Additionally, MRI‐based volume ratios were compared with scintigraphy‐based split renal function ratios to determine their ability to predict the kidney with poorer renal function and post‐donation eGFR. Results Deep learning‐based MRI volumetry strongly correlated with intraoperatively measured kidney volumes (Pearson's correlation; r = 0.7671; p < 0.0001), confirming its precision in volume estimation. Although MRI‐based kidney volume ratios demonstrated only a moderate correlation with scintigraphy‐based split renal function ratios ( r = 0.4798), MRI volumetry correlated with 1‐year post‐donation eGFR. It tended to be better than renal scintigraphy ( r = 0.6829 versus r = 0.6191). Conclusion Deep learning‐based MRI volumetry is a reliable, non‐invasive tool for estimating kidney volumes in living donors, offering a radiation‐free alternative for preoperative assessment. While it differs from renal scintigraphy in evaluating split renal function ratios, its correlation with post‐donation eGFR tends to be better, supporting its potential role in living kidney donor assessment.

Abstract Purpose :Tamoxifen undergoes bioactivation to its active metabolite (Z)-endoxifen, which blocks estrogen-dependent breast tumor growth at high potency. We tested the feasibility and safety of supplementing standard tamoxifen therapy with low-dose (Z)-endoxifen in patients with breast cancer with compromised tamoxifen bioactivation. Patients and Methods :We conducted a prospective, interventional, three group randomized trial including 235 patients with hormone receptor–positive breast cancer who received standard tamoxifen therapy (20 mg/day). Patients were stratified by CYP2D6 genotype (n = 78), defining poor, intermediate, and normal metabolizers, or by baseline (Z)-endoxifen plasma concentration (n = 78), defining ≤15, 15 to 25, and ≥25 nmol/L. Co-treatment with (Z)-endoxifen 3 and 1.5 mg/day or placebo was performed, respectively. A control group (n = 79) received placebo regardless of metabolizer phenotype. The primary endpoint was the number of patients with (Z)-endoxifen levels &gt;32 nmol/L after 6 weeks of treatment. Adverse events were continuously monitored. Results: A higher proportion of patients in both intervention groups achieved target concentrations &gt;32 nmol/L compared with control (P &lt; 0.0001). At 3 mg (Z)-endoxifen supplementation, 92.3% of CYP2D6 poor metabolizer patients and all patients with baseline (Z)-endoxifen ≤15 nmol/L achieved the target concentration. At 1.5 mg (Z)-endoxifen supplementation, 88% of CYP2D6 intermediate metabolizer patients and 95% of patients with 15 to 25 nmol/L baseline (Z)-endoxifen levels achieved the target concentration. Similar proportions of patients receiving (Z)-endoxifen (6/80, 7.5%) or placebo (8/155, 5.2%) experienced grade 3 adverse events. Conclusions: Adding low-dose (Z)-endoxifen to standard tamoxifen is safe and provides a new approach to personalized antiestrogen treatment for patients with low endoxifen plasma levels.

Abstract Background: The neurokinin-1 receptor (NK1R) complex, activated by Substance P (SP), has emerged as a promising target. SP promotes cell growth, whereas its antagonist, Aprepitant (AP), used clinically for chemotherapy-induced nausea, has demonstrated anti-tumor activity. However, further insight on the anti-tumoral mechanisms after antagonistic targeting of the complex are required. Methods: We conducted bioinformatical analysis of public as well as own RNAseq data. Assays to assess cell proliferation and cell viability (MTT, scratch assays, colony formation) as well as apoptosis and autophagy were carried out. Metabolic changes were detected by SeaHorse analysis, ROS, NAD+/NADH, and MitoTracker. Results: Patient-derived organoid cultures showed reduced spheroid formation and altered morphology following AP treatment, while SP enhanced spheroid formation. SP promoted proliferation via Rho-kinase-dependent mechanisms and activated the ERK signaling pathway, with AP slightly reducing pERK levels. Further analyses revealed that AP induces apoptosis signaling without subsequent DNA fragmentation. Annexin V/PI staining indicated apoptosis induction after 24 hours, while subG1 analysis suggested a blockade in the apoptosis cascade. Prolonged AP exposure led to necrosis, which was mitigated by co-treatment with N-acetylcysteine. Western blot analysis confirmed caspase-9 and -3 activation but showed no PARP cleavage, likely due to high expression of inhibitors of apoptosis proteins (IAPs), such as XIAP. Conclusion: In conclusion, AP exhibits antiproliferative and cytotoxic effects in pancreatic tumor cells, potentially disrupting an autocrine/paracrine SP-NK1R feedback loop and altering metabolic resilience. Future studies should explore metabolic stress responses and investigate whether co-treatment could overcome incomplete apoptosis activation. Citation Format: Matthias Ilmer, Maximilian Viessmann, Bernhard Renz, Frank Braun, Jens Werner. Repurposing of the SP/NK1R-complex inhibitor aprepitant in hepatopancreatic malignancies [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research—Emerging Science Driving Transformative Solutions; Boston, MA; 2025 Sep 28-Oct 1; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_3):Abstract nr B023.

Abstract Purpose: Our goal was to determine if the HRDefine biomarker combining methylation and mutation assessment of key homologous recombination repair genes identifies BRCA wildtype (BRCAwt) ovarian cancer (OC) with outcomes similar to BRCA mutated (BRCAm) OC within the context of a frontline PARP inhibitor trial for advanced ovarian cancer. Methods: We performed an exploratory biomarker analysis of blood and neoplastic samples from the VELIA trial, a phase 3 study evaluating the PARP inhibitor veliparib as frontline maintenance therapy in OC. We developed a highly sensitive droplet digital PCR assay for quantitative BRCA1 and RAD51C promoter methylation and assessed germline/somatic mutations using the BROCA next generation sequencing platform. Cases were grouped into: BRCAm, HRDefine positive (BRCAwt HRDefine+), and HRDefine negative (BRCAwt HRDefine-). Carcinomas were considered HRDefine+ if quantitative BRCA1 or RAD51C promoter methylation was &gt;/= 60% or if a germline or somatic pathogenic variant (PV) was identified in the following non-BRCA HRR repair genes: RAD51C, RAD51D, PALB2, BARD1. For this analysis, the control group included the two study arms with placebo maintenance compared to the investigational arm of veliparib with chemotherapy and continued as maintenance (veliparib throughout group). HRDefine was compared to the Myriad genomic instability score (GIS) used as HRD assessment in the trial. Progression free survival (PFS) was compared using log rank tests. Results: Among 1140 VELIA participants, biomarker analysis could be performed for 487 cases. Of these, 255 (52%) were BRCAm, 60 (12%) were BRCAwt HRDefine+, and 172 (35%) were BRCAwt HRDefine-. BRCAwt HRDefine+ was driven by promoter methylation (57%), germline (40%), or somatic (3%) PVs. Median PFS (months, all arms combined) was 26 months (BRCAm), 27 months (BRCAwt HRDefine+), and 15 months (BRCAwt HRDefine-), with corresponding hazard ratios (HR) of 0.50 (95% CI: 0.39-0.65) and 0.50 (0.34-0.73) versus HRDefine-. All HRDefine+ molecular subgroups were associated with longer PFS, including RAD51C/D mutations (HR 0.44, 0.25-0.77) and promoter methylation (HR 0.60, 0.36-0.97). HRDefine positivity was significantly associated with improved PFS compared to HRDefine-/GIS low (n=60 vs n=111, median PFS 27 versus 14 months, HR 0.44, 0.30-0.65), while the HRDefine- cases with high GIS demonstrated a trend toward an intermediate PFS (n=56, median 18 months, HR 0.67, 0.45-1.01). When compared by treatment arm, median PFS was significantly longer in the veliparib throughout arm compared to control only for the BRCAm group (32 months vs 23 months, HR 0.61, 0.42-0.87), though the analysis was underpowered for the BRCAwt HRDefine+ sub-group (30 months vs 25 months, HR 0.79, 0.4-1.57). Conclusions: HRDefine identifies BRCAwt OC associated with a PFS that is like that of BRCAm cases and may improve stratification for PARP inhibitor therapy beyond current HRD assays. GIS may have some, albeit reduced, prognostic implication that is independent of HRDefine. Citation Format: Isabel V. Rodriguez, Marc Radke, Ronit Katz, Persephone Miller, Paula Ladd, Nithisha Khasnavis, Jennifer Ochoa, Melanie Dillon, Heather Lankes, Peter Ansell, Carol Aghajanian, Gini Fleming, Michael Birrer, Scott Kaufmann, Charles Leath, Kathleen Moore, Theresa Werner, Linda Van Le, Robert L. Coleman, Elizabeth M. Swisher. Application of HRDefine: a biomarker for identifying root causes of homologous recombination deficiency to a phase 3, randomized, placebo-controlled trial of veliparib in front-line treatment of advanced ovarian cancer (VELIA/GOG-3005) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Ovarian Cancer Research; 2025 Sep 19-21; Denver, CO. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl):Abstract nr A044.

ABSTRACT Aims Sarcoid myopathy (SaM) is characterised by granulomatous myositis (GM) and can overlap with inclusion body myositis (IBM), a late‐onset chronic idiopathic inflammatory myopathy with a still enigmatic pathogenesis. As GM can occur in different clinical contexts, we aimed to examine the histomorphologic features and gene expression profiles in cases of definite SaM that may inform diagnostic and therapeutic considerations. Methods We performed a multidimensional characterisation of muscle biopsy specimens from patients with ‘pure SaM’ (n=17), SaM with concomitant IBM (SaM‐IBM) (n=2), including histopathologic and ultrastructural analysis in addition to quantitative real‐time polymerase chain reaction. Additionally, bulk RNA sequencing was performed on 38 muscle biopsy specimens from patients with SaM (including SaM‐IBM) (n=30) and NGI (n=8). Results Histopathological analysis revealed a pattern of endomysial and perimysial granulomatous inflammation frequently extending to the fascia, endomysial fibrosis, muscle fibre atrophy, variation in muscle fibre size and capillary thickening. Findings from immunohistochemical studies established Chitinase 1 as a pure giant cell marker in SaM. On a subcellular level, ‘pure SaM’ was characterised by focal accumulation of large swollen mitochondria with rare cristae but an absence of irregular cristae. Transcriptomic analysis of patients with SaM confirmed markedly elevated expression of both type 1 and type 2 human leukocyte antigen molecules. Macrophage activity markers were highly elevated. Consistent with histologic findings, CHIT1 was specifically overexpressed in SaM samples but not in ‘pure IBM’ muscle biopsy specimens. Conclusions SaM is characterised by a stereotypical appearance at the histopathologic level and disease‐specific immune dysregulation that involves macrophage function and maturation. SaM‐IBM represents a noteworthy overlap syndrome that shares multiple dysregulated immune pathways with ‘pure SaM’.

Abstract Rationale Pulmonary hypertension (PH) in interstitial lung disease (ILD) lacks approved therapies. Objectives The Pulmonary Vascular Research Institute GoDeep metaregistry collects real-world data of patients with PH from international PH referral centers. Methods Patients with ILD-PH and relevant subgroups (idiopathic interstitial pneumonia [IIP], idiopathic pulmonary fibrosis [IPF]) were stratified by pulmonary vascular resistance (PVR). Kaplan-Meier survival analyses and adjusted Cox proportional hazards models were employed, additionally accounting for immortal time bias, sensitivity analyses, Heller explained relative risk statistics, and target trial emulation framework analysis. Measurements and Main Results Among 34,482 patients, 940 with hemodynamically fully characterized incident ILD-PH (median age, 67 [IQR, 59–74] yr) were identified. A total of 62% had severe ILD-PH with PVR &gt;5 Wood units (WU) and poor survival rates (29% and 18% at 3 and 5 yr), significantly worse than patients with ILD-PH with PVR ≤5 WU and patients with pulmonary arterial hypertension. Survival was poorest in severe IPF-PH. A total of 59% of all patients ILD-PH received PH-targeted therapy, predominantly phosphodiesterase-5 inhibitors (PDE5is). PDE5i treatment was consistently associated with significantly improved survival in patients with severe PH (hazard ratios of 0.537 [0.370–0.781], 0.461 [0.233–0.913], and 0.435 [0.215–0.8] for IIP-PH, IPF-PH, and IIP-PH with nintedanib/pirfenidone background therapy), but not in patients with less severe hemodynamic impairment, supported by sensitivity analyses, Heller statistics, and target trial emulation framework analysis. The survival statistics of patients with PDE5i-treated IIP-PH or IPF-PH were validated in the independent COMPERA registry. Combination therapy with PDE5is and inhaled prostacyclin analogues was superior to monotherapy using PDE5is (hazard ratio, 0.341; 0.205–0.566). Conclusions Prognosis in ILD-PH was generally very poor and was related to PH severity. PDE5i treatment in severe IIP-PH and IPF-PH was associated with improved survival, which is to be further verified in controlled trials.