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Microbiome. 2025 Feb 28;13(1):61. doi: 10.1186/s40168-025-02050-9.

ABSTRACT

BACKGROUND: Promoting resistance to enteric pathogen infection is a core function of the gut microbiota; however, many of the specific host-commensal interactions that mediate this protection remain uncharacterised. To address this knowledge gap, we monocolonised germ-free mice with mouse-derived commensal microbes to screen for microbiota-induced resistance to Salmonella Typhimurium infection.

RESULTS: We identified Enterocloster clostridioformis as a protective species against S. Typhimurium infection. E. clostridioformis selectively upregulates resistin-like molecule β and cell cycle pathway expression at the level of caecal epithelial cells and increases T-regulatory cells in the underlying mucosal immune system, potentially contributing to reduced infection-induced pathology.

CONCLUSIONS: We highlight novel mechanisms of host-microbe interactions that can mediate microbiota-induced resistance to acute salmonellosis. In the backdrop of increasing antibiotic resistance, this study identifies novel potential avenues for further research into protective host responses against enteric infections and could lead to new therapeutic approaches. Video Abstract.

PMID:40022210 | DOI:10.1186/s40168-025-02050-9

Front Immunol. 2025 Feb 12;16:1561850. doi: 10.3389/fimmu.2025.1561850. eCollection 2025.

ABSTRACT

[This corrects the article DOI: 10.3389/fimmu.2022.1039765.].

PMID:40013135 | PMC:PMC11862822 | DOI:10.3389/fimmu.2025.1561850

Nat Cardiovasc Res. 2025 Feb 24. doi: 10.1038/s44161-025-00612-6. Online ahead of print.

ABSTRACT

Myocarditis, characterized by inflammatory cell infiltration, can have multiple etiologies, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or, rarely, mRNA-based coronavirus disease 2019 (COVID-19) vaccination. The underlying cellular and molecular mechanisms remain poorly understood. In this study, we performed single-nucleus RNA sequencing on left ventricular endomyocardial biopsies from patients with myocarditis unrelated to COVID-19 (Non-COVID-19), after SARS-CoV-2 infection (Post-COVID-19) and after COVID-19 vaccination (Post-Vaccination). We identified distinct cytokine expression patterns, with interferon-γ playing a key role in Post-COVID-19, and upregulated IL16 and IL18 expression serving as a hallmark of Post-Vaccination myocarditis. Although myeloid responses were similar across all groups, the Post-Vaccination group showed a higher proportion of CD4+ T cells, and the Post-COVID-19 group exhibited an expansion of cytotoxic CD8+ T and natural killer cells. Endothelial cells showed gene expression changes indicative of vascular barrier dysfunction in the Post-COVID-19 group and ongoing angiogenesis across all groups. These findings highlight shared and distinct mechanisms driving myocarditis in patients with and without a history of SARS-CoV-2 infection or vaccination.

PMID:39994453 | DOI:10.1038/s44161-025-00612-6

bioRxiv [Preprint]. 2025 Feb 5:2025.02.04.636539. doi: 10.1101/2025.02.04.636539.

ABSTRACT

The development of therapies and vaccines targeting integral membrane proteins has been complicated by their extensive hydrophobic surfaces, which can make production and structural characterization difficult. Here we describe a general deep learning-based design approach for solubilizing native membrane proteins while preserving their sequence, fold, and function using genetically encoded de novo protein WRAPs (Water-soluble RFdiffused Amphipathic Proteins) that surround the lipid-interacting hydrophobic surfaces, rendering them stable and water-soluble without the need for detergents. We design WRAPs for both beta-barrel outer membrane and helical multi-pass transmembrane proteins, and show that the solubilized proteins retain the binding and enzymatic functions of the native targets with enhanced stability. Syphilis vaccine development has been hindered by difficulties in characterizing and producing the outer membrane protein antigens; we generated soluble versions of four Treponema pallidum outer membrane beta barrels which are potential syphilis vaccine antigens. A 4.0 Å cryo-EM map of WRAPed TP0698 is closely consistent with the design model. WRAPs should be broadly useful for facilitating biochemical and structural characterization of integral membrane proteins, enabling therapeutic discovery by screening against purified soluble targets, and generating antigenically intact immunogens for vaccine development.

PMID:39975033 | PMC:PMC11838538 | DOI:10.1101/2025.02.04.636539

Drugs. 2025 Mar;85(3):325-341. doi: 10.1007/s40265-024-02143-z. Epub 2025 Feb 19.

ABSTRACT

The complex pathophysiology of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) is reflected in the heterogeneity of the presenting clinical syndromes caused by these diseases but also provides a variety of conceivable molecular and cellular targets that can be therapeutically manipulated. The last decade has seen an expansion of established and potential therapies for treating AAV, some of which target the dysfunctional autoreactive immune response and others aim to ameliorate the downstream consequences of local vascular inflammation and necrosis. The success and widespread adoption of the anti-CD20 monoclonal antibody, rituximab, as an agent to both induce and maintain remission, has heralded a change in the standard-of-care management of AAV, replacing the "old guard" combination of cyclophosphamide and high-dose corticosteroids established in the 1970s. The development and approval of avacopan, a first-in-class small-molecule antagonist to the main receptor for the complement anaphylatoxin C5a, has the potential to reduce the corticosteroid burden experienced by patients with AAV and may also improve outcomes for those with AAV kidney disease. It marks the culmination of almost 20 years of international collaboration, from understanding the pathological role of complement in basic murine models of AAV through to a phase III clinical trial, and emphasises the importance of following promising translational discoveries through to drug development and clinical deployment. This article summarises how recent progress in our understanding of the basic pathophysiology of AAV has resulted in the development of new and effective treatments and, reciprocally, how studying the impact of these treatments in patients has advanced our understanding of dysfunctional immunobiology in disease.

PMID:39969779 | DOI:10.1007/s40265-024-02143-z

iScience. 2025 Jan 16;28(2):111802. doi: 10.1016/j.isci.2025.111802. eCollection 2025 Feb 21.

ABSTRACT

Enteropathogenic infections cause pathophysiological changes in the host but their effects beyond the gastrointestinal tract are undefined. Here, using Citrobacter rodentium infection in mouse, which mimics human diarrheal enteropathogenic Escherichia coli, we show that gastrointestinal infection negatively affects bone remodeling, leading to compromised bone architecture. Transmission of infection through fecal-oral route from Citrobacter rodentium-infected to non-infected mice caused bone loss in non-infected cage mates. Mice with B cell deficiency (Igh6-/- mice) failed to clear C. rodentium infection and exhibited more severe and long-term bone loss compared to WT mice. Unbiased cytokine profiling showed an increase in circulating tumor necrosis factor α (TNFα) levels following Citrobacter rodentium infection, and immunoneutralization of TNFα prevented infection-induced bone loss completely in WT and immunocompromised mice. These findings reveal rapid, relaying, and modifiable effects of enteropathogenic infections on an extraintestinal organ-bone, and provide insights into the mechanism(s) through which these infections affect extraintestinal organ homeostasis.

PMID:39967874 | PMC:PMC11834125 | DOI:10.1016/j.isci.2025.111802

The findings, published today in Science Advances, suggest that such individuals will need regular vaccine boosters to protect them and reduce the risk of infections that could be severe and also lead to new ‘variants of concern’ emerging.

Almost 16 million people worldwide are estimated to have died from Covid-19 during 2020 and 2021, though nearly 20 million deaths are thought to have been prevented as a result of the rapid rollout of vaccines against SARS-CoV-2, the virus that caused the pandemic.

During the pandemic, researchers discovered that immunocompromised individuals had difficulty clearing the virus, even when vaccinated. These are people whose immune systems are not functioning correctly, either as a direct result of disease or because they are on medication to dampen down their immune systems, for example to prevent organ transplant rejection. This meant that their infections lasted longer, giving the virus more opportunities to mutate.

Research from early in the pandemic showed that chronic infections can give rise to variants of concern that can then cause new waves of infection in the wider population.

When an individual is vaccinated, their immune systems produce antibodies that recognise and launch an attack on the virus. Such a process is known as seroconversion. Additional ‘booster’ vaccinations increase seroconversion and hence the likelihood of clearing infection.

However, although most immunocompromised individuals will have received three or more doses of the Covid-19 vaccine, they still account for more than a fifth of hospitalisations, admissions to intensive care units, and overall deaths associated with the disease.

To see why this is the case, scientists at the Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID) at the University of Cambridge examined immunocompromised individuals who had been vaccinated against Covid-19. These patients, recruited from Cambridge University Hospitals NHS Foundation Trust, were living with vasculitis, a group of disorders that cause inflammation of blood vessels. Data from this group was compared against individuals who were not immunocompromised.

Treatments for vasculitis rely on immunosuppressant medicines. These include drugs such as rituximab, which depletes the number of B-cells in the body – but B-cells are the immune cells responsible for producing antibodies. As such, these individuals are a severely at-risk population.

When the researchers analysed bloods samples from the vasculitis patients, they found that even though vaccination induced seroconversion, this in itself was not always sufficient to neutralise the virus. Every immunocompromised individual required at least three doses of the vaccine to protect them across a range of variants up to and include Omicron (the variant that appeared towards the end of 2021 and caused a new wave of infections). In some cases, even four vaccinations were not sufficient to adequately protect them.

Kimia Kamelian, a Gates Cambridge Scholar at CITIID and St Edmund's College, Cambridge, said: “We know that immunocompromised individuals are particularly vulnerable to diseases such as Covid-19 because their immune systems struggle to clear infections. Vaccinations offer some protection, but our study shows that only repeated vaccinations – often four or more – offer the necessary protection.”

Professor Ravi Gupta, also from CITIID and a Fellow at Homerton College, Cambridge, added: “This of course has implications for the individual, who is more likely to have prolonged infection and a much greater risk of severe infection, but it also gives the virus multiple opportunities to mutate.

“We know from our previous work that at least some of the variants of concern probably emerged during chronic infections. That’s why these individuals must be given priority for updated vaccines against new variants.”

The research was funded by Wellcome, Gates Cambridge, Addenbrooke’s Charitable Trust and Vasculitis UK, with additional support by the National Institute for Health and Care Research Cambridge Biomedical Research Centre.

Reference
Kamelian, K et al. Humoral responses to SARS-CoV-2 vaccine in vasculitis-related immune suppression. Sci Adv; 12 Feb 2025; DOI: 10.1126/sciadv.adq3342

Vaccinations alone may not be enough to protect people with compromised immune systems from infection, even if the vaccine has generated the production of antibodies, new research from the University of Cambridge has shown.

We know that immunocompromised individuals are particularly vulnerable to diseases such as Covid-19 because their immune systems struggle to clear infectionsKimia KamelianNoSystem imagesVaccination of an senior male

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Sci Adv. 2025 Feb 14;11(7):eadq3342. doi: 10.1126/sciadv.adq3342. Epub 2025 Feb 12.

ABSTRACT

Immune suppression poses a challenge to vaccine immunogenicity. We show that serum antibody neutralization against SARS-CoV-2 Omicron descendants was largely absent post-doses 1 and 2 in individuals with vasculitis treated with rituximab. Detectable and increasing neutralizing titers were observed post-doses 3 and 4, except for XBB. Rituximab in vasculitis exacerbates neutralization deficits over standard immunosuppressive therapy, although impairment resolves over time since dosing. We observed discordance between detectable IgG binding and neutralizing activity specifically in the context of rituximab use, with high proportions of individuals showing reasonable IgG titer but no neutralization. ADCC response was more frequently detectable compared to neutralization in the context of rituximab, indicating that a notable proportion of binding antibodies are non-neutralizing. Therefore, use of rituximab is associated with severe impairment in neutralization against Omicron descendants despite repeated vaccinations, with better preservation of non-neutralizing antibody activity.

PMID:39937891 | DOI:10.1126/sciadv.adq3342

Eur J Immunol. 2025 Feb;55(2):e202451651. doi: 10.1002/eji.202451651.

ABSTRACT

Type I interferon (IFN) signalling induces the expression of several hundred IFN-stimulated genes (ISGs) that provide an unfavourable environment for viral replication. To prevent an overexuberant response and autoinflammatory disease, IFN signalling requires tight control. One critical regulator is the ubiquitin-like protein IFN-stimulated gene 15 (ISG15), evidenced by autoinflammatory disease in patients with inherited ISG15 deficiencies. Current models suggest that ISG15 stabilises ubiquitin-specific peptidase 18 (USP18), a well-established negative regulator of IFN signalling. USP18 also functions as an ISG15-specific peptidase that cleaves ISG15 from ISGylated proteins; however, USP18's catalytic activity is dispensable for controlling IFN signalling. Here, we show that the ISG15-dependent stabilisation of USP18 involves hydrophobic interactions reliant on tryptophan 123 (W123) in ISG15. Nonetheless, while USP18 stabilisation is necessary, it is not sufficient for the regulation of IFN signalling; ISG15 C-terminal mutants with significantly reduced affinity still stabilised USP18, yet the magnitude of signalling resembled ISG15-deficient cells. Hence, USP18 requires non-covalent interactions with the ISG15 C-terminal diGlycine motif to promote its regulatory function. It shows ISG15 is a repressor of type I IFN signalling beyond its role as a USP18 stabiliser.

PMID:39931755 | DOI:10.1002/eji.202451651

Nat Microbiol. 2025 Feb 10. doi: 10.1038/s41564-025-01930-y. Online ahead of print.

ABSTRACT

The gut microbiome modulates immunotherapy treatment responses, and this may explain why immune checkpoint inhibitors, such as anti-PD-1, are only effective in some patients. Previous studies correlated lipopolysaccharide (LPS)-producing gut microbes with poorer prognosis; however, LPS from diverse bacterial species can range from immunostimulatory to inhibitory. Here, by functionally analysing faecal metagenomes from 112 patients with melanoma, we found that a subset of LPS-producing bacteria encoding immunostimulatory hexa-acylated LPS was enriched in microbiomes of clinical responders. In an implanted tumour mouse model of anti-PD-1 treatment, microbiota-derived hexa-acylated LPS was required for effective anti-tumour immune responses, and LPS-binding antibiotics and a small-molecule TLR4 antagonist abolished anti-PD-1 efficacy. Conversely, oral administration of hexa-acylated LPS to mice significantly augmented anti-PD-1-mediated anti-tumour immunity. Penta-acylated LPS did not improve anti-PD-1 efficacy in vivo and inhibited hexa-acylated LPS-induced immune activation in vitro. Microbiome hexa-acylated LPS therefore represents an accessible predictor and potential enhancer of immunotherapy responses.

PMID:39929976 | DOI:10.1038/s41564-025-01930-y

Cell Rep. 2025 Feb 7;44(2):115263. doi: 10.1016/j.celrep.2025.115263. Online ahead of print.

ABSTRACT

Appropriate cellular recognition of viruses is essential for the generation of an effective innate and adaptive immune response. Viral sensors and their downstream signaling components thus provide a crucial first line of host defense. Many of them exhibit subcellular relocalization upon activation, resulting in the expression of interferon and antiviral genes. To comprehensively identify signaling factors, we analyzed protein relocalization on a global scale during viral infection. cAMP-responsive element-binding protein (CREB)-regulated transcription coactivators 2 and 3 (CRTC2/3) exhibited early cytoplasmic-to-nuclear translocation upon infection with multiple viruses in diverse cell types. This movement was dependent on mitochondrial antiviral signaling protein (MAVS), cyclo-oxygenase proteins, and protein kinase A. A key effect of CRTC2/3 translocation is transcription of the fibro-inflammatory cytokine interleukin (IL)-11. This may be important clinically in viral infections associated with fibrosis, including SARS-CoV-2. Nuclear translocation of CRTC2/3 is, therefore, identified as an important pathway in the context of viral infection.

PMID:39921859 | DOI:10.1016/j.celrep.2025.115263

EMBO Rep. 2025 Feb 7. doi: 10.1038/s44319-025-00373-0. Online ahead of print.

ABSTRACT

Cancer driver mutations are defined by their high prevalence in cancers and presumed rarity in normal tissues. However, recent studies show that positive selection in normal epithelia can increase the prevalence of some cancer drivers. To determine their true cancer-driving potential, it is essential to evaluate how frequent these mutations are in normal tissues and what are their phenotypes. Here, we explore the bioavailability of somatic variants by quantifying age-related mutational burdens in normal human colonic epithelium using immunodetection in FFPE samples (N = 181 patients). Positive selection of variants of tumour suppressor genes PTEN and ARID1A associates with monoallelic gene loss as confirmed by CRISPR/Cas9 mutagenesis and changes in their downstream effectors. Comparison of the mutational burden in normal tissue and colorectal cancers allows quantification of cancer driver potency based on relative representation. Additionally, immune exclusion, a cancer hallmark feature, is observed within ARID1A-deficient clones in histologically normal tissue. The behaviour resulting from haploinsufficiency of PTEN and ARID1A demonstrates how somatic mosaicism of tumour suppressors arises and can predispose to cancer initiation.

PMID:39920335 | DOI:10.1038/s44319-025-00373-0

Nat Immunol. 2025 Feb;26(2):215-229. doi: 10.1038/s41590-024-02064-9. Epub 2025 Jan 31.

ABSTRACT

Adaptive immunity is generated in lymphoid organs, but how these structures defend themselves during infection in humans is unknown. The nasal epithelium is a major site of viral entry, with adenoid nasal-associated lymphoid tissue (NALT) generating early adaptive responses. In the present study, using a nasopharyngeal biopsy technique, we investigated longitudinal immune responses in NALT after a viral challenge, using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as a natural experimental model. In acute infection, infiltrating monocytes formed a subepithelial and perifollicular shield, recruiting neutrophil extracellular trap-forming neutrophils, whereas tissue macrophages expressed pro-repair molecules during convalescence to promote the restoration of tissue integrity. Germinal center B cells expressed antiviral transcripts that inversely correlated with fate-defining transcription factors. Among T cells, tissue-resident memory CD8 T cells alone showed clonal expansion and maintained cytotoxic transcriptional programs into convalescence. Together, our study provides unique insights into how human nasal adaptive immune responses are generated and sustained in the face of viral challenge.

PMID:39890933 | DOI:10.1038/s41590-024-02064-9

Thorax. 2025 Mar 18;80(4):255-263. doi: 10.1136/thorax-2024-222596.

ABSTRACT

Acute respiratory distress syndrome (ARDS) is present in >10% of all people admitted to critical care and is associated with severe morbidity and mortality. Despite more than half a century since its first description, no efficacious pharmacological therapies have been developed, and little progress has been made in improving clinical outcomes. Neutrophils are the principal drivers of ARDS, with their priming and subsequent aberrant downstream functions, including interleukin (IL) 1β and IL-18 secretion, central to the disease pathogenesis. The dominant pathways through which IL-1β and IL-18 are believed to be elaborated are multimeric protein structures called inflammasomes that consist of sensor proteins, adaptor proteins and an effector enzyme. The inflammasome's initial activation depends on one of a variety of damage-associated (DAMP) or pathogen-associated (PAMP) molecular patterns. However, once activated, a common downstream inflammatory pathway is initiated regardless of the specific DAMP or PAMP involved. Several inflammasomes exist in humans. The nucleotide-binding domain leucine-rich repeat (NLR) family, pyrin domain-containing 3 (NLRP3), inflammasome is the best described in the context of ARDS and is known to be activated in both infective and sterile cases. The NLR family, caspase activation and recruitment domain-containing 4 (NLRC4) and absent in melanoma 2 (AIM2) inflammasomes have also been implicated in various ARDS settings, as have inflammasome-independent pathways. Further work is required to understand human biology as much of our knowledge is extrapolated from rodent experimental models. Experimental lung injury models have demonstrated beneficial responses to inflammasome, IL-1β and IL-18 blockade. However, findings have yet to be successfully translated into humans with ARDS, likely due to an underappreciation of the central role of the neutrophil inflammasome. A thorough understanding of inflammasome pathways is vital for critical care clinicians and researchers and for the development of beneficial therapies. In this review, we describe the central role of the inflammasome in the development of ARDS and its potential for immunomodulation, highlighting key areas for future research.

PMID:39884849 | DOI:10.1136/thorax-2024-222596

Nat Commun. 2025 Jan 27;16(1):970. doi: 10.1038/s41467-025-55900-3.

ABSTRACT

Gene enhancers often form long-range contacts with promoters, but it remains unclear if the activity of enhancers and their chromosomal contacts are mediated by the same DNA sequences and recruited factors. Here, we study the effects of expression quantitative trait loci (eQTLs) on enhancer activity and promoter contacts in primary monocytes isolated from 34 male individuals. Using eQTL-Capture Hi-C and a Bayesian approach considering both intra- and inter-individual variation, we initially detect 19 eQTLs associated with enhancer-eGene promoter contacts, most of which also associate with enhancer accessibility and activity. Capitalising on these shared effects, we devise a multi-modality Bayesian strategy, identifying 629 "trimodal QTLs" jointly associated with enhancer accessibility, eGene promoter contact, and gene expression. Causal mediation analysis and CRISPR interference reveal causal relationships between these three modalities. Many detected QTLs overlap disease susceptibility loci and influence the predicted binding of myeloid transcription factors, including SPI1, GABPB and STAT3. Additionally, a variant associated with PCK2 promoter contact directly disrupts a CTCF binding motif and impacts promoter insulation from downstream enhancers. Jointly, our findings suggest an inherent genetic coupling of enhancer activity and connectivity in gene expression control relevant to human disease and highlight the regulatory role of genetically determined chromatin boundaries.

PMID:39870618 | DOI:10.1038/s41467-025-55900-3

Lancet. 2025 Jan 25;405(10475):314-328. doi: 10.1016/S0140-6736(24)02560-1.

ABSTRACT

BACKGROUND: In the UK, booster COVID-19 vaccinations have been recommended biannually to people considered immune vulnerable. We investigated, at a population level, whether the absence of detectable anti-SARS-CoV-2 spike protein IgG antibody (anti-S Ab) following three or more vaccinations in immunosuppressed individuals was associated with greater risks of infection and severity of infection.

METHODS: In this prospective cohort study using UK national disease registers, we recruited participants with solid organ transplants (SOTs), rare autoimmune rheumatic diseases (RAIRDs), and lymphoid malignancies. All participants were tested for anti-S Ab using a lateral flow immunoassay, completed a questionnaire on sociodemographic and clinical characteristics, and were followed up for 6 months using linked data from the National Health Service in England. SARS-CoV-2 infection was primarily defined using UK Health Security Agency data and supplemented with hospitalisation and therapeutics data, and hospitalisation due to SARS-CoV-2 was defined as an admission within 14 days of a positive test.

FINDINGS: Between Dec 7, 2021, and June 26, 2022, we recruited 21 575 participants. Anti-S Ab was detected in 6519 (77·0%) of 8466 participants with SOTs, 5594 (85·9%) of 6516 with RAIRDs, and 5227 (79·3%) of 6593 with lymphoid malignancies. COVID-19 infection was recorded in 3907 (18·5%) participants, with 556 requiring a COVID-19-related hospital admission and 17 dying within 28 days of infection. Rates of infection varied by sociodemographic and clinical characteristics but, in adjusted analysis, having detectable anti-S Ab was independently associated with a reduced incidence of infection, with incident rate ratios (IRRs) of 0·69 (95% CI 0·65-0·73) in the SOT cohort, 0·57 (0·49-0·67) in the RAIRD cohort, and 0·62 (0·54-0·71) in the lymphoid malignancy cohort. In adjusted analysis, having detectable anti-S Ab was also associated with a reduced incidence of hospitalisation, with IRRs of 0·40 (0·35-0·46) in the SOT cohort, 0·32 (0·22-0·46) in the RAIRD cohort, and 0·41 (0·29-0·58) in the lymphoid malignancy cohort.

INTERPRETATION: All people with immunosuppression require ongoing access to COVID-19 protection strategies. Assessment of anti-S Ab responses, which can be performed at scale, can identify people with immunosuppression who remain most at risk, providing a mechanism to further individualise protection approaches.

FUNDING: UK Research and Innovation, Kidney Research UK, Blood Cancer UK, Vasculitis UK, and Cystic Fibrosis Trust.

PMID:39863371 | DOI:10.1016/S0140-6736(24)02560-1

Allergy. 2025 Jan 19. doi: 10.1111/all.16472. Online ahead of print.

ABSTRACT

BACKGROUND: Alarmin cytokine IL-25 promotes type 2 inflammatory responses in disorders such as asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) and known targets include ILC2 and Th2 cells. However, other cellular targets for IL-25 remain poorly defined.

OBJECTIVE: To investigate induction and expression of IL-25 receptor (IL-17RB) by B cells and evaluate responsiveness of IL-17RB-expressing B cells to IL-25 in vitro.

METHODS: IL-17RB expression, regulation and function on B cells were evaluated in peripheral blood-derived B cells by flow cytometry and RT-PCR, including in response to IgE-inducing stimuli (anti-CD40 mAb and IL-4). Single-cell RNA sequencing was used to compare IL-17RB+ and IL-17RB-activated peripheral blood-derived B cells. To evaluate B cell IL-17RB expression within type 2 inflamed tissue, B cells were compared from nasal polyps, control turbinate tissue and matched peripheral blood.

RESULTS: Activation of B cells with anti-CD40 and IL-4 increased IL-17RB expression at both protein and mRNA level, which was further upregulated by IL-25. B cells induced to express IL-17RB responded to IL-25 with enhanced antibody production. Single-cell RNA-sequencing showed that IL17RB+ activated B cells expressed higher levels of IGHE, CCL17 and CCL22 compared to IL17RB- B cells. B cells from nasal polyp tissue expressed higher levels of surface IL-17RB compared with control tissue, correlating with patient-reported CRSwNP severity (SNOT-22).

CONCLUSION: Peripheral blood B cells activated under IgE-inducing conditions express surface IL-17RB, and tissue IL-17RB+ B cells are increased in type 2 inflammation. IL-17RB+ cells have a distinct transcriptional profile and respond to IL-25 with enhanced antibody production, highlighting the IL-25/IL-17RB pathway as a potential therapeutic target for CRSwNP and other type 2 inflammatory disorders.

PMID:39829150 | DOI:10.1111/all.16472