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The APPG on Malaria & NTDs gathered on Tuesday, March 19th in Westminster at the Houses of Parliament.
Impact of GLP-1 receptor agonist-induced weight loss on 22 cancers in the next ten years using a Markov state-transition model - A UK weight and wellness cancer landscape analysis.
BACKGROUND: Obesity is a major risk factor for many cancers. Glucagon-like peptide-1 receptor agonists (GLP-1RA) have emerged as highly effective agents for weight loss. There is a lack of published modelling studies describing the broader implications of GLP-1RA-induced weight loss on cancer incidence. METHODS: A Markov state-transition model was devised to evaluate the impact of GLP-1RA-induced weight loss on future cancer incidence in adults. Contemporary data on weight distribution, cancer incidence, and body mass index (BMI)-associated cancer risk were integrated into the model. Two scenarios were assessed, GLP-1RAs were made available to all people with obesity (BMI>30) or only those with severe obesity (BMI>35). New cancer cases were simulated over a decade. RESULTS: Our simulation within a closed cohort indicated that GLP-1RA-induced weight loss would lead to a marked decrease in cancer cases over 10 years in adults. If GLP-1RAs were made available for all people with obesity and 50 % of people with obesity moved into a lower BMI category, there was a simulated reduction in cumulative cancer cases of 21,443. If access to GLP-1RAs was restricted to people with severe obesity and 50 % of people with severe obesity moved into a lower BMI category, there was a simulated reduction in cumulative cancer cases of 7476. This effect was greatest for uterine, kidney, liver and colon cancer. CONCLUSION: Targeted weight control measures using GLP-1RAs could reduce new cancer cases. Based on our models, the potential risk of thyroid cancer is balanced by a reduction in other cancer types. This modelling study shows for the first time that implementing effective weight loss programmes could enhance the health of the population over the next decade through a reduction in cancer cases.
The limitations of mobile phone data for measuring movement patterns of populations at risk of malaria.
BACKGROUND: As global mobile phone adoption increases, mobile phone data has been increasingly used to measure movement patterns of populations at risk of malaria. However, the representativeness of mobile phone data for populations at risk of malaria has not been assessed. This study aimed to assess this representativeness using prospectively collected data on mobile phone ownership and use from malaria patients in Lao PDR. METHODS: A prospective observational study was conducted from 2017 to 2021. 6320 patients with confirmed malaria in 107 health facilities in the five southernmost provinces of Lao PDR were surveyed regarding their demographics, mobile phone ownership and use. Data on the demographics of mobile phone owners and users in the general population of Lao PDR were obtained from the 2017 Lao Social Indicator Survey II, which was a nationally representative survey sample. Descriptive analysis was performed, and logistic regression with weights on aggregate data was used to compare the demographic distribution of mobile phone ownership and use in malaria patients with that in the general population. RESULTS: Most patients with malaria (76%) did not own or use a mobile phone. From 2017 to 2021, mobile phone usage in the general population consistently ranged between 53 and 67%, whereas among malaria patients, usage remained significantly lower, fluctuating between 20 and 28%. At the district level, log malaria incidence rate (API) was weakly negatively correlated with the proportion of mobile owners (R2 = 0.3, p = 0.005). Mobile phone ownership and usage among malaria patients were significantly lower than in the general population (p-value
Unveiling the structural spectrum of SARS-CoV-2 fusion by in situ cryo-ET.
SARS-CoV-2 entry into host cells is mediated by the spike protein, which drives membrane fusion. While cryo-EM reveals stable prefusion and postfusion conformations of the spike, the transient fusion intermediate states during the fusion process remain poorly understood. Here, we design a near-native viral fusion system that recapitulates SARS-CoV-2 entry and use cryo-electron tomography (cryo-ET) to capture fusion intermediates leading to complete fusion. The spike protein undergoes extensive structural rearrangements, progressing through extended, partially folded, and fully folded intermediates prior to fusion-pore formation, a process that depends on protease cleavage and is inhibited by the WS6 S2 antibody. Upon interaction with ACE2 receptor dimer, spikes cluster at membrane interfaces and following S2' cleavage concurrently transition to postfusion conformations encircling the hemifusion and initial fusion pores in a distinct conical arrangement. S2' cleavage is indispensable for advancing fusion intermediates to the fully folded postfusion state, culminating in membrane integration. Subtomogram averaging reveals that the WS6 S2 antibody binds to the spike's stem-helix, crosslinks and clusters prefusion spikes, as well as inhibits refolding of fusion intermediates. These findings elucidate the entire process of spike-mediated fusion and SARS-CoV-2 entry, highlighting the neutralizing mechanism of S2-targeting antibodies.
Unconventional human CD61 pairing with CD103 promotes TCR signaling and antigen-specific T cell cytotoxicity
AbstractCancer remains one of the leading causes of mortality worldwide, leading to increased interest in utilizing immunotherapy strategies for better cancer treatments. In the past decade, CD103+ T cells have been associated with better clinical prognosis in patients with cancer. However, the specific immune mechanisms contributing toward CD103-mediated protective immunity remain unclear. Here, we show an unexpected and transient CD61 expression, which is paired with CD103 at the synaptic microclusters of T cells. CD61 colocalization with the T cell antigen receptor further modulates downstream T cell antigen receptor signaling, improving antitumor cytotoxicity and promoting physiological control of tumor growth. Clinically, the presence of CD61+ tumor-infiltrating T lymphocytes is associated with improved clinical outcomes, mediated through enhanced effector functions and phenotype with limited evidence of cellular exhaustion. In conclusion, this study identified an unconventional and transient CD61 expression and pairing with CD103 on human immune cells, which potentiates a new target for immune-based cellular therapies.
Engineering TCR-controlled fuzzy logic into CAR T cells enhances therapeutic specificity.
Chimeric antigen receptor (CAR) T cell immunotherapy represents a breakthrough in the treatment of hematological malignancies, but poor specificity has limited its applicability to solid tumors. By contrast, natural T cells harboring T cell receptors (TCRs) can discriminate between neoantigen-expressing cancer cells and self-antigen-expressing healthy tissues but have limited potency against tumors. We used a high-throughput platform to systematically evaluate the impact of co-expressing a TCR and CAR on the same CAR T cell. While strong TCR-antigen interactions enhanced CAR activation, weak TCR-antigen interactions actively antagonized their activation. Mathematical modeling captured this TCR-CAR crosstalk in CAR T cells, allowing us to engineer dual TCR/CAR T cells targeting neoantigens (HHATL8F/p53R175H) and human epithelial growth factor receptor 2 (HER2) ligands, respectively. These T cells exhibited superior anti-cancer activity and minimal toxicity against healthy tissue compared with conventional CAR T cells in a humanized solid tumor mouse model. Harnessing pre-existing inhibitory crosstalk between receptors, therefore, paves the way for the design of more precise cancer immunotherapies.
Quantifying biomolecular organisation in membranes with brightness-transit statistics.
Cells crucially rely on the interactions of biomolecules at their plasma membrane to maintain homeostasis. Yet, a methodology to systematically quantify biomolecular organisation, measuring diffusion dynamics and oligomerisation, represents an unmet need. Here, we introduce the brightness-transit statistics (BTS) method based on fluorescence fluctuation spectroscopy and combine information from brightness and transit times to elucidate biomolecular diffusion and oligomerisation in both cell-free in vitro and in vitro systems incorporating living cells. We validate our approach in silico with computer simulations and experimentally using oligomerisation of EGFP tethered to supported lipid bilayers. We apply our pipeline to study the oligomerisation of CD40 ectodomain in vitro and endogenous CD40 on primary B cells. While we find a potential for CD40 to oligomerize in a concentration or ligand depended manner, we do not observe mobile oligomers on B cells. The BTS method combines sensitive analysis, quantification, and intuitive visualisation of dynamic biomolecular organisation.
Comparison of different methods for isolating CD8+ T lymphocyte‐derived extracellular vesicles and supramolecular attack particles
AbstractCD8+ T lymphocytes play vital roles in killing infected or deranged host cells, recruiting innate immune cells, and regulating other aspects of immune responses. Like any other cell, CD8+ T cells also produce extracellular particles. These include extracellular vesicles (EVs) and non‐vesicular extracellular particles (NVEPs). T cell‐derived EVs are proposed to mediate cell‐to‐cell signalling, especially in the context of inflammatory responses, autoimmunity, and infectious diseases. CD8+ T cells also produce supramolecular attack particles (SMAPs), which are in the same size range as EVs and mediate a component of T cell mediated killing. The isolation technique selected will have a profound effect on yield, purity, biochemical properties and function of T cell‐derived particles; making it important to directly compare different approaches. In this study, we compared commonly used techniques (membrane spin filtration, ultracentrifugation, or size exclusion liquid chromatography) to isolate particles from activated human CD8+ T cells and validated our results by single‐particle methods, including nanoparticle tracking analysis, flow cytometry, electron microscopy and super‐resolution microscopy of the purified sample as well as bulk proteomics and lipidomics analyses to evaluate the quality and nature of enriched T cell‐derived particles. Our results show that there is a trade‐off between the yield and the quality of T cell‐derived particles. Furthermore, the protein and lipid composition of the particles is dramatically impacted by the isolation technique applied. We conclude that from the techniques evaluated, size exclusion liquid chromatography offers the highest quality of T cell derived EVs and SMAPs with acceptable yields for compositional and functional studies.
Clathrin mediates both internalization and vesicular release of triggered T cell receptor at the immunological synapse.
Ligation of T cell receptor (TCR) to peptide-MHC (pMHC) complexes initiates signaling leading to T cell activation and TCR ubiquitination. Ubiquitinated TCR is then either internalized by the T cell or released toward the antigen-presenting cell (APC) in extracellular vesicles. How these distinct fates are orchestrated is unknown. Here, we show that clathrin is first recruited to TCR microclusters by HRS and STAM2 to initiate release of TCR in extracellular vesicles through clathrin- and ESCRT-mediated ectocytosis directly from the plasma membrane. Subsequently, EPN1 recruits clathrin to remaining TCR microclusters to enable trans-endocytosis of pMHC-TCR conjugates from the APC. With these results, we demonstrate how clathrin governs bidirectional membrane exchange at the immunological synapse through two topologically opposite processes coordinated by the sequential recruitment of ecto- and endocytic adaptors. This provides a scaffold for direct two-way communication between T cells and APCs.
Androgens Profile in Blood Serum and Follicular Fluid of Women With Poor Ovarian Response During Controlled Ovarian Stimulation Reveals Differences Amongst POSEIDON Stratification Groups: A Pilot Study.
Patients with poor ovarian response (POR) to exogenous gonadotropins stimulation for assisted reproductive technology (ART) have decreased circulating androgens during spontaneous cycles. The Patient-Oriented Strategies Encompassing Individualized Oocyte Number (POSEIDON) is a 4-tier stratification of women with POR to controlled ovarian stimulation (COH) based on age and biomarkers of ovarian reserve has been proposed to maximize the clinical management of this group for ART. The aim of the present study was to characterize the levels of androgens during COH in follicular fluid (FF) and serum in POSEIDON subgroups and compared them with women of normal ovarian response. Sixty nine consecutive patients undergoing ART were included and testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEA-S), estradiol, sex hormone-binding globulin (SHBG), and insulin-like growth factor 1 (IGF-1) were measured in serum and FF collected at the time of oocyte pick-up. The number of retrieved oocytes was registered for each patient for their allocation to the respective POSEIDON subgroup. The control group comprised 19 women and the POSEIDON group 1 (age < 35, normal ovarian reserve biomarkers) n = 14, group 2 (age ≥ 35, normal ovarian reserve biomarkers) n = 8, group 3 (age < 35, poor ovarian reserve biomarkers) n = 6 and group 4 (age ≥ 35, poor ovarian reserve biomarkers) n = 22. Serum levels of total testosterone, androstenedione and DHEA-S were not different in group 1 vs. control but significantly decreased in group 3 vs. control. DHEA-S in FF was also significantly decreased in group 3 vs. control. In addition, serum testosterone was decreased in groups 2 and 4 vs. control; and serum androstenedione and estradiol were reduced in group 4 vs. control. No differences were observed for estradiol, SHBG and IGF-1 in FF. Finally, a high correlation between serum and FF DHEA-S was observed when data from samples of all groups were pooled. Group 1 did not show hypoandrogenemia however group 3 had low levels of all measured androgens in serum and DHEA-S in FF. Such differences might help to better characterize and/or improve the clinical management of women with POR according to their respective POSEIDON stratification.
Percepciones y creencias sobre criopreservación embrionaria en mujeres y hombres que se realizan técnicas de reproducción asistida en Santiago, Chile.
Background and objetiveAlthough embryo cryopreservation is frequently used as part of assisted reproductive technology, quantitave information addressing how infertile couples live the experience of having cryopreserved embryos is lacking in Chile. The aim of this study is to examine men and women's perception and beliefs regarding their cryopreserved embryos, as well as their perspective on embryo donation and disposition. Methods: 153 women and men with frozen embryos from a public hospital, Instituto de Investigactiones Materno Infantil, and a private clinic, Clínica Las Condes, in Santiago, Chile, responded between May 2015 and May 2016 to an anonymous online survey addressing their perceptions and beliefs concerning their cryopreserved embryos.ResultsRespondents considered their frozen embryos to be equivalent to a child (53.2%) or a potential child (40.7%). Only 8% regard them as an organized group of cells. Over 60% of respondents disagree with destroying surplus embryos or using them for research. Participants from the public hospital are more willing to donate their embryos to another couple than those from the private center (61% vs 40%; P=0.016); 34% of respondents agreed to donate surplus embryos to same sex couples.ConclusionThis study reveals that Chilean couples are emotionally bound to their frozen embryos, and that discarding them is not an option. The results from this survey will help strengthen counseling for couples to enable them to make informed decisions regarding their surplus embryos.
[Prevalence of endometriosis in 287 women undergoing surgical sterilization in Santiago Chile].
BackgroundThe clinical manifestations of endometriosis are infertility, dysmenorrhea, sexuality disturbances, and chronic pelvic pain. It is the cause of 30 to 50% of infertility cases. In developed countries, the prevalence of endometriosis among women undergoing surgical sterilization is approximately 6%.AimTo determine the prevalence of endometriosis among women with proven fertility in Santiago de Chile.Material and methodsReview of surgical protocols of 287 women aged 25 to 49 years, subjected to a surgical sterilization between 2007 and 2011.ResultsEndometriosis was found in 14 of the 287 women (4.9%). In spite of being asymptomatic, five of the 14 women with endometriosis were classified as severe, due to the presence of at least one endometrioma. In order of frequency, the most commonly affected anatomical sites were the ovary, the peritoneum, the posterior cul-de-sac and uterosacral ligaments.ConclusionsOur findings are very similar to those found elsewhere and suggest that fertile women could better tolerate endometriosis than their infertile counterparts.
[Effects of smoking on plasma antimüllerian hormone concentrations among infertile women].
BackgroundSmoking may hamper female fertility, probably modifying ovarian reserve. Antimüllerian hormone (AMH) is an accurate marker for ovarian reserve.AimTo look for an association between smoking status and plasma AMH concentration.Patients and methodsA cohort of 141 infertile women in a university setting in Santiago, Chile was studied. Demographic and smoking data, including the number of cigarettes smoked during the last week, were collected. A blood sample was obtained and kept frozen until determination of AMH by ELISA and follicle stimulating hormone (FSH) and estradiol at day three of the menstrual cycle, by radioimmunoanalysis.ResultsThirty two participants smoked (23%). There were no significant differences in age, parity, body mass index, causes of infertility and day three FSH and estradiol between smokers and nonsmokers. According to a regression analysis, there was a significant decrease in AMH concentration with age and active cigarette smoking. A drop in AMH of -0.189 ng/mL with a unitary change in age and a decrease of -2.29 ng/mL when everything else remains constant, except the smoking status, were established (p < 0.001 and r2 = 0.134). However, no dose response was observed when the number of cigarettes smoked during the last week were introduced in the model. Furthermore, no significant association of plasma AMH with day three plasma FSH and estradiol concentrations was observed.ConclusionsCigarette smoking is associated with decreased AMH plasma concentrations among infertile women. However there was no dose response relationship. The mechanisms underlying this association are unknown and further investigation is required.
Epithelial GREMLIN1 disrupts intestinal epithelial-mesenchymal crosstalk to induce a wnt-dependent ectopic stem cell niche through stromal remodelling.
In homeostasis, counterbalanced morphogen signalling gradients along the vertical axis of the intestinal mucosa regulate the fate and function of epithelial and stromal cell compartments. Here, we use a disease-positioned mouse and human tissue to explore the consequences of pathological BMP signalling dysregulation on epithelial-mesenchymal interaction. Aberrant pan-epithelial expression of the secreted BMP antagonist Grem1 results in ectopic crypt formation, with lineage tracing demonstrating the presence of Lgr5(-) stem/progenitor cells. Isolated epithelial cell Grem1 expression has no effect on individual cell fate, indicating an intercompartmental impact of mucosal-wide BMP antagonism. Treatment with an anti-Grem1 antibody abrogates the polyposis phenotype, and triangulation of specific pathway inhibitors defines a pathological sequence of events, with Wnt-ligand-dependent ectopic stem cell niches forming through stromal remodelling following BMP disruption. These data support an emerging co-evolutionary model of intestinal cell compartmentalisation based on bidirectional regulation of epithelial-mesenchymal cell fate and function.
An RBD-Fc mucosal vaccine provides variant-proof protection against SARS-CoV-2 in mice and hamsters.
Current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are effective against severe disease and death, but do not prevent viral infections, probably due to the limited mucosal immunity induced by intramuscular administration of the vaccine. Fusion of SARS-CoV-2 subunit immunogens with a human IgG Fc backbone can be used as a mucosal vaccine but its effectiveness in delivery in animal models, and its immunogenicity and the vaccine-induced protection against viral infections requires further studies. Here we investigate a bivalent RBD-Fc vaccine that includes the spike receptor-binding domains (RBDs) of the ancestral and BQ.1.1 variant of SARS-CoV-2. Ex vivo fluorescent imaging demonstrates that this vaccine can be effectively delivered to the lungs of mice through intranasal administration, with enhancement of retention in the nasal cavity and lung parenchyma. In mice, the vaccine elicited potent and broad-spectrum antibody responses against different variants including KP.3 which could persist for at least 3 months after booster. Importantly, it was able to induce RBD-specific mucosal IgA responses. Further, heterologous intranasal immunisation with adeno-vectored Chadv1 and RBD-Fc elicited both potent neutralising antibody and T cell responses. Immunised BALB/c and K18-hACE2-transgenic mice were also protected against viral challenge of XBB.1 and viral transmission was effectively limited in hamsters through intranasal immunisation. This work thus demonstrates the potential of RBD-Fc antigens as mucosal vaccines for prevention of breakthrough infections and onward transmission. Moreover, Fc-fusion proteins can be used as an effective mucosal vaccine strategy which can be used either alone or in combination with other vaccine technology to constitute heterologous immunisations, enabling strong protection against SARS-CoV-2 and other respiratory viruses.
Detection of Mycoplasma pneumoniae in hospitalized children with pneumonia in Laos
Mycoplasma pneumoniae has been described worldwide as an important cause of community-acquired pneumonia. From December 2013 to December 2014, 461 children admitted to Mahosot Hospital, Vientiane, Laos, with acute respiratory infection were investigated for upper respiratory microorganisms using probe-based real-time polymerase chain reaction (PCR) (FTD33). M. pneumoniae was detected by FTD33 in the upper respiratory tract of three patients, two girls and one boy, 5.7 and 3.9 years old and 13.6 years old, respectively. They presented with clinical features compatible with M. pneumoniae infection. They improved without M. pneumoniae directed therapy. The two girls were also positive for other potential pathogens. The boy had abnormal pulmonary auscultation, and one of the girls had significant anaemia. These results suggest that enhancement of diagnostic systems for M. pneumoniae detection is needed to improve understanding of the epidemiology of M. pneumoniae infection in Laos.
Effect of a Laparoscopic Donor Nephrectomy in Healthy Living Kidney Donors on the Acute Phase Response Using Either Propofol or Sevoflurane Anesthesia
Surgical trauma elicits a complex inflammatory stress response, contributing to postoperative morbidity and recovery variability. This response is influenced by patient-specific factors and surgical and anesthetic techniques. To isolate the impact of anesthesia on the acute phase response, we investigated plasma proteomic changes in a uniquely homogeneous cohort of healthy, living kidney donors (n = 36; propofol = 19; sevoflurane = 17) undergoing laparoscopic donor nephrectomy. Proteomic profiling of plasma samples collected preoperatively and at 2 and 24 h postoperatively revealed 633 quantifiable proteins, of which 22 showed significant perioperative expression changes. Eight proteins exhibited over two-fold increases, primarily related to the acute phase response (CRP, SAA1, SAA2, LBP), tissue repair (FGL1, A2GL), and anti-inflammatory regulation (AACT). These changes were largely independent of anesthetic type, though SAA2 and MAN1A1 showed anesthetic-specific expression. The upregulation of these proteins implicates the activation of immune pathways involved in host defense, tissue remodeling, and inflammation resolution. Our findings provide a molecular reference for the surgical stress response in healthy individuals and highlight candidate biomarkers for predicting and managing postoperative outcomes. Understanding these pathways may support the development of strategies to mitigate surgical stress and enhance recovery, particularly in vulnerable patient populations.
Efficacy of artemisinin-based combination therapy (ACT) in people living with HIV (PLHIV) diagnosed with uncomplicated Plasmodium falciparum malaria in Africa: a WWARN systematic review.
BackgroundAfrica bears the highest double burden of HIV and malaria worldwide. In 2023, an estimated 25.9 million people were living with HIV (PLHIV), and 246 million malaria cases were diagnosed in Africa. Malaria patients co-infected with HIV are considered at a higher risk of failing malaria treatment, according to the World Health Organization (WHO) guidelines. This systematic literature review aims to assess the treatment outcomes following artemisinin-based combination therapy (ACT) in PLHIV.MethodsThe literature search was conducted up to April 2022 in the following databases: MEDLINE, EMBASE, Web of Science, Cochrane Central, WHO Global Index Medicus, Clinicaltrials.gov, and the WorldWide Antimalarial Resistance Network (WWARN) Clinical Trial Library. Studies describing any malaria treatment outcomes or anti-malarial drug exposure in PLHIV treated for uncomplicated Plasmodium falciparum malaria infection were eligible for inclusion.ResultsA total of 26 articles describing 19 studies conducted between 2003 and 2017 in six countries were included in this review; it represented 2850 malaria episodes in PLHIV across various transmission settings. The most studied artemisinin-based combination was artemether-lumefantrine (in 16 studies). PLHIV were treated with various antiretroviral therapy (ART) regimens, namely efavirenz (EFV), nevirapine (NVP), atazanavir-ritonavir (ATVr), lopinavir-ritonavir (LPV/r), and/or on prophylaxis with trimethoprim-sulfamethoxazole (TS), or were untreated (in 3 studies). There was no evidence of an increased risk of recrudescence in PLHIV compared to those without HIV. When treated with artemether-lumefantrine, PLHIV receiving LPV/r had a lower risk of malaria recurrence compared to PLHIV on NVP-based or EFV-based ART, or those without HIV. LPV/r increased lumefantrine exposure and EFV-treated patients had a reduced exposure to both artemether and lumefantrine; NVP reduced artemether exposure only.ConclusionsLimited data on ACT outcomes or drug exposure in PLHIV in Africa remains a reality to date, and the effect of antivirals appears inconsistent in the literature. Considering the heterogeneity in study designs, these review's findings support conducting an individual patient data meta-analysis to explore the impact of antiretroviral therapy on anti-malarial treatment.Trial registrationThe protocol for the original search was published on PROSPERO with registration number CRD42018089860.
CD4+ tissue-resident memory Th17 cells are a major source of IL-17A in Spondyloarthritis synovial tissue.
OBJECTIVES: Interleukin (IL)-17A is a key driver of spondyloarthritis (SpA) joint pathology. We aimed to identify its cellular source in synovial tissue from patients with 2 forms of SpA, namely axial SpA (AxSpA) and psoriatic arthritis (PsA). METHODS: Synovial tissue from patients with SpA was profiled using single-cell RNA sequencing (scRNA-seq; AxSpA, n = 5; PsA, n = 6) or spatial RNA profiling (PsA, n = 4). CellPhoneDB was used to infer cell-cell communication. Tissue-resident memory Th17 (TRM17)-like cells were generated in vitro using blood memory CD4+ T cells from SpA patients. An epigenetic inhibitor library, siRNA, and clustered regularly interspaced short palindromic repeats (CRISPR) were used to identify epigenetic regulator(s) for TRM17. RESULTS: scRNA-seq showed that CD4+CXCR6+ TRM17 cells are the predominant spontaneous IL17A producers in SpA synovium. Cell-cell communication and single-cell spatial analysis support the interaction between TRM17 and CLEC10A+ dendritic cells, which were activated in SpA. Both sublining and lining fibroblasts in SpA synovium showed evidence of interleukin (IL)-17A activation. In vitro-generated CD4+ TRM17-like cells phenocopied joint tissue TRM17, producing IL-17A/F upon T cell-receptor (TCR) stimulation, which was further enhanced by cytokines. Perturbation of BRD1 inhibited the generation of TRM17-like cells. CONCLUSIONS: CD4+ TRM17 cells are the predominant source of IL-17A in SpA synovial tissue. TCR stimulation is essential for the secretion of IL-17A by CD4+TRM17-like cells. The epigenetic regulator bromodomain-containing protein 1 (BRD1) contributes to the generation of CD4+TRM17. Depleting CD4+TRM17 cells in SpA is thus a therapeutic strategy with potential to induce long-term remission.