Human T cell leukemia virus type 1, the first human retrovirus ever identified, infects an estimated 5 to 10 million people worldwide, a figure extrapolated from surveys covering only about one-seventh of the global population. The virus inserts a DNA copy of its RNA genome into the chromosomes of host T cells, establishing a lifelong infection that can drive a spectrum of diseases, including adult T cell leukemia/lymphoma, HTLV-1-associated myelopathy, and HTLV-1-associated uveitis, a chronic inflammation inside the eye that is particularly common in endemic regions such as Japan. Despite the scale of the problem, coordinated global action has been slow; the World Health Organization only published technical reports aimed at reducing HTLV-1-related morbidity and mortality in 2021, and no broadly effective intervention has emerged in decades of research.

Current treatment for the ocular disease relies heavily on corticosteroids, delivered as topical drops, injections into the eye, or oral prednisone. This approach has serious shortcomings. Studies indicate that 30 to 60 percent of patients with HTLV-1-associated uveitis experience recurrent episodes, and long-term steroid exposure can trigger cataracts, glaucoma, macular edema, epiretinal membranes, retinal degeneration, optic nerve atrophy, and bullous keratopathy. Most importantly, corticosteroids suppress inflammation without reducing the number of virus-infected cells or halting disease progression. Newer molecular targeted agents, including the anti-CCR4 antibody mogamulizumab and the immunomodulatory drug lenalidomide, have been explored, but treatment-related inflammation and adverse effects remain significant obstacles. This therapeutic gap motivated a team led by Yaru Zou and Koju Kamoi of Tokyo Medical and Dental University to investigate whether an epigenetic drug already approved for blood cancer could address the root of the ocular inflammation.

The drug in question is valemetostat, marketed as EZHARMIA, a dual inhibitor of the enzymes EZH1 and EZH2 that was approved in 2022 for adult T cell leukemia/lymphoma. Both enzymes are the catalytic components of polycomb repressive complex 2, a molecular machine that silences genes by adding three methyl groups to lysine 27 on histone H3, producing the repressive chromatin mark known as H3K27me3. Previous work had shown that EZH1 and EZH2 are overexpressed, and H3K27me3 deposition increased, in ATL cells and in cells expressing the viral oncoprotein Tax. Dual EZH1/2 inhibitors have also been reported to curb the spontaneous proliferation and exaggerated immune responses of HTLV-1-infected cells in patients with HTLV-1-associated myelopathy. What remained unknown was whether such inhibition could benefit the inflamed eye.

To find out, the researchers built a series of laboratory models centered on ARPE-19 cells, a human retinal pigment epithelial cell line chosen because the retinal pigment epithelium forms the outer blood-retinal barrier and governs retinal immune homeostasis. They exposed these ocular cells to three kinds of T cells: MT-2 cells, which carry transcriptionally active HTLV-1 and express the viral protein Tax; TL-Om1 cells, an ATL-derived line in which the virus is largely silent and Tax is low or absent; and Jurkat cells, which are uninfected and served as controls. In parallel, they treated the T cell lines themselves. Western blotting and quantitative PCR revealed that HTLV-1 infection drove significant upregulation of both EZH1 and EZH2, along with elevated H3K27me3, in infected retinal pigment epithelial cells and in MT-2 cells, with EZH1 protein rising roughly 2.5-fold in infected ocular cells and six-fold in MT-2 cells. This was the first demonstration that HTLV-1 infection induces polycomb-mediated epigenetic changes in retinal cells.

The team then treated the models with valemetostat at 0.01, 0.1, and 1 micromolar for 96 hours, concentrations selected in preliminary experiments because they harmed infected T cells while leaving normal ocular cells, including primary human trabecular meshwork cells, unaffected below 10 micromolar. The results were strikingly dependent on the model. In co-cultures of retinal cells with Tax-positive MT-2 cells, and in retinal cells directly infected with HTLV-1, the drug produced modest but statistically significant reductions in cell viability at the highest dose, accompanied by small increases in late-stage apoptosis. No such effects appeared in co-cultures with TL-Om1 or Jurkat cells. Crucially, the absolute magnitude of apoptosis remained limited, typically only 1 to 3 percent above baseline, indicating that valemetostat is not broadly toxic to retinal cells, an important safety consideration given their role in maintaining vision.

The virological findings were equally nuanced. Valemetostat did not significantly reduce the HTLV-1 proviral load in co-culture systems or in directly infected retinal pigment epithelial cells. However, in MT-2 cells themselves, 1 micromolar valemetostat significantly lowered proviral load and suppressed the messenger RNA levels of both Tax and HBZ, the two hallmark transcripts of the virus. Because MT-2 cells represent the transcriptionally active, highly infectious state of HTLV-1, while TL-Om1 represents latency, the results suggest that the drug’s antiviral effect is gated by the transcriptional status of the infected cell. Within the four-day treatment window, the authors conclude, valemetostat’s benefit to the ocular environment is likely indirect, acting primarily by quieting the most virally active cells rather than by eradicating provirus everywhere.

The most clinically relevant effects emerged in the inflammatory readouts. HTLV-1-infected T cells recovered from the eyes of patients with uveitis are known to secrete copious interleukin-6, interleukin-8, and interleukin-10, all implicated in disease. In the new study, valemetostat produced a dose-dependent increase in the anti-inflammatory cytokine IL-10 in MT-2-containing conditions, significant at 1 micromolar in the co-culture system and across all doses in MT-2 cells. This fits a mechanistic expectation: blocking EZH1/2 removes H3K27me3 marks that repress the IL-10 gene, and prior genetic studies showed that loss of EZH2 directly activates IL-10 transcription in several CD4-positive T cell subsets. Meanwhile, pro-inflammatory signals fell in a context-dependent pattern. IL-12p70 and the chemokine CXCL-10 dropped in co-cultures, IL-6 and IL-8 declined mainly in MT-2 cells, and CCL-2 fell at low doses in the MT-2 co-culture, whereas the chemokine CCL-5 was unchanged in every model.

The drug’s influence on NF-kappaB, the central inflammatory pathway that Tax hijacks to drive both viral replication and cytokine production, was more subdued. Valemetostat modestly reduced NF-kappaB p65 phosphorylation in the MT-2 co-culture at the lowest dose and slightly decreased the nuclear-to-cytoplasmic ratio of p65 in retinal cells stimulated with TNF-alpha, but it did not abolish nuclear translocation. The authors attribute this to the overwhelming strength of Tax-driven NF-kappaB activation, which a 96-hour course of EZH1/2 inhibition may be insufficient to counteract, and to the fact that NF-kappaB and cytokine networks are regulated by many factors beyond polycomb complexes. Immunofluorescence confirmed that valemetostat significantly lowered H3K27me3 in retinal cells exposed to MT-2 cells or directly infected, but not in cells co-cultured with TL-Om1 or Jurkat cells, again underscoring the model dependence of the epigenetic response.

The study also carries a cautionary note about IL-10. Although the cytokine is anti-inflammatory, it can promote the survival of HTLV-1-infected T cells and facilitate immune evasion by impairing dendritic cell antigen presentation and downregulating MHC class I molecules, and patients with aggressive ATL often show abnormally elevated IL-10. The authors therefore suggest that combining EZH1/2 inhibition with IL-10 pathway blockade could prove more effective, noting evidence that IL-10 neutralization sensitizes ATL cells to standard therapies. In the TL-Om1 model of ATL-related ocular infiltration, valemetostat failed to reduce H3K27me3, proviral load, or NF-kappaB activation within the malignant cells, yet it suppressed TL-Om1-induced CXCL10 secretion and induced dose-dependent apoptosis, pointing to a benefit mediated through the inflammatory microenvironment rather than direct tumor killing.

The authors are candid about the limitations. The work relied entirely on in vitro co-cultures and established cell lines, which cannot reproduce the blood-retinal barrier, retinal architecture, or local immune regulation of a living eye, and the intraocular pharmacokinetics of valemetostat after systemic administration remain undefined. Sex as a biological variable could not be assessed because donor-defined primary cells were not used. Even so, the findings establish a proof of concept that an approved epigenetic therapy can counteract HTLV-1-induced chromatin changes in retinal cells, dampen viral transcription in the most active infected cells, and reshape the cytokine milieu that sustains uveitis. Longer treatment studies, in vivo models, and patient-derived systems will be needed to determine whether these modest, context-dependent effects can be translated into a genuine steroid-sparing therapy for one of the most burdensome manifestations of a virus that medicine has long neglected.

Subject of Research: EZH1/2-targeted epigenetic therapy with valemetostat for HTLV-1-associated uveitis

Article Title: Dual impact of EZH1/2-targeted therapy in HTLV-1-associated inflammation: Direct and indirect mechanisms

Article References: Zou, Y., Kamoi, K., Yang, M., Zong, Y., Zhang, J., & Ohno-Matsui, K. (2026). Dual impact of EZH1/2-targeted therapy in HTLV-1-associated inflammation: Direct and indirect mechanisms. iScience, 29(11), Article 117775. https://doi.org/10.1016/j.isci.2026.117775

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117775

Keywords: HTLV-1, valemetostat, EZH1, EZH2, H3K27me3, uveitis, epigenetics, PRC2, Tax, IL-10, NF-kappaB, retinal pigment epithelium

Even years after the acute phase of the COVID-19 pandemic faded from daily headlines, one of its most stubborn legacies continues to shadow millions of working adults: post-COVID conditions, the cluster of persistent symptoms now broadly known as long COVID. A new cross-sectional study from Taiwan, published in BMC Psychology, offers a sobering snapshot of what these conditions mean for mental health and the capacity to work, even among people who were highly vaccinated and infected predominantly during the milder Omicron era. The findings challenge a lingering assumption that vaccination and less virulent variants have fully neutralized the long-term occupational and psychological costs of SARS-CoV-2 infection.

The research, led by Jhe-Ping Lin of the Department of Occupational Medicine at Linkou Chang Gung Memorial Hospital in Taoyuan City, together with Chia-Cheng Chang, Chen-Chang Yang, Ting-An Yang and corresponding author Yu-Chung Tsao, set out to answer a question that has become increasingly urgent for occupational health practitioners worldwide: how do employed adults who report persistent post-COVID symptoms differ, in measurable psychological and functional terms, from infected peers who consider themselves fully recovered? Much of the existing long COVID literature emerged from populations infected with earlier viral variants, before widespread vaccination, and focused heavily on physical sequelae. Relatively less is known about the psychological and occupational footprint of post-COVID conditions under contemporary epidemiological conditions, which is precisely the gap the Taiwanese team sought to fill.

The study design was straightforward but methodologically deliberate. Employed adults with prior confirmed SARS-CoV-2 infection were recruited through clinical and occupational-health channels using non-probability sampling, a practical approach for reaching workers with documented infection histories. All participants completed a battery of validated questionnaires assessing four core domains: health-related quality of life, fear of COVID-19, insomnia severity and work ability. The investigators then divided the cohort into two groups based on whether participants reported persistent symptoms consistent with post-COVID conditions, and statistically compared the two groups on every psychological and occupational measure. This symptom-based categorization mirrors the approach increasingly favored internationally, since no single laboratory biomarker can yet reliably define long COVID.

The results were striking in their consistency. Participants reporting post-COVID conditions demonstrated significantly lower quality of life, with a mean difference of 13.9 points on the quality-of-life instrument compared with fully recovered peers. They also scored higher on the Fear of COVID-19 Scale, a validated measure of pandemic-related anxiety, and reported greater insomnia severity, suggesting that disturbed sleep is a common companion of persistent post-viral illness. Perhaps most consequential for employers and policymakers, the post-COVID group showed reduced scores on the Work Ability Index, a well-established instrument that quantifies how well a worker perceives themselves able to meet the physical and mental demands of their job. The mean difference of 3.3 points on this index may sound modest, but in occupational medicine research, shifts of this magnitude on the Work Ability Index are considered clinically meaningful and are associated with elevated risks of reduced productivity, prolonged sickness absence and early exit from the labor force.

To appreciate why these numbers matter, it helps to understand what each instrument measures. Health-related quality-of-life scales capture how illness erodes daily functioning across physical, emotional and social dimensions; a 13.9-point deficit represents a substantial perceived deterioration in wellbeing, not a marginal statistical blip. The Fear of COVID-19 Scale taps illness-related anxiety that can itself become disabling, feeding avoidance behaviors and hypervigilance. Insomnia severity indices quantify difficulties falling asleep, staying asleep and feeling restored by sleep, and chronic insomnia is strongly linked to depression, impaired concentration and workplace accidents. The Work Ability Index synthesizes a worker’s self-assessed physical and mental capacity, diagnosed illnesses and resources relative to job demands, making it one of the most predictive single measures available for future work disability. That all four domains moved in the same negative direction among the post-COVID group paints a coherent picture of a population under compounding psychological and functional strain.

Crucially, these associations emerged within a population that reflects the current reality of the pandemic rather than its early, pre-vaccine chapter. Taiwan maintained exceptionally high vaccination coverage, and the overwhelming majority of infections in the study cohort occurred during the Omicron-dominant period, when the variant itself was generally associated with less severe acute disease. The persistence of measurable psychological and occupational burden under these comparatively favorable conditions suggests that the risk of long-term impairment has been reduced but not eliminated. For the millions of workers globally who have been infected with Omicron-lineage viruses despite vaccination, the Taiwanese data imply that lingering symptoms remain a genuine occupational health concern rather than a relic of earlier pandemic waves.

The authors are careful about what their study can and cannot claim. Because the design is cross-sectional, capturing participants at a single point in time, causal relationships cannot be inferred. It remains possible, for instance, that pre-existing anxiety, poor sleep or low work ability influenced how participants recalled and reported persistent symptoms, rather than the symptoms driving the psychological burden. The non-probability recruitment strategy, while effective for reaching the target population, also limits generalizability; workers who chose to participate in an occupational health study may differ systematically from those who did not. Self-reported symptom status, the standard for long COVID research given the absence of a definitive diagnostic test, introduces additional subjectivity. The researchers openly acknowledge these constraints and call for longitudinal studies to clarify recovery trajectories and functional outcomes over time, which would allow investigators to determine whether reduced work ability precedes, follows or merely co-occurs with post-COVID symptomatology.

Even with those caveats, the study carries practical implications that extend well beyond Taiwan. The authors argue that mental health assessment deserves a central place in post-COVID follow-up care, not as an afterthought but as a routine component of clinical evaluation. This recommendation aligns with a growing body of international evidence linking long COVID to depression, anxiety and sleep disorders, and it reframes post-COVID conditions as a psychosomatic and occupational problem in equal measure with a physical one. For occupational physicians, the message is that a worker presenting with persistent fatigue or brain fog should not only be evaluated for physical sequelae but also screened for insomnia, pandemic-related fear and diminished work capacity. For employers, the findings underscore the value of graded return-to-work programs, workplace accommodations and access to psychological support, since untreated mental health burdens may prolong functional impairment even after physical symptoms begin to subside.

The policy stakes are considerable. Post-COVID conditions affect a substantial fraction of infected individuals worldwide, and because the condition disproportionately impairs the ability to sustain full-time work, its economic ripple effects touch social insurance systems, disability programs and national productivity. Studies conducted in vaccinated, Omicron-era populations are especially valuable for forecasting the forward-looking burden, since they describe the risk profile relevant to new infections rather than historical ones. By demonstrating a 13.9-point quality-of-life deficit and a 3.3-point reduction in work ability under exactly these modern conditions, the Taiwanese study provides quantitative anchors that health economists and policymakers can use to model the ongoing costs of long COVID in the workforce.

The research also highlights the importance of studying long COVID outside the Europe-North America axis, where much of the literature has concentrated. Taiwan’s pandemic trajectory, characterized by early containment followed by a large, late Omicron wave in a highly vaccinated population, offers a distinct natural experiment. The fact that measurable occupational and psychological impairment still emerges in this setting strengthens the argument that post-COVID conditions are a global phenomenon requiring coordinated surveillance, standardized assessment tools and sustained investment in rehabilitation services. The study received no external funding and was approved by the Institutional Review Board of the Chang Gung Medical Foundation, with all participants providing informed consent under protocols compliant with the Declaration of Helsinki.

For now, the study’s central contribution is to quantify, with validated instruments, the invisible toll that persistent post-viral symptoms exact on working adults: poorer perceived health, greater fear, worse sleep and a weakened sense of capacity to meet job demands. As health systems worldwide transition from emergency response to long-term management of COVID-19’s aftermath, evidence of this kind, gathered under the most favorable epidemiological conditions yet seen, serves as a reminder that the pandemic’s occupational and psychological dimensions are far from over. The authors’ call for longitudinal follow-up is the natural next step, and its findings will help determine whether the burdens documented here fade with time or harden into chronic disability for a vulnerable segment of the working population.

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Ebola vaccine research has taken a step toward broader protection against one of the most persistent challenges in filovirus medicine: the existence of multiple Ebola virus species that can cause severe human disease. In a study published in Nature Communications, Weidle, Brunette, Wrenn and colleagues report that a pan-Ebolavirus nanoparticle vaccine protected rodents from lethal infection with both Zaire ebolavirus and Sudan ebolavirus. The finding is significant because vaccines designed around a single viral species may not provide reliable protection against genetically distinct Ebola viruses, particularly those responsible for separate outbreaks in different regions of Africa.

Ebola viruses belong to the filovirus family, a group of filament-shaped, enveloped viruses capable of causing hemorrhagic fever. Zaire ebolavirus is the species most closely associated with the large West African epidemic of 2014–2016 and remains the primary target of licensed Ebola vaccines. Sudan ebolavirus, however, is sufficiently different at the molecular level to present a separate immunological challenge. Outbreaks caused by Sudan virus have repeatedly demonstrated the need for countermeasures that are not limited to one viral lineage. A vaccine capable of recognizing shared features across several Ebola viruses could therefore simplify outbreak preparedness and improve the speed of emergency responses.

The strategy described in the study is based on nanoparticle vaccine technology. Nanoparticles can be engineered to present viral antigens in a highly organized, repetitive arrangement that resembles the dense surface of an actual virus. This geometry can improve the activation of B cells, the immune cells responsible for producing antibodies, by efficiently cross-linking B-cell receptors. Nanoparticles may also enhance the delivery of antigens to lymphoid tissues, where immune responses are initiated and refined. Rather than presenting a soluble protein in a relatively dispersed form, the platform is designed to display Ebola-related molecular targets in a configuration that can stimulate a stronger and more coordinated response.

A central challenge in creating a pan-Ebolavirus vaccine is selecting antigens that are both accessible to the immune system and sufficiently conserved among viral species. Ebola viruses share a broad structural organization, but their surface glycoproteins contain regions that vary in sequence and shape. The glycoprotein is especially important because it enables the virus to attach to host cells and enter them. Antibodies that bind to vulnerable regions of this protein can block infection, interfere with membrane fusion or mark viral particles for destruction by immune cells. A broadly protective vaccine must therefore encourage immunity against sites that remain functionally important even as the virus evolves.

In the rodent experiments, the vaccine was evaluated against lethal challenge with viruses representing the Zaire and Sudan species. Such challenge studies are designed to test whether vaccination-induced immunity can prevent severe disease after exposure to a high-risk pathogen. Protection in this setting reflects the combined activity of several immune mechanisms, including neutralizing antibodies, antibody-dependent cellular functions and virus-specific T-cell responses. Antibodies can prevent viral entry into cells, while T cells and other immune components help eliminate infected cells and limit the spread of infection. The reported protection across both virus species indicates that the nanoparticle formulation generated immune recognition broad enough to cross an important species barrier.

The result does not mean that the viruses are identical, nor does it establish that the vaccine will perform in humans in the same way. Rodent immune systems, dosing schedules and routes of exposure can differ substantially from human conditions. Animal challenge models are nevertheless a crucial stage in vaccine development because they reveal whether an immune response is capable of controlling infection under stringent circumstances. They also allow researchers to examine how quickly protection develops, how long it persists and whether vaccination reduces viral replication and tissue damage. Further studies will be needed to determine which immune markers best predict protection and whether the platform can be adapted for use against additional Ebola species.

The broad scope of the vaccine could have practical implications for epidemic preparedness. Existing Ebola vaccination strategies have demonstrated that immunization can protect against severe disease, but the need to match a vaccine to a particular viral species can complicate decisions during an outbreak. When the causative virus is initially unknown, health authorities may face uncertainty over which product to deploy. A pan-Ebolavirus formulation could potentially reduce that uncertainty by providing coverage against more than one major pathogen. It could also be useful for laboratory personnel, health-care workers and communities living in regions where different Ebola species may emerge over time.

Nanoparticle approaches may offer additional advantages beyond breadth. Their modular design can allow scientists to alter the antigen displayed on the particle without rebuilding the entire vaccine concept from the beginning. This flexibility is relevant to viral pathogens, which can change through mutation and may contain several related species with distinct antigenic profiles. At the same time, the platform must meet demanding standards for manufacturing consistency, stability, storage and safety. A formulation that performs well in laboratory animals must eventually demonstrate reproducible production, acceptable tolerability and durable protection in progressively more advanced models before clinical testing can be considered.

The study’s findings place nanoparticle engineering among the most promising strategies for developing next-generation filovirus vaccines. By combining multivalent antigen presentation with targets shared across Zaire and Sudan viruses, the researchers have demonstrated a route toward broader Ebola protection in rodents. The work does not eliminate the need for species-specific vaccines or replace surveillance, rapid diagnostics and infection-control measures. It does, however, provide experimental evidence that a single vaccine design can generate protective immunity against two medically important Ebola viruses. As outbreaks continue to expose gaps in preparedness, such cross-species technologies could become an important part of the scientific effort to prevent Ebola from turning a local emergence into a global health crisis.

Subject of Research: Pan-Ebolavirus nanoparticle vaccine protection against lethal Zaire and Sudan virus infection in rodents

Article Title: Pan-Ebolavirus nanoparticle vaccine provides protection in rodents from lethal infection by Zaire and Sudan viruses

Article References: Weidle, C., Brunette, N., Wrenn, S.P. et al. Pan-Ebolavirus nanoparticle vaccine provides protection in rodents from lethal infection by Zaire and Sudan viruses. Nature Communications (2026). https://doi.org/10.1038/s41467-026-76114-1

Image Credits: AI Generated

DOI: 10.1038/s41467-026-76114-1

Keywords: Ebola virus, Zaire ebolavirus, Sudan ebolavirus, pan-Ebolavirus vaccine, nanoparticle vaccine, filoviruses, viral immunology, infectious disease, vaccine research, rodent models

Chaque année, un traitement essentiel sauve des millions de jeunes vies. Mais une vaste étude internationale révèle qu’un phénomène inquiétant progresse à un rythme bien plus rapide que prévu, avec des conséquences potentiellement dramatiques d’ici une dizaine d’années. 

Scientists at Imperial College London and The University of Manchester have developed a promising new way to create

Schistosoma mansoni is a parasitic worm that infects millions of people worldwide, entering the body through the skin. Unlike bacterial infections that often cause pain and inflammation, S. mansoni usually slips in unnoticed, rarely causing discomfort. Scientists have long wondered why our skin’s defenses don’t react more strongly to this invader.

Researchers from the University of Pennsylvania and Tulane University explored whether a specialized group of pain-sensing neurons, called TRPV1+, plays a role in detecting and fighting off S. mansoni during its invasion. TRPV1+ neurons are nerve cells in the skin that respond to heat, spicy foods, and certain bacteria and fungi. When activated, they can trigger pain and release molecules that alert the immune system. Previous researchers have shown that these neurons help defend against bacterial and fungal skin infections, but their role in fighting off parasites was unclear. 

To examine how S. mansoni infects its hosts, the team conducted experiments using groups of 4 to 8 mice, matched for age and sex. They repeated each experiment 2 to 3 times to ensure their data was reproducible. They anesthetized the mice, exposed their ears to a solution containing 100 to 150 live S. mansoni larvae, and covered the area with vaseline to keep the solution in place. After 20 to 30 minutes, they counted the number of larvae remaining in the mice’s ears to assess how many had successfully penetrated their skin. 

Next, the team measured pain sensitivity in the mice exposed to the parasite by placing them in chambers and applying an infrared heat source to their paws. They recorded how long it took each mouse to withdraw its paw as a sign of pain. They repeated this test 3 times per paw on each mouse, waited at least 5 minutes between each measurement, and calculated an average withdrawal time. They found that mice infected with S. mansoni were approximately half as sensitive to heat-induced pain as an uninfected control group, suggesting that the parasite could be suppressing the mice’s TRPV1+ neurons.

To investigate this further, the team isolated nerve cells that transmit sensory signals from the mice’s skin, known as dorsal root ganglia, and grew them in the lab. They stimulated these neurons by adding a spicy compound in chili peppers, known as capsaicin. Then they measured calcium influx, a sign the neurons were active, using a special dye that glows differently under a microscope depending on calcium levels. This allowed them to see how active the neurons were and how many molecules they released in response to infection and stimulation. They found that 68% of neurons from uninfected mice responded to capsaicin, but only 26% of neurons from infected mice did so, confirming that the parasite dampened their sensory neuron responses.

To test whether restoring the mice’s neuron activity could help their bodies resist parasite invasion, the researchers genetically engineered the mice to produce a light-sensitive protein in their TRPV1+ neurons, called channelrhodopsin. They “turned on” these neurons by stimulating them with blue light for 30 minutes every day for 5 days before infecting the mice with parasites. Six days later, they assessed the mice’s immune response by using a laser to count immune cells in samples of ear tissue. They also determined how far the parasites had spread by counting larvae in lung samples. They saw that mice with the artificially activated TRPV1+ neurons had nearly double the immune response, blocked roughly twice as many larvae at the skin, and had about 20% fewer parasites in their lungs.

Next, the researchers selectively destroyed TRPV1+ neurons in a new set of mice using a compound known as resiniferatoxin. Three weeks later, they confirmed the treatment had worked by testing the mice’s pain sensitivity using the same heat assay as before. After confirming the mice had lost their pain sensitivity, the team exposed the mice to the parasites. They found that the reinfected mice had 1% to 3% weaker skin immune responses and approximately 25% to 30% more parasites in their lungs than a control group, further confirming that TRPV1+ neurons play a protective role during early infection.

The team concluded that S. mansoni has evolved ways to silence pain-sensing neurons, like TRPV1+. Their discovery suggests that future scientists could boost skin immunity against parasites by targeting sensory neurons. For example, they could develop topical creams or therapies that activate these neurons to help our bodies fight off S. mansoni and similar parasitic invaders.

The post A parasite that numbs your pain appeared first on Sciworthy.

La climatisation ne provoque pas directement un rhume ou une grippe. En revanche, elle peut créer des conditions favorables au développement d’infections. On démêle le vrai du faux.

In an era marked by remarkable advances in antiretroviral therapy (ART), the survival and quality of life of individuals living with HIV have dramatically improved. Yet, new research is now illuminating the complex interplay between immune system dysregulation and the emergence of cardiovascular disease (CVD) in a particularly vulnerable population: adolescents infected with HIV perinatally. A groundbreaking study, published in Nature Communications, spearheaded by Alles, Gunasena, Kettelhut, and colleagues, sheds light on the critical role of natural killer (NK) cell dysfunction in potentiating cardiovascular complications among these young patients, even while on effective ART.

Perinatally acquired HIV represents a unique clinical challenge, as infection occurs during a critical window of immune system development. While ART suppresses viral replication effectively, it does not fully restore immune homeostasis. This dysregulation manifests not only in the persistence of immune activation but also in aberrant immune cell profiles, including those of natural killer cells—a subset of lymphocytes crucial in antiviral defense and immune surveillance. The new findings suggest that disturbances in NK cell function are more than mere epiphenomena; they could actively contribute to the pathogenesis of cardiovascular abnormalities in this patient group.

The study emphasizes that NK cells in adolescents with perinatal HIV exhibit marked phenotypic and functional changes compared to age-matched uninfected controls. These alterations include impaired cytotoxic activity and aberrant expression of activating and inhibitory receptors. Such changes compromise the ability of NK cells to regulate inflammation and eliminate infected or damaged cells, fostering an environment conducive to vascular injury and endothelial dysfunction. This mechanistic insight is critical, as endothelial health is a cornerstone of cardiovascular stability.

By integrating immunophenotyping, functional assays, and clinical cardiovascular assessments, the researchers drew a comprehensive picture linking NK cell abnormalities with early signs of CVD. The adolescents studied demonstrated increased arterial stiffness, altered lipid profiles, and biomarkers indicative of systemic inflammation—all hallmarks of an accelerated atherosclerotic process. Intriguingly, these cardiovascular perturbations persisted despite sustained viral suppression, highlighting that viral load alone cannot explain the heightened cardiovascular risk.

The pathophysiology proposed by the authors centers on a chronic, low-grade inflammatory milieu driven, in part, by dysfunctional NK cell signaling. Typically, NK cells modulate inflammation through cytokine secretion and direct cytolysis of aberrant cells, maintaining tissue homeostasis. However, dysregulated NK cells may either fail to contain inflammatory stimuli or contribute to pathological immune activation. This shift not only exacerbates endothelial dysfunction but may induce vascular remodeling and fibrosis, setting the stage for premature cardiovascular disease.

Molecular analyses revealed upregulation of several pro-inflammatory pathways within NK cells isolated from affected adolescents. Notably, transcriptional profiles highlighted increased expression of genes involved in inflammasome activation, oxidative stress responses, and cell senescence markers—factors strongly implicated in vascular pathology. These insights open avenues for targeted therapeutic interventions aimed at restoring NK cell function and interrupting the inflammatory cascade implicated in CVD progression.

Importantly, the study’s implications go beyond HIV care alone. The concept that immune cell dysfunction can independently drive cardiovascular disease adds a crucial dimension to our understanding of immune-mediated comorbidities. It underscores the necessity of holistic medical care approaches that address the immunological underpinnings of chronic disease states, especially in populations with lifelong exposure to immunological stressors like perinatal HIV.

The findings also raise compelling questions about the adequacy of current ART regimens in mitigating long-term non-AIDS complications. While ART excels at viral suppression, it may not sufficiently address immune reconstitution or the correction of immune cell dysregulation. Future therapeutic strategies might need to incorporate immunomodulatory agents that specifically target NK cell pathways or inflammatory mediators to reduce cardiovascular risk.

Moreover, this study highlights the pressing need for comprehensive cardiovascular screening in adolescents with perinatally acquired HIV. Traditional risk assessment paradigms may not capture the unique pathophysiological mechanisms at play in this population. Early detection of subclinical vascular changes could catalyze timely preventative interventions, potentially improving long-term outcomes.

From a broader perspective, the research invites a re-examination of how chronic infections shape the immune landscape over an individual’s lifespan and influence multisystem disease trajectories. It suggests a paradigm where the immune system’s ongoing attempts to control persistent infection or immunologic insults inadvertently promote collateral tissue damage, exemplified here by cardiovascular impairment.

Technological advances in multi-omics and single-cell profiling have been pivotal in unraveling the nuanced dysfunctions within NK cell subsets elucidated by this work. These tools enable high-resolution mapping of immune cell states and their interactions with the vascular microenvironment, fostering a deeper mechanistic understanding that might have remained elusive with conventional methods.

The involvement of NK cells in this context may also intersect with other immune-mediated pathways, including those involving T cells and monocytes/macrophages, which together orchestrate the inflammatory response underpinning atherosclerosis. Understanding these intricate cellular crosstalk networks will be crucial to designing effective immunotherapies.

In light of this evidence, interdisciplinary collaboration between immunologists, cardiologists, and infectious disease specialists becomes more imperative. Integrating expertise from these domains can accelerate the translation of these findings into clinical interventions that mitigate cardiovascular risk among HIV-infected youth, and perhaps beyond.

Finally, this research presents an urgent call to the global health community to prioritize long-term monitoring and holistic management strategies for adolescents living with perinatal HIV. As their life expectancy approaches normality, addressing comorbid conditions such as cardiovascular disease will be essential to ensuring not just survival but sustained health and quality of life.

In summary, the pioneering study by Alles and colleagues illuminates a previously underappreciated contributor to cardiovascular disease risk in adolescents with perinatally acquired HIV on antiretroviral therapy. The demonstration that NK cell dysregulation may be a key mechanistic driver of early vascular pathology underscores the necessity for innovative therapeutic approaches targeting immune dysfunction beyond viral suppression alone. This work marks a significant advance in understanding the complex interdependencies between chronic viral infection, immune regulation, and cardiovascular health, and sets the stage for transformative changes in clinical practice and research paradigms.

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Subject of Research:
Natural Killer (NK) cell dysfunction and its role in cardiovascular disease development in adolescents with perinatally acquired HIV undergoing antiretroviral therapy.

Article Title:
NK cell dysregulation may potentiate cardiovascular disease in adolescents with perinatally acquired HIV on antiretroviral therapy.

Article References:
Alles, M., Gunasena, M., Kettelhut, A. et al. NK cell dysregulation may potentiate cardiovascular disease in adolescents with perinatally acquired HIV on antiretroviral therapy. Nat Commun (2026). https://doi.org/10.1038/s41467-026-74602-y

Image Credits: AI Generated

A recent clinical investigation into the impact of prone positioning on infants suffering from moderate to severe bronchiolitis has brought new insights into pediatric respiratory care. Bronchiolitis, an acute infection of the lower respiratory tract commonly caused by respiratory syncytial virus (RSV), presents a significant healthcare challenge worldwide, particularly among infants. The study specifically targeted infants receiving high-flow nasal cannula (HFNC) therapy, a common supportive treatment designed to improve oxygenation and reduce respiratory effort. Despite its widespread use, the efficacy of adjunctive positioning techniques like prone positioning in this population has remained uncertain until now.

The trial explored whether placing infants in the prone position—lying on their stomachs—could influence clinical outcomes, specifically by reducing the escalation of care. Escalation of care represents clinical deterioration requiring increased respiratory support, such as moving from HFNC to mechanical ventilation or intensive care admission. The physiological rationale behind prone positioning lies in its known benefits in improving ventilation-perfusion matching, enhancing lung mechanics, and optimizing secretion clearance. These effects have been well-documented in adult acute respiratory distress syndrome (ARDS) management, yet pediatric evidence remains limited.

In the conducted study, infants with moderate to severe bronchiolitis under HFNC support were randomized to receive either prone positioning or continue with standard positioning protocols. Researchers meticulously monitored clinical outcomes, including respiratory parameters, oxygenation indices, and the need for escalating respiratory support over the treatment course. The cohort was carefully selected to include infants representing a range of disease severities, thereby ensuring the findings would be broadly applicable to clinical practice.

Contrary to expectations driven by adult data and mechanistic theories, the results revealed no statistically significant reduction in care escalation rates associated with prone positioning in this infant population. The observed odds ratio exhibited a wide 95% confidence interval, indicating variability and uncertainty around the estimate. This statistical phenomenon suggests that while the study failed to demonstrate definitive benefit, it did not conclusively exclude the possibility that certain subgroups might still derive clinical advantage from this intervention.

The ambiguity exposed by the confidence intervals underscores the complex interplay of factors influencing respiratory mechanics and disease progression in bronchiolitis. The heterogeneity of this disease, rooted in diverse viral etiologies and varying host immune responses, may attenuate the effects of positional changes on lung function. Moreover, compliance with prone positioning protocols can be particularly challenging in infants, owing to safety concerns and caregiver adherence, potentially diluting any therapeutic effect.

Physiologically, the application of high-flow nasal cannula therapy delivers heated and humidified oxygen at flow rates sufficient to generate a mild positive end-expiratory pressure (PEEP), which helps maintain alveolar patency. Prone positioning theoretically complements this by redistributing ventilation, reducing dorsal lung atelectasis, and improving secretion mobilization. However, the dynamic respiratory mechanics of infants, coupled with the distinct pathophysiology of bronchiolitis characterized primarily by airway inflammation and mucus plugging, may limit the translation of these theoretical benefits into clinical outcomes.

In reviewing the methodological aspects, the study was conducted with rigorous adherence to randomized controlled trial protocols. Blinding was implemented where feasible, and standardized clinical criteria dictated escalation of care, thereby minimizing potential biases. The statistical power and sample size calculations accounted for anticipated effect sizes based on previous smaller studies, yet the results accentuated the need for larger, multicentric trials to verify findings and identify responsive patient subsets.

The absence of clear benefit does not diminish the value of prone positioning as a component of critical care but rather refines its role within the therapeutic armamentarium for bronchiolitis. Clinical decisions must integrate a nuanced understanding of individual patient factors, balancing potential physiological advantages against logistical and safety considerations. Additionally, continued research investigating adjunctive therapies, including pharmacologic agents and alternative respiratory support modalities, remains imperative to improve outcomes for this vulnerable population.

This investigation is particularly timely given the ongoing global burden of bronchiolitis and the frequent hospitalization of infants due to severe respiratory distress. Optimizing non-invasive interventions like HFNC and positioning could significantly impact healthcare resource utilization and patient morbidity if proven effective. Until then, prudent clinical judgment guided by evolving evidence must steer treatment approaches.

Future studies should employ advanced imaging and respiratory monitoring techniques such as electrical impedance tomography and lung ultrasound to elucidate the mechanistic effects of prone positioning on infant lung ventilation and perfusion patterns. Stratification by viral etiology, age, and baseline respiratory status could also uncover subpopulations more amenable to positional interventions. Furthermore, integrating caregiver education and safety protocols will enhance feasibility and adherence, potentially amplifying clinical benefits.

In summary, the recent multicenter randomized trial encompassing infants with moderate to severe bronchiolitis on high-flow nasal cannula support indicates that prone positioning does not significantly reduce the risk of escalation of care. Nevertheless, the wide confidence intervals highlight that this evidence is not conclusive, and further meticulously designed research is warranted. Advancing the understanding of respiratory mechanics and therapeutic positioning strategies in bronchiolitis remains a critical priority in pediatric medicine.

Corresponding author Dr. Florent Baudin emphasizes the necessity for ongoing critical appraisal and clinical trials to refine pediatric respiratory care practices. The study’s findings, presented at the International Congress of the European Society of Paediatric and Neonatal Intensive Care, contribute valuable data to the pediatric critical care community. Engaging clinicians, researchers, and healthcare providers in collaborative efforts will be essential to translate these insights into improved outcomes for infants affected by this common yet severe respiratory condition.

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Subject of Research:
Prone positioning effectiveness in infants with moderate to severe bronchiolitis receiving high-flow nasal cannula therapy.

Article Title:
Not provided.

News Publication Date:
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Web References:
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References:
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Image Credits:
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Keywords:
Bronchiolitis, infants, prone positioning, high-flow nasal cannula, respiratory disorders, pediatric intensive care, respiratory support, lung mechanics, clinical research, acute infections, observational studies, medical treatments.

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