Immunology
Abstract
Mixed hematopoietic chimerism after hematopoietic cell transplantation (HCT) can modulate the immune system and induce tolerance to allogeneic tissues. However, bone marrow conditioning-related toxicities preclude wider adoption of HCT for transplant allotolerance. We sought agents that reduced conditioning intensity, while promoting durable mixed chimerism after HCT across complete major histocompatibility complex (MHC) mismatch in diabetic mice, permitting islet allotransplantation and diabetes reversal. We systematically tested baricitinib (JAK1/2 inhibitor), venetoclax (Bcl2 inhibitor), and αCD47 antibody, agents in current clinical use, and quantified hematopoietic chimerism after HCT. Combined with αCD117 antibody, transient T cell depletion, and just 10 centigray (cGy) total body irradiation (TBI), these agents enabled durable mixed chimerism and matching allo-islet tolerance, to cure diabetes without evidence of GVHD. Thus, we have developed a conditioning regimen to promote allogeneic mixed hematopoietic chimerism and transplanted islet allotolerance that minimizes conditioning radiation and cures diabetes, a significant achievement.
Authors
Stephan A. Ramos, Preksha Bhagchandani, Diego M. Burgos, Xueying Gu, Richard Rodriguez, Nadia Nourin, Martin Neukam, Shiva Pathak, Judith Shizuru, Seung K. Kim
Abstract
Although inflammatory complications are common in preterm infants, the effects of these conditions on neonatal immune development remain poorly defined. We therefore investigated whether severe bronchopulmonary dysplasia (BPD) and systemic infection, two major complications of prematurity, produce distinct immune signatures and change immune composition over time. We performed longitudinal high-dimensional immune profiling of residual whole blood from 38 preterm infants sampled every two weeks, along with 10 term infants at birth. Preterm infants with severe BPD showed a progressive increase in Th17-polarized CD4+ T cells, neutrophils, and Th17-related cytokines compared to age-matched infants with moderate BPD. In contrast, some preterm infants with systemic bacterial or viral infections mounted exceptionally robust CD8+, CD4+, and γδ T cell responses, with oligoclonal expansion, terminal differentiation, and coordinated plasma cytokine shifts that persisted well beyond resolution of infection. These findings demonstrate that different preterm comorbidities imprint the neonatal immune system in divergent ways. Thus, comprehensive and longitudinal immune profiling may not only identify connections between clinical inflammatory complications and underlying immune pathways but also reveal potential targets for intervention.
Authors
Benjamin A. Fensterheim, Michelle L. McKeague, Divij Mathew, Shwetank, Ajinkya Pattekar, Matthew Lee, Zahabia Rangwala, Sean Nasta, Macy C. Kee, Cynthia Clendenin, Zachary Martinez, Caroline Diorio, Allison R. Greenplate, Krithika Lingappan, E. John Wherry
Abstract
Natural killer (NK) cells are pivotal in the early immune response to Plasmodium falciparum infection, yet their functional dynamics and regulation remain incompletely understood. In a longitudinal study of malaria patients in a non-endemic setting, we observed a transient but potent activation of NK cell cytotoxicity during acute malaria, characterized by rapid granzyme B-mediated killing and elevated expression of genes associated with cytotoxicity (PRF1, GZMB, and GZMA). This heightened activity was supported by increased plasma levels of granzymes and proinflammatory cytokines, which enhanced NK cell function in vitro. However, plasma samples from clinical malaria also contained inhibitory mediators, including soluble cytokine receptors, which dampened NK cell responses. These findings reveal that the host microenvironment orchestrates a tightly regulated NK cell response that potentiates cytotoxicity during acute infection and rapidly downmodulate it after treatment. Understanding this balance between activation and suppression may inform strategies to harness NK cells for malaria control while minimizing immunopathology.
Authors
Pengjun Xi, Patrick A. Sandoz, Maximilian Julius Lautenbach, Eleni Bilev, Björn Önfelt, Anna Färnert, Quirin Hammer, Christopher Sundling
Abstract
Sepsis is a leading cause of death for which host-directed therapies are urgently needed. We performed high-dimensional flow cytometry, measurement of soluble biomarkers, and lipopolysaccharide (LPS) stimulation of neutrophils to characterize neutrophil heterogeneity and function in patients with sepsis. We observed that in sepsis patients, low-density neutrophils (LDNs) are elevated and phenotypically diverse populations of innate immune cells with varying degrees of maturity and myeloperoxidase expression. Spleen tyrosine kinase (SYK) expression was found to be higher in whole blood neutrophils and LDNs of sepsis patients compared to healthy donors. Importantly, SYK+LDNs associated with increased levels of intracellular myeloperoxidase (MPO) and soluble biomarkers. Furthermore, SYK+LDNs correlated with clinical outcomes of sepsis disease severity including sequential organ failure assessment (SOFA) score, mechanical ventilation, and vasopressors. Functionally, the SYK inhibitor R406 suppressed changes in neutrophil features of activation from normal-density neutrophils and LDNs including the SYK+ and SYK- neutrophil subsets and MPO release from LDNs following LPS stimulation of sepsis neutrophils. Combined, these results establish LDNs as a heterogenous population of neutrophils that express high levels of SYK and support SYK inhibition as a novel therapeutic target aimed at suppressing overactive neutrophils in sepsis.
Authors
Heather L. Teague, Lauren Knabe, Raquel S. Da Cruz, Xianglan Yao, Kiana C. Allen, Trenton Williams, Cumhur Y. Demirkale, Merte Woldehanna, Ernest Evans, Amir Hobson, Jared D. Wilkinson, Steven D. Nathan, Christopher S. King, Jeffrey R. Strich
Abstract
BACKGROUND. IL-7 is a critical cytokine in T cell development, survival, and homeostasis. Previous preclinical and clinical studies reported that IL-7 treatment increased T cell counts, but its effect on peripheral blood T cells in cancer patients and molecular mechanisms have not been explored. METHODS. We investigated effects of long-acting recombinant human interleukin-7 (rhIL-7-hyFc) on peripheral T cells in patients with advanced solid tumors. Peripheral blood samples were collected before and after treatment, followed by analysis through single-cell transcriptomics and flow cytometry. RESULTS. We found that rhIL-7-hyFc induced marked expansion of proliferating T cells, and promoted transcriptional changes associated with immune activation, cell cycle progression, and anti-apoptosis. Trajectory analysis revealed that post-treatment T cells had distinct transcriptional states enriched for cytokine- and TCR-mediated signaling pathways. Notably, a second dose administered after three weeks yielded diminished proliferation and minimal transcriptional changes, which were independent of antidrug antibody or CD127 downmodulation. Examination of elements of the IL-7 signaling pathway revealed intact proximal signaling (e.g., STAT5 phosphorylation) but downregulation of distal elements, including PIM-1 kinase and c-Myc. CONCLUSIONS. Our results demonstrate that rhIL-7-hyFc induces robust peripheral T-cell expansion and activation in patients with solid tumors, supporting its potential use for lymphopenic patients treated with cancer immunotherapy. TRIAL REGISTRATION. NCT03478995, NCT03619239. FUNDING. NRF-2022R1A2C3007292, RS-2024-00439160, RS-2025-02213409, RS-2025-25460003
Authors
Ho Cheol Jang, Jeong Yeon Kim, Sojeong Kim, Heewon Kim, Mi-Sun Byun, Myung Ah Lee, Jong Hee Chang, Do-Hyun Nam, Tae Won Kim, Sin-Soo Jeun, Joohyuk Sohn, Su-Hyung Park, Eui-Cheol Shin
Abstract
BACKGROUND. Disseminated coccidioidomycosis (DCM) is an often fatal and otherwise intractable condition requiring lifelong antifungal treatment. We have previously shown that a deranged polarization of CD4+ T cells toward a Th2 phenotype can exist in the context of DCM. Here we studied a large population of subjects to determine the frequency of abnormal Th2 skewing of CD4+ T cells in patients with coccidioidomycosis and to identify underlying genetic mechanisms supporting this phenotype. METHODS. We collected peripheral blood mononuclear cells from 204 patients with coccidioidomycosis, including 96 patients with disseminated disease. We measured immune phenotypes and cytokine production by CD4+ T cells from patients and healthy controls, and comparisons between groups were made based on disease severity and demographics. Whole genome sequencing was conducted on 180 individuals who also had cytokine profiling. RESULTS. We found that ~25% of DCM patients had a CD4+ T-cell compartment that was abnormally skewed toward a Th2 phenotype, and Th2 skewing was highly correlated with male sex. Co-culture of T cells with the IL4R/IL13R-blocking antibody dupilumab reduced Th2 skewing. Sequencing revealed rare variants in genes involved in the IL-12-IFN-γ axis in several Th2-skewed patients, and we validated one such variant in IFNGR1 as hypomorphic. CONCLUSION. Patients with DCM, especially males, should be screened for Th2 skewing of CD4+ T cells. Patients with Th2 skewing should be additionally screened for genetic defects in the IL-12-IFN-γ axis. Our findings give a mechanistic rationale for blockade of IL4R in Th2-skewed patients with refractory coccidioidomycosis.
Authors
Timothy J. Thauland, Smriti S. Nagarajan, Alexis V. Stephens, Samantha L. Jensen, Anviksha Srivastava, Miguel A. Moreno Lastre, Terrie S. Ahn, Chantana Bun, Michael T. Trump, Royce H. Johnson, George R. Thompson III, Maria I. Garcia-Lloret, Valerie A. Arboleda, Manish J. Butte
Abstract
Background. Coccidioidomycosis ranges from self-limiting Uncomplicated Valley Fever (UVF) in most cases to life-threatening Disseminated Coccidioidomycosis (DCM) in rare individuals. A few patterns of immunologic deficits allowing for dissemination have been identified, though the specific defects in most individuals with DCM remain undefined. We hypothesized that chronic antigen exposure in DCM engenders a state of T cell exhaustion. Methods. From a cohort of over 300 subjects with confirmed diagnoses of coccidioidomycosis, circulating T cell phenotypes were characterized via flow cytometry and Coccidioides-specific T cell responses were measured by Activation-Induced Marker (AIM) assay. Results. Male sex was significantly associated with disseminated disease (odds ratio 2.5; 95% CI: 1.5 – 4.0). 52% of subjects showed Coccidioides-specific T cell responses in our AIM assay. We noted a significant difference in subjects sampled in the first year of diagnosis, where only 8% of DCM subjects had T cell responses during this time, as compared to 44% of UVF subjects (p = 0.04). Among DCM patients with detectable AIM responses, CD4+ T cells demonstrated an exhausted phenotype with elevated PD-1 expression compared to UVF subjects. In vitro PD-1 blockade augmented IFNγ production in most tested DCM subjects. Conclusion. These findings suggest that dissemination may occur in some individuals during a period of impaired antigen-specific T-cell activity. Importantly, these responses can be augmented in vitro by PD-1 blocking antibodies, supporting further study of immune checkpoint therapy as an adjunct to antifungal treatment in disseminated coccidioidomycosis.
Authors
Gregory D. Whitehill, Alexis V. Stephens, Timothy J. Thauland, Miguel A. Moreno Lastre, Matthew M. Tate, Sinem Beyhan, Royce H. Johnson, George R. Thompson III, Maria Garcia-Lloret, Manish J. Butte
Abstract
Systemic inflammation is now recognized as a key contributor to epilepsy pathophysiology, yet the role of innate immune cells, particularly neutrophils, remains poorly defined in epilepsy. While preclinical studies in rodent models have implicated neutrophils in seizure activity, their phenotype in human epilepsy has not been thoroughly investigated. In this study, we aimed to characterize systemic inflammatory profiles and neutrophil-associated immune signatures in the blood of patients with drug-resistant epilepsy, compared to healthy controls. We identified a systemic low-grade inflammatory profile in patients, characterized by elevated neutrophil-to-lymphocyte ratio, C-reactive protein, pro-inflammatory cytokines (IL-6, CXCL8/IL-8, TNF-α), and activated neutrophils (CXCR4+CD62Llow). Neutrophil phenotyping revealed two distinct immune profiles. Patients with longer disease duration exhibited a more immature systemic signature, characterized by immature neutrophils (CD15⁺CD10⁻), resting neutrophils (CXCR4⁺CD62L⁺), and elevated IL-6 levels. In contrast, patients with higher seizure frequency displayed a more inflammatory profile, marked by increased IL-12 and activated (CXCR4+CD62Llow) and hyperactivated (CXCR4highCD62Llow) neutrophil subsets. Moreover, elevated pre-surgical levels of inflammatory profile TNF-α, IL-6, and hyperactivated CXCR4high CD62Llow neutrophils were associated with seizure recurrence one year after surgery. This pioneering study highlights the heterogeneity of peripheral immune responses in drug-resistant epilepsy and identifies neutrophil-related signatures as promising prognostic biomarkers in this context.
Authors
Coraly Simoës Da Gama, Aurelie Hanin, Gwen Goudard, Veronique Masson, Aurore Besnard, Karim Dorgham, Guy Gorochov, Guillaume Dorothee, Valerio Frazzini, Vincent Navarro, Mélanie Morin-Brureau
Abstract
Malnutrition, gut inflammation, and antibiotic-induced dysbiosis (AID) are well-recognized risk factors for poor clinical outcomes among critically ill patients. We previously showed that commercially available plant-based enteral nutrition (PBEN) preserves a commensal microbiome compared with commonly used artificial enteral nutrition (AEN). In this study, PBEN was superior to AEN in promoting recovery from antibiotic-induced dysbiosis in mice and humans. PBEN effectively mitigated anemia and leukopenia, restored naïve lymphocyte populations, and reduced bone marrow myeloid expansion. Animals randomized to PBEN also exhibited improved responses to infectious challenges following antibiotic exposure. A pilot clinical study validated these findings, demonstrating increased gut commensals, reduced pathogens, and improved leukocyte balance in critically ill children receiving PBEN compared with AEN. Together, these results suggest that PBEN offers a practical dietary approach to mitigate antibiotic-associated complications and potentially improve clinical outcomes among hospitalized patients requiring supplemental nutrition.
Authors
Mona Chatrizeh, Jianmin Tian, Matthew Rogers, Firuz Feturi, Guojun Wu, Brian Firek, Roman Nikonov, Lauren Cass, Alexandra Sheppeck, Lavnish Ojha, Ali Carroll, Matthew Henkel, Justin Azar, Rajesh K. Aneja, Brian Campfield, Dennis Simon, Michael J. Morowitz
Loss of Tumor-Infiltrating Lymphocytes and Poor Response to Immunotherapy in IDH GOF Mutant Melanoma
Abstract
Recent innovations in melanoma treatment with immune checkpoint blockade (ICB) have improved overall outcomes for patients, however over 50% of patients still develop resistance to treatment. These patients either have intrinsic resistance, and never respond to therapy, or develop acquired resistance months or years into treatment. The mechanisms underlying ICB resistance remain poorly understood. Our data shows that isocitrate dehydrogenase gain of function (IDH GOF) mutant melanoma patients have a worse response to anti-PD1 immunotherapy. IDH mutations have been found to be oncogenic and associated with differential methylation in multiple cancers but are not yet characterized in human melanoma. Here, we investigate the clinical, immune, and transcriptional phenotypes of IDH GOF melanomas through analyses of clinical response, single-cell RNA sequencing, bulk RNA sequencing, and DNA methylation data. Single-cell data analysis shows decreased immune infiltrate and activity in the IDH GOF tumors. Bulk sequencing data demonstrates the association between IDH mutation, immune exclusion, and disruptions in global DNA methylation. The melanoma-derived genomic data presented supports previously described resistance mechanisms of IDH mutation in other cancer types and is the first demonstration of the role of IDH GOF in the human melanoma tumor microenvironment.
Authors
Emma Specht, Lakshmi Pakanati, Meng-Ju Wu, Russell W. Jenkins, Derek N. Effiom, Nabeel Bardeesy, Bradley E. Bernstein, Moshe Sade-Feldman, Christine G. Lian, Genevieve M. Boland, Elena Torlai Triglia, Sonia Cohen
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