Burn et al. reveal a previously unrecognised, non-catalytic function of myeloperoxidase (MPO) in neutrophil extracellular trap (NET) formation; integrating super-resolution microscopy and biochemical approaches, they demonstrated that MPO’s oligomeric state governs chromatin decondensation, redefining MPO as a structural chromatin modifier with implications for diseases driven by dysregulated NETosis.

Recent research has shown that sequential colonization of the skin by various subsets of immune cells, particularly T cells, during perinatal stages forms layered surveillance networks crucial for maintaining skin tissue integrity and function. Here, we review our current understanding of key epigenetic and molecular mechanisms, along with maternal/external environmental factors, that regulate the sequential colonization of skin by different T cell subsets and their roles in establishing and maintaining skin tissue homeostasis. We propose that establishment of a skin-resident T cell system is developmentally programmed in coordination with maturation of skin structural barriers to adapt to environmental changes during perinatal stages, while dysregulation during this critical ‘window of opportunity’ could have lifelong impacts on the health of both the skin and body.

The NLRP3 inflammasome plays a central role in host defense against microbial infections but also contributes to inflammatory diseases. Functioning of NLRP3 strictly relies on two signals: a ‘priming signal’ that licenses NLRP3 activity and an ‘activation signal’ that triggers inflammasome assembly and downstream caspase-1 activation. The priming signal involves transcriptional upregulation of NLRP3 and diverse post-translational modifications that regulate its stability, subcellular localization, and protein–protein interactions. This multilayered regulation prevents untimely inflammasome activation while enabling its rapid assembly when both priming and activation signals are present. Here, we focus on the complexity of the priming signal and critically analyze and discuss how diverse post-translational modifications cooperate to prime NLRP3, controlling its activity in health and disease.

HIV-1 persists lifelong despite effective antiretroviral therapy, yet the mechanisms underlying this persistence remain incompletely understood. Recent work by Wei et al. and Gao et al. reveals that the transcription factor BACH2 orchestrates CD4+ T cell memory programs fostering long-term memory formation while limiting effector differentiation, thereby promoting HIV-1 persistence.

Germinal center B cell–like diffuse large B cell lymphoma (GCB-DLBCL) originates from the malignant transformation of germinal center B cells. This process is driven by transcriptional and epigenetic dysregulations, frequently caused by recurrent mutations and chromosomal translocations. These changes lead to a differentiation arrest associated with unchecked proliferation and survival. This review highlights key transcriptional and epigenetic dependencies that sustain the GCB-DLBCL phenotype and identifies therapeutic vulnerabilities. Epigenetic targeting of these vulnerabilities unlocks tumor cells from their differentiation arrest, enabling further yet incomplete differentiation toward an antiproliferative, proapoptotic plasma cell–like or memory B cell–like state. We define this transition as an epigenetically programmed identity crisis, a promising therapeutic strategy to target GCB-DLBCL and potentially other malignancies.

Trained immunity (TRIM) is a de facto form of innate immune memory. While histone modifications contribute to TRIM, their reversible nature and susceptibility to dilution during cell division cannot fully account for its long-term persistence. Here, we propose that DNA methylation patterns, particularly hypomethylation at proinflammatory gene loci, could serve as a key epigenetic mechanism contributing to long-term TRIM. Mechanistically, these hypomethylated states are biochemically stable and faithfully inherited through cell division, acting as a permissive scaffold that enables the rapid accumulation of activating histone marks upon restimulation. This DNA-methylation-mediated process could underpin the durability of TRIM across multiple contexts, including hematopoietic stem cell self-renewal, differentiation from central to peripheral compartments, and autonomy of tissue-resident cells.

Orthoflaviviruses – including dengue, Zika, yellow fever, Japanese encephalitis, and Powassan viruses – are mosquito- and tick-borne members of the family Flaviviridae. Orthoflaviviruses pose major public health threats, with the potential for epidemics and pandemics. Lipid nanoparticle (LNP)-encapsulated nucleoside-modified mRNA vaccines offer a powerful platform by delivering in vitro-synthesized viral antigen-encoding mRNAs into the host, where they generate proteins that trigger robust immune responses. These synthetic platforms simplify the expression of complex viral glycoproteins, allow rapid and scalable manufacturing that is critical in a pandemic/epidemic scenario, and support multivalent designs to broaden protection. This review highlights recent advancements in mRNA vaccines for orthoflaviviruses and examines how innovations in antigen design and delivery platforms may offer broad, safe, and durable protection against diverse pathogenic orthoflaviviruses.

This essay uses immunology to illuminate human relationships. Moving beyond self/non-self toward danger-based models, it draws parallels between cytokine communication and language, tolerance and forgiveness, microbiota diversity and coexistence. Recognizing these metaphors reveals pathways toward healthier connections within individuals, communities, and societies.

Maternal immune activation (MIA), triggered by infection or inflammation during pregnancy, is a well-recognized risk factor for neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD). Clinical cohort studies and rodent models suggest that natural killer (NK) cells play a significant role in NDD pathogenesis, but the underlying mechanisms remain poorly defined. Here, we summarize the key immune mediators involved in MIA-induced NDDs, emphasizing microglia as a central hub. We then examine emerging evidence implicating aberrant NK cell activation in ASD, underscoring their overlooked contribution to impaired neurodevelopment. Finally, we discuss potential mechanisms of NK cell–microglia crosstalk in NDDs. Elucidating these interactions in the context of MIA will be crucial for developing preventive and therapeutic strategies against inflammation-driven NDDs.

Traumatic brain injury (TBI) is a leading cause of neurological disability, associated with higher rates of cognitive complications that negatively affect recovery. Myriad cytokine and chemokine pathways propagate the secondary responses to injury. This review discusses the integration of peripheral and central immune cytokine and chemokine signaling cascades after TBI and recovery, with a focus on preclinical work. We first discuss key cytokine and chemokine interactions influencing recovery and long-term deficits. Next, we discuss the major cell types that propagate and respond to the inflammatory process after TBI. Understanding neuroimmune signaling, utilizing recent advances in transcriptomics and immune profiling, with a focus on cytokines and chemokine after TBI reveals therapeutic targets and informs strategies to improve long-term recovery and outcomes.

Sepsis, a life-threatening condition triggered by infection, disrupts the body’s immune balance and remains a major global health challenge. This forum explores the dual roles of cytokines in sepsis: their overactivation drives ‘cytokine storms,’ and dysregulation leads to immunosuppression. It also discusses regulatory mechanisms for developing targeted therapies.

Studies of the biological effects of Fas signaling, using transformed cell lines as targets, indicate that ligation of the Fas receptor induces an apoptotic death signal. Chronically activated normal ...

The evolution of the fetal immune system within the womb is a delicate balancing act: it is trained to not reject maternal antigens, while equipping itself with ‘learned’ immunity to survive and thrive in the outside world. In this opinion article, we propose that a deliberate maternal touch via immune and nutritional influences, orchestrated, in part, by microbiota-derived components, imprints the fetal immune system with the needed immune memory and epigenetic marks to navigate a far less nurturing outside world, including early microbial colonizers in the newborn’s intestine, pathogens and irritants, and allergens in food. We redefine the hygiene hypothesis to include prenatal maternal microbial exposures, priming fetal immune development for long-term fitness and reduced inflammatory/autoimmune disease risk.

Salmonella enterica serovar Typhimurium (STm) represents a major global health burden. Strains endemic in sub-Saharan Africa cause life-threatening invasive non-typhoidal salmonellosis (iNTS) in vulnerable populations. Studies in the iNTS-like mouse model show that STm induces profound germinal centre (GC) disruption, impairing high-affinity, long-lived antibody and memory B cell formation – affecting nascent and pre-existing GC reactions. Lipopolysaccharide (LPS) and specific STm type 3 secretion effectors drive GC collapse, but the determining bacteria–host interactions are still unclear. Although STm induces an extrafollicular (EF) B cell response generating protective antibodies, their longevity remains unclear. With no licensed human vaccine for iNTS, we propose that vaccine strategies should consider ways to protect GC integrity and include GC parameters as endpoints in preclinical trials.

The complement genes harbour genetic variants that affect numerous diseases; however, these genes are notoriously repeat-heavy, and these repeat regions are largely unexplored for disease-relevant genetic variation. Elucidating these ‘dark’ regions is now possible using long-read sequencing (LRS), enabling identification of novel disease-relevant genetic variants.

Intrahepatic immune responses are often insufficient to control hepatitis virus infections. A recent study by Venzin and colleagues demonstrates a detailed mechanism by which an intrahepatic tricellular network and the cytokine IL-27 can augment virus-specific immunity.

Mucocutaneous surfaces rely on IL-17–producing lymphocytes to preserve barrier integrity and prevent bacterial and fungal overgrowth. Accordingly, genetic or pharmacological IL-17 deficiencies lead to mucocutaneous infections. Interferon (IFN)-γ mediates host defense against intracellular pathogens, but excessive mucosal IFN-γ activity can paradoxically impair epithelial integrity and promote infection, as shown in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy–associated oral candidiasis, even with intact IL-17 responses. Further evidence for IFN-γ–driven pathology is emerging in bacterial, fungal, and protozoal infections at mucocutaneous tissues. Together, these findings support a model in which IL-17 promotes barrier resistance, whereas unchecked IFN-γ erodes it. Collectively, they advance the concept that although mucocutaneous infections are classically caused by immunodeficiency, epithelial disruption by immunopathology represents a novel and underappreciated mechanism of infection susceptibility at barrier sites.

Mosaic errors of immunity (MEI) encompass a group of immune disorders caused by somatic or gonosomal gene variants affecting hematopoiesis and immune function. Although the causal role of mosaicism in monogenic immune disorders has been recognized for over two decades, our understanding of their pathogenesis, genotype–phenotype correlation and clonal evolution remains poor. In this review, we synthesize shared and distinct molecular determinants from the currently recognized MEI and provide a mechanistic framework for future research. Exploring the implications of mosaic genetic variation in patients with unexplained immune disorders could uncover novel, actionable genetic disorders. Moreover, the study of these rare ‘experiments of nature’ may shed light on cell-specific immune pathways, non-malignant clonal dynamics, and mosaic disorders more broadly.