Objectives:Despite their anti-cancer properties, natural killer (NK) cells are discarded during CAR T cell manufacturing. NK cells display promising responses as a cell therapy, exhibiting remarkable safety at high doses. Moreover, NK cells have complementary cytokine profiles and distinct antigen-recognition pathways to supplement CAR T cell therapies. We demonstrate parallel expansion of NK cells from the normally discarded PBMC of CAR T cell production for downstream combination therapies against solid and blood-borne malignancies. Methods:CAR T cells were manufactured from buffy coats with initial isolation of T cells from PBMC. NK cells were rapidly expanded in parallel by stimulating the remaining PBMC with membrane-bound (mb)IL-21 + mbIL-15 feeder cells. Expanded NK cells were assessed through spectral flow cytometry and applied as a pretreatment prior to CAR Tcell infusion against xenograft tumor models in NOD-scid IL2Rgammanull (NSG) mice. Results:Applying feeder cells to residual PBMC stimulated 5000-fold expansions of pure NK cells. Expanded NK cells expressed various activation receptors and displayed strong in vitro cytotoxicity, which was further improved in CAR T-conditioned medium. A pretreatment of NK cells enhanced existing CAR T cell therapies, improving in vivo tumor clearance and survival against breast cancer, acute lymphoblastic leukaemia and non-Hodgkin's lymphoma. While NK cells eliminated CD19-/- variants in vitro, they were unable to suppress antigen-escape relapse in vivo. Conclusion:This study encourages the optimal use of leukapheresis product. By recycling discarded PBMC into NK cells, CAR T cell therapies can be effectively enhanced, improving tumor clearance and survival.
Abstract Objectives To evaluate the prognostic value of peripheral immune markers and their static and dynamic changes during different treatment stages in patients with hepatitis B virus (HBV)‐related unresectable hepatocellula carcinoma (uHCC) receiving transarterial chemoembolisation (TACE) combined with immune checkpoint inhibitors (ICIs) and anti‐vascular endothelial growth factor (anti‐VEGF) antibodies or tyrosine kinase inhibitors (TKIs). Methods This single‐centre retrospective study included patients with HBV‐related uHCC treated with TACE combined with ICls and anti‐VEGF antibodies or TKIs between July 2019 and July 2024. Peripheral blood immune indicators were collected at baseline (Cycle 0), the second treatment cycle (Cycle 2) and the fourth treatment cycle (Cycle 4). The primary outcome was overall survival (OS), while secondary outcomes included progression‐free survival (PFS), objective response rate (ORR) and disease control rate (DCR), with tumour response assessed at the first treatment evaluation (at the end of the fourth treatment cycle) based on mRECIST criteria. Longitudinal changes between adjacent time points were calculated (Δ: Cycle 2 ‐ Cycle 0; Δ2: Cycle 4 ‐ Cycle 2). Both static values and dynamic changes in immune markers were subjected to LASSO‐Cox and stepwise multivariate Cox regression analyses to identify independent predictors of OS. Based on the significant variables, a prognostic nomogram and an immune‐based risk score model were developed. To further assess prognostic heterogeneity, patients were stratified by K‐means clustering according to the temporal patterns of the most predictive immune marker, and survival outcomes were compared across the resulting subgroups. Results A total of 67 HBV‐related uHCC patients treated with TACE plus ICIs and anti‐VEGF antibodies/TKIs were included. The cohort had a median follow‐up of 18.2 months, with a median overall survival (mOS) of 30.4 months and a median progression‐free survival (mPFS) of 11.0 months. At the first evaluation, the objective response rate (ORR) was 53.7%, and the disease control rate (DCR) was 86.6%. LASSO‐Cox regression identified several static and dynamic immune markers associated with OS. Ultimately, CD4⁺/CD8⁺ ratio at Cycle 4 (HR = 0.58, p = 0.035), Δ2 NLR (HR = 1.66, p = 0.014), and Δ2 CD3⁺CD4⁺ (HR = 0.04, p = 0.007) were confirmed by stepwise multivariate Cox regression. A prognostic nomogram incorporating these variables demonstrated favourable predictive performance (C‐index = 0.72; AUCs = 0.750, 0.722 and 0.854 for 1‐, 2‐ and 3‐year OS, respectively). The derived immune‐based risk score effectively stratified patients into high‐ and low‐risk groups with significantly different OS (11.5 vs. 34.0 months, p < 0.001) and PFS (7.5 vs. 13.8 months, p = 0.006). The risk score showed a positive correlation with Δ2 NLR (r = 0.50) and negative correlations with CD4⁺/CD8⁺ ratio (r = −0.64) and Δ2 CD3⁺CD4⁺ (r = −0.45). Based on CD3⁺CD4⁺ trajectory clustering, three distinct immune dynamic subtypes were identified, among which the continuous decline group exhibited the poorest prognosis (p = 0.042). Conclusion This study demonstrates the prognostic relevance of peripheral immune markers in patients with HBV‐related uHCC receiving combination therapy. Immune dynamics observed during later treatment stages, rather than baseline measurements, were more strongly associated with overall survival. A risk model based on the CD4⁺/CD8⁺ ratio at Cycle 4, Δ2 NLR and Δ2 CD3⁺CD4⁺ enabled effective prognostic stratification and may provide a useful framework for risk assessment in this patient population.
Abstract Objectives In this case, we present a patient with rapidly progressive unilateral destructive orbital and midface inflammation. Initial detection of Corynebacterium kroppenstedtii was followed by a consistent course of localised necrotizing small‐vessel vasculitis, which was responsive to B‐cell depletion. Methods A 79‐year‐old woman presented with acute left periorbital pain, tearing and purulent discharge. The workup included serial microbiological cultures, fungal and mycobacterial testing, molecular diagnostics, CT/MRI/PET‐CT imaging, multiple surgical biopsies with histopathology and special stains, ANCA testing, and multidisciplinary treatments (antimicrobials, glucocorticoids, methotrexate and rituximab). The clinical course, laboratory work, imaging studies, histological analysis and response to treatment were thoroughly reviewed. Results Initial conjunctival culture revealed C. kroppenstedtii and clindamycin and vancomycin was initiated. Despite escalating antimicrobials, the patient developed progressive inflammation with sinus destruction, cutaneous fistula and cheek abscess, requiring orbital exenteration. The biopsies revealed chronic inflammation with multinucleated giant cells, focal necrosis and small‐vessel vasculitis. ANCA remained negative, and subsequent testing was negative. High‐dose prednisolone improved the patient, prompting the discontinuation of methotrexate because of pancytopenia. Rituximab‐induced remission allowed for steroid tapering and rituximab maintenance, which controlled the disease without complications. Conclusion This case illustrates a rare, localised ANCA‐negative necrotizing small‐vessel vasculitis with destructive orbital involvement and initial detection of C. kroppenstedtii. Although the pathogenic significance of this finding remains uncertain, the case highlights the importance of comprehensive microbiological and immunological evaluation in atypical destructive inflammatory disease. Sustained disease control was achieved with immunosuppressive therapy including rituximab after persistent infection had been excluded.
Abstract Objectives Immunocompromised hosts have reduced immune responses to COVID‐19 vaccination, and more severe disease. Antibody responses correlate with protection but markers of immunity vary across a spectrum of immunocompromise. We compared serologic and cellular responses following Ancestral COVID‐19 vaccines in healthy controls (HC), people with HIV (PWH) and lung transplant (LTx) recipients. Methods Anti‐spike receptor binding domain (RBD) IgG, neutralising antibodies (nAb) and T‐cell responses were assessed one‐month post‐dose 2 and dose 3 of Ancestral COVID‐19 vaccination in HC, PWH and LTx. NAb responses to Ancestral, Delta and Omicron BA.2 and BA.5 variants were assessed. Results Twenty‐nine HC, 21 PWH and 12 LTx recipients were included. PWH demonstrated lower anti‐RBD‐IgG responses (median post‐dose 3: 80.3 μg mL−1 vs 43.3 μg mL−1, P = 0.03) to mRNA COVID‐19 vaccination than HC, while LTx recipients displayed diminished responses following any vaccine (15.3 μg mL−1 vs 74.0 μg mL−1, P = 0.01). Dose 3 increased anti‐RBD‐IgG concentrations and nAb responses in HC and PWH, though Omicron variant neutralisation was attenuated. LTx recipients mounted limited nAb responses. PWH and HC had no difference in nAb responses for Ancestral (median 1738 vs 486.2, P > 0.99) or BA.5 variants (median 34.0 vs 67.9, P > 0.99). Compared with HC, PWH and LTx demonstrated reduced frequencies of SARS‐CoV‐2‐specific memory T cells and a reduced functional memory T‐cell response in LTx. Conclusion Although Dose 3 was beneficial, LTx recipients demonstrated lower serological responses than HC, while reductions were modest in PWH. Immunocompromised groups had reduced but detectable SARS‐CoV‐2‐specific T‐cell responses, demonstrating the utility of COVID‐19 vaccination despite poorer serological responses.
Abstract Objectives Recent outbreak of influenza A/H5N1 viral infections in birds and mammals worldwide prompted renewed concerns over an emerging H5N1‐related influenza pandemic in the generally immunologically‐naive global population. Cross‐reactive CD4+ T cells between A/H1N1 and A/H5N1 subtypes targeting internal and surface influenza proteins have been identified in humans, indicating some protection against severe and fatal A/H5N1 infection. Methods To detect T‐cell responses towards H1 and H5 viruses, we stimulated PBMCs from patients hospitalised with seasonal influenza A viruses, alongside healthy individuals, with overlapping peptide pools spanning hemagglutinin (HA) and neuraminidase (NA) of A/Vietnam/1203/2004 (H5N1) and A/New York/18/2009 (H1N1‐pdm09‐like) viruses. Results Majority of acutely infected and healthy participants (100% and 75%, respectively) had detectable CD4+ and CD8+ T‐cell responses towards H1‐HA and H5‐HA, whereas 30–80% of individuals had detectable H5‐NA responses. H1 and H5 HA‐specific CD4+ T‐cell responses highly correlated, suggesting some level of cross‐reactivity between T‐cell responses directed against H1 and H5 subtypes. HA‐specific CD4+ T‐cell responses were increased in influenza patients compared to healthy participants. We found no differences in H1‐ and H5‐specific T cell responses between those born pre‐ and post‐1968, irrespective of infection status. Sequence alignment of H1 and H5 viruses identified high conservation in the HA2 stalk subunit (81.53%). CD4+ T‐cell immunity towards immunodominant HA306–318 epitope, restricted by several HLA‐DRB1 molecules, revealed limited cross‐reactivity between Group 1 and Group 2 HA‐subtypes. Conclusion We define correlative H1‐ and H5‐specific CD4+ T‐cell responses during seasonal influenza A virus infection, likely reflecting some level of H1/H5 T cell cross‐reactivity.
Abstract Objectives Immune reconstitution following chimeric antigen receptor (CAR)‐T cell therapy remains a critical clinical challenge, and the determinants of natural killer (NK)‐cell recovery are not fully understood. Methods We longitudinally monitored natural killer (NK)‐cell recovery in 64 patients during the first year after CD19‐directed CAR‐T cell therapy, analysing NK‐cell counts and surface receptor expression. Associations between cytokine release syndrome (CRS), cytokine profiles, and NK‐cell numerical reconstitution were evaluated, and mechanistic insights were explored using in vitro NK‐cell assays. Results NK‐cell numerical and phenotypic recovery was impaired within the first month after CAR‐T cell infusion. Notably, NK‐cell numerical recovery was significantly delayed in patients who developed CRS. A reduced NK‐to‐T cell ratio at one‐month post‐infusion was associated with a markedly increased risk of viral infection (hazard ratio = 4.512). Elevated interleukin (IL)‐10 levels during CRS were inversely associated with NK‐cell recovery. Patients with high IL‐10 levels exhibited delayed NK‐cell reconstitution, which was independently validated in two external cohorts. Mechanistically, in vitro exposure of NK cells to IL‐10 promoted caspase‐3 activation, increased apoptosis, and enhanced reactive oxygen species accumulation and lipid peroxidation. Rescue experiments using ferrostatin‐1 and Z‐VAD‐FMK further supported the involvement of IL‐10 in apoptosis and ferroptosis. Conclusion These findings highlight a previously underappreciated role of IL‐10 in shaping NK‐cell reconstitution post‐CAR‐T cell therapy, particularly in the setting of CRS. Patients with CRS accompanied by elevated IL‐10 levels may benefit from anti‐inflammatory interventions or therapeutic strategies aimed at promoting NK‐cell recovery.
We sought to identify determinants of vaccine response in people with multiple sclerosis (pwMS) receiving B‐cell‐depleting therapies. This was a prospective single‐centre cohort study (ACTRN12623001249640). Peripheral blood samples were collected from pwMS receiving ocrelizumab ( n = 38) before and after a third dose of COVID‐19 mRNA vaccine. Immunogenicity was measured by T‐cell IFN‐γ ELISpot, antibody titres and live virus neutralisation. Humoral immunity was benchmarked against pwMS receiving natalizumab ( n = 15), and against a correlate of real‐world protection (50% reduction in incidence of infection). The peripheral immune phenotype was assessed by high‐parameter flow cytometry and tested for association with vaccine response. CD20 + T cells, natural killer (NK) cells and B cells were lower in pwMS receiving ocrelizumab, while CD27 + CD38 + T‐cell and CD8 + NK cell frequencies were elevated relative to natalizumab. Following a third dose, 51% of pwMS on ocrelizumab were seropositive for SARS‐CoV‐2 receptor‐binding domain Ig, and 25% and 14% met the threshold for effective neutralisation of live ancestral and omicron BA.5 virus, respectively. B‐cell frequency at the time of vaccination, but not time since ocrelizumab infusion, positively correlated with antibody response. Immunomodulatory CD56 bright NK cells were negatively associated with antibody response. CD3 − CD20 + B cells (% of lymphocytes) and CD56 bright NK cells (% of NK cells) were associated with effective virus neutralisation in prior non‐responders. Time since ocrelizumab infusion was not associated with protective vaccination. Evaluation of B‐cell and CD56 bright NK cell frequencies may provide a personalised strategy to stratify pwMS for vaccination and prophylaxis.
Abstract Objectives Aicardi‐Goutières syndrome (AGS) is a genetic interferonopathy resulting from defects in nucleic acid metabolism and subsequent enhanced type I interferon signalling. We report how an expedited genomic diagnosis in conjunction with natural history data can enable a long‐term brain‐penetrant anti‐inflammatory regimen to optimise neurodevelopmental outcomes in genetic autoinflammatory brain disorders. Methods Expedited genomic testing identified compound heterozygous ADAR1 mutations. Published natural history data from 33 patients with biallelic ADAR1 mutations reported severe disability (GMFCS V) or death in 79%. To reduce neuroinflammation, we commenced a long‐term pulsed oral dexamethasone protocol (20 mg/m 2 for 3 days every 3 weeks) from the age of 11 months, plus ruxolitinib, a Janus Kinase (JAK) inhibitor (5 mg per day). Results At the age of 24 months, the patient was crawling and walking a few steps unaided, with a GMFCS level of II. Single‐cell RNA sequencing of 41 164 leukocytes, taken before and after 3 months of treatment and compared to three age matched male controls, showed a reversal of upregulated pan‐cellular interferon pathways, with most differentially expressed genes observed in monocytes. On treatment, there was statistically significant downregulation of key autoinflammatory genes, including nucleic acid sensing ( CGAS, IFIH1, SAMHD1 ), interferon‐stimulated genes ( ISG15 and IFIF44L ) and signalling ( JAK1 ). Given the dual immune therapy, it was not possible to define whether the biological effect was related to dexamethasone or JAK inhibitor, or both. Conclusion Compared with natural history data, our data suggest that early diagnosis, and the use of early brain‐penetrant immune suppressants (dexamethasone), may improve outcomes in ADAR1 AGS.
Abstract Objectives T follicular helper (Tfh) cells regulate B‐cell responses within germinal centres primarily via programmed cell death protein 1 (PD‐1) and inducible T‐cell costimulator (ICOS), whereas CXC chemokine receptor type 5 (CXCR5)‐negative T peripheral helper (Tph) cells provide similar support extra‐follicularly. Both subsets contribute to the pathogenesis of acetylcholine receptor‐antibody‐positive myasthenia gravis (AChR‐MG). This study investigated the roles of PD‐1, ICOS and CXCR5 in T‐cell‐mediated B‐cell activation to identify therapeutic targets for MG. Methods CD4 T cells from 10 healthy controls and six untreated AChR‐MG patients were sorted by CXCR5, PD‐1 and ICOS expression, stimulated with anti‐CD3/CD28, and co‐cultured with autologous CD19 B cells. Plasmablast differentiation, total AChR‐IgG and cytokine productions were measured. Results In healthy donors, PD‐1+ or ICOS+ Tph cells modestly enhanced plasmablasts and IgG production, while CXCR5+ Tfh cells co‐expressing PD‐1 or ICOS induced significantly stronger B‐cell responses. In AChR‐MG patients, PD‐1 expressing T cells promoted plasmablasts, antibody production and cytokine secretion regardless of CXCR5, with amplified effects in CXCR5+ co‐cultures. Conclusions PD‐1 expression on CD4+ T cells is associated with increased B‐cell helper capacity. This effect is more pronounced in Tfh‐related contexts and is linked to dysregulated humoral immune responses in MG. PD‐1 appears to play a central role in the pathogenesis of MG, primarily through Tfh cell activity.
Abstract Macrophages of the gastrointestinal system are central regulators of gut development, homeostasis and disease, yet their origin, functional diversification and life stage‐specific roles remain incompletely integrated. This review aimed to provide a comprehensive synthesis of current knowledge on intestinal macrophage ontogeny, heterogeneity and function from prenatal development through adulthood and into the aging phase. We highlight emerging evidence defining embryonic and monocyte‐derived macrophage populations, their specialised roles in tissue remodelling, immune regulation, vascular and neural support, and their dynamic turnover across the lifespan. The review also examines how disruption of key regulatory pathways, including those relating to interleukin 10 (IL10), transforming growth factor (TGFβ) and metabolic signalling, contributes to macrophage dysfunction in inflammatory bowel disease, as an example of a gastrointestinal disorder with macrophage involvement. By integrating findings from lineage‐tracing, single‐cell transcriptomics and functional studies, this review provides a unified framework for understanding intestinal macrophage biology across life stages. This review provides a strengthened understanding of intestinal macrophage biology and establishes a knowledge base for translational therapies that can modify macrophage function to target inflammatory disorders and maintain gut health.
Abstract Objectives To characterise the immune cellular landscape and paired B‐cell and T‐cell receptor repertoires of hypertrophic adenoids in children with obstructive sleep apnoea. Methods We performed 10x Genomics 5′ single‐cell RNA sequencing with paired V(D)J profiling on adenoid tissues from children (AH, n = 4; control, n = 4) and analysed 72 076 high‐quality cells. Results Compared with controls, AH adenoids exhibited an expanded B‐cell compartment (62.26% vs 51.94%, P = 0.029) and a modest increase in plasmacytoid dendritic cells (0.37% vs 0.15%, P = 0.029), accompanied by reduced T‐cell representation (34.19% vs 44.54%, P = 0.029). Within the B‐cell compartment, GC B cell populations were expanded in AH, particularly Cycling B cells (15.07% vs 2.86%, P = 0.029), whereas memory B cells were reduced (21.48% vs 32.18%, P = 0.029). B‐cell receptor analysis demonstrated reduced somatic hypermutation frequencies across multiple mature B‐cell subsets in AH, accompanied by an isotype distribution skewed towards IgM with reduced class‐switched fractions. Although CD8+ tissue‐resident memory T‐cell (TRM) frequencies were similar between groups, CD8+ TRM in AH adenoids displayed interferon‐polarised and antigen‐processing signatures, and T‐cell clonal expansion occurred predominantly within this subset. Conclusion These findings suggest that AH is not merely an anatomic cause of upper airway obstruction but also an immunologically active mucosal state associated with ongoing immune remodelling and antiviral defence.
Abstract Objectives Type 1 diabetes (T1D) is driven by autoreactive T lymphocytes with contributions from innate immune compartments, yet early innate immune alterations associated with autoimmune amplification remain incompletely defined. We aimed at investigating whether circulating innate lymphoid cells (ILCs) contribute to these processes. Methods Circulating ILCs from patients with recent‐onset T1D (n = 12) and age‐matched healthy donors were analysed by spectral flow cytometry and targeted gene‐expression profiling of purified ILC progenitors (ILCP). Metabolic and inflammatory modulation of ILC activation was assessed in vitro. Antigen presentation to autologous memory CD4 T cells was functionally evaluated. Findings were examined across disease progression in NOD mice. Results Total ILC frequencies were comparable between groups; however, ILC1 and ILCP from T1D patients displayed increased activation markers (CD69, HLA‐DR). ILCP exhibited reduced expression of migratory (CCR7, CCR6) and regulatory‐associated genes (ICOS, CD58). Glycolytic inhibition selectively attenuated ILCP activation, supporting a metabolic contribution. IL‐1β, and to a lesser extent IFNγ, enhanced antigen presentation‐associated phenotypes in human circulating ILCs. Upon inflammatory pre‐activation, insulin peptide‐loaded circulating ILCs upregulated MHC class II–associated markers and induced antigen‐specific activation of autologous CD4⁺ memory T cells. NOD mice recapitulated ILC activation and MHC class II expression patterns during diabetes progression. Conclusion Circulating ILCs in recent‐onset T1D display a pre‐activated, metabolically regulated phenotype with functional antigen‐presenting capacity, supporting a potential role in autoimmune amplification. The findings of this exploratory study provide translational insight into innate immune dysregulation associated with recent‐onset T1D.
Abstract Objectives Cancer vaccines combine tumor antigen and adjuvant to drive an anti‐tumor immune response. Clec9A‐targeted nanoparticles directing CD4 and CD8 neo‐epitopes to cross‐presenting dendritic cells (DCs) stimulate adjuvant‐free therapeutically effective tumor‐specific immunity. However, personalised neo‐epitopes limit the scalability of Clec9A nanoparticles for clinical translation. Since Clec9A+ DCs constitutively present relevant neoepitopes in tumors but are suppressed in tumor microenvironments, we developed Clec9A‐targeted STING or RIG‐I liposomes to enhance endogenous tumor immunity. Methods Liposomes encapsulating RIG‐I or the STING agonist MSA‐1 and functionalised with Clec9A binding peptide WH were optimised for uptake by Clec9A+ conventional and plasmacytoid DCs in vivo. Biodistribution after i.v. administration was determined with in vivo imaging and cellular uptake and activation with flow cytometry. Plasma was analysed for type 1 interferon (IFN) by ELISA and liver, spleen, tumor, blood, kidney, heart and tumor draining lymph node transcriptomes were analysed with Nanostring. Effects on tumor growth and survival, and tumor‐specific T cells were evaluated using the B16 melanoma model. Results Clec9A‐targeting liposomes administered i.v. were distributed to spleen, liver and tumor and were taken up by cross‐presenting and plasmacytoid DCs. Type 1 IFN production and DC, B‐ and T‐cell activation were more effective with i.v. Clec9A‐STING than Clec9A‐RIG‐I liposomes. Intravenous Clec9A‐STING liposomes stimulated IFN‐dependent transcription in blood, lung, tumor, and draining lymph nodes. Intravenous Clec9A‐STING liposomes, or intra‐tumoral Clec9A‐RIG‐I liposomes significantly suppressed B16‐F10 melanoma growth and induced neo‐epitope and survivin‐specific CD4+ and CD8+ T‐cell responses. Conclusions Clec9A‐STING liposomes are a scalable, translatable tumor‐targeted immunotherapy platform.
Objectives:Refractory celiac disease type II (RCDII) is an intestinal tumor of aberrant intra-epithelial T-lymphocytes (IEL). The severe enteropathy found in RCDII is caused by aberrant IEL that exert cytotoxicity against enterocytes. In this study, we investigated the cell death mechanism responsible for villous atrophy in RCDII. Methods:Aberrant IEL were isolated from duodenal biopsies of RCDII patients. Enterocyte and RCDII patient-derived cell lines and human small intestinal organoids were used. mRNA expression was determined with reverse transcriptase-multiplex ligation-dependent probe amplification. Protein expression, degranulation and enterocyte killing were measured using flow cytometry, immunofluorescence or bright field microscopy. Secretion of granzyme-B was detected by enzyme immunoassay. Results:Levels of granzyme-B expression were significantly upregulated in aberrant IEL of RCDII patients compared to patients with celiac disease (CD) on gluten-free diet (P = 0.0001) and correlated with severity of villous atrophy and clinical response to therapy. Killing of intestinal epithelial cells was caused by granzyme-B. For granzyme-B degranulation and subsequent cytotoxicity, cell-cell binding via the CD103-receptor, which was upregulated on aberrant IEL, was essential. In a preclinical model, aberrant IEL migrated to the intestinal organoids and induced organoid disintegration and CD103-dependent cell death. Targeting CD103-heterodimeric partner β7 with therapeutic monoclonal antibody etrolizumab prevented enterocyte cell killing and resulted in survival of organoids. Conclusion:Killing of enterocytes in RCDII patients depends on degranulation of granzyme-B by aberrant IEL through CD103-β7 binding. By blocking this interaction, etrolizumab restores the intestinal epithelium and therefore should be considered as potential therapy for RCDII patients.
Objectives:Gamma-delta (γδ) T cells have been associated with favorable prognoses across several malignancies, underscoring their potential as targets for novel immunotherapies. These unconventional T lymphocytes exhibit an intrinsic tropism for the tumor microenvironment, largely driven by their capacity to recognize stress-induced antigens characteristic of metabolically dysregulated tumors. Unlike the mechanism governing conventional cytotoxic CD8+ alpha-beta (αβ) T cells, γδ T-cell receptors can engage tumor cell moieties independent of major histocompatibility complex class-I (MHC-I) and human leukocyte class-I molecules. Therefore, γδ T cells may have a pivotal role in the immune response to beta-2 microglobulin-mutated MHC-I negative (MHC-I-) colorectal cancers (CRCs) with deficient mismatch repair. Methods:To determine whether γδ T-cell mobilisation extends to diverse aetiologies of MHC-I loss, we used multispectral immunohistochemistry to stain 150 stage I-IV primary CRC tissues, across eight tissue microarrays. Results:Our investigation revealed MHC-I loss in ~30% of CRC primary tumors across all disease stages, with a notable increase in stromal γδ T-cell frequency and activation status among stage III cases. Importantly, these findings extend previous observations largely confined to mismatch repair-deficient CRC by demonstrating that stromal γδ T-cell enrichment associated with MHC-I loss also occurs in mismatch repair-proficient tumors, suggesting a broader role for γδ T cells in immune surveillance of MHC-I-deficient CRC. Conclusion:These data highlight the potential of γδ T cells in counteracting immune evasive MHC-I- tumors, thereby offering a robust rationale for their strategic deployment in next-generation immunotherapy regimens.
Objectives:The anti-PD-L1 antibody avelumab has demonstrated efficacy across multiple cancer types. Avelumab primarily blocks the PD-1/L1 immune checkpoint, while inducing antibody-dependent cellular cytotoxicity (ADCC) from CD16a+ NK cells. However, subsets of patients possess lower-affinity CD16a allotypes that limit ADCC capacity of monoclonal antibodies. In this study, we modified the Fc domain of avelumab with characterised mutations to enhance ADCC across all CD16a allotypes. Methods:Comparisons between the wild-type avelumab and modified 'AveFc5M' were carried out to assess the impacts of introduced mutations on PD-L1 blockade, ADCC induction and complement-dependent cytotoxicity (CDC) induction. To assess ADCC, a range of PD-L1+ target cells were coated with mab prior to incubation with effector cells, with both high- and low-affinity CD16a allotypes represented. Human serum was employed for assessing CDC. Results:Both antibodies exhibited equivalent PD-L1 blocking activity. Notably, the modified AveFc5M displayed significantly enhanced ADCC across diverse tumor cell-effector cell combinations. Fc mutations also conferred the ability to mediate complement-dependent cytotoxicity (CDC) against a PD-L1+ lymphoma cell line. However, short term activation of NK cells or long-term expansion on artificial antigen presenting cells, led to upregulation of PD-L1 on NK cells. Addition of avelumab or AveFc5M to these NK cell populations induced a marked reduction in viable NK cells via ADCC-mediated fratricide. Conclusion:These findings demonstrate that Fc engineering of avelumab can substantially augment ADCC and CDC activity against PD-L1+ tumors. However, the enhanced effector function of AveFc5M led to NK cell fratricide, potentially limiting NK cell-dominated anti-cancer responses.
Abstract Gastric polyps are a heterogeneous group of mucosal lesions increasingly detected during routine endoscopy, encompassing entities with distinct pathogenesis, immune landscapes and variable malignant potential. Accumulating evidence highlights the central role of gastric mucosal immunity in driving polyp initiation, progression, and, in select subtypes, neoplastic transformation. This review synthesises current knowledge on the immunopathogenesis of major gastric polyp subtypes, including hyperplastic, fundic gland, adenomatous, neuroendocrine and inflammatory fibroid polyps, with a particular emphasis on the interplay between chronic inflammation, epithelial injury and immune‐mediated tissue remodelling. We discuss how Helicobacter pylori infection, autoimmune gastritis, proton pump inhibitor–induced hypergastrinemia and genetic syndromes shape distinct immune microenvironments characterised by specific cytokine profiles, immune cell infiltrates and epithelial responses. Special attention is given to mechanisms linking sustained immune activation to dysplasia and carcinogenesis, including oxidative stress, cytokine‐driven proliferation, immune surveillance failure and early engagement of immune checkpoint pathways such as PD‐1/PD‐L1. Furthermore, we explore emerging diagnostic, prognostic and therapeutic implications of immune profiling in gastric polyps, ranging from H. pylori eradication and chemoprevention to the potential role of immunomodulatory strategies in high‐risk lesions. By integrating immunology with histopathology and clinical behaviour, this review provides a comprehensive framework for understanding gastric polyp biology and identifies key gaps and future directions for precision surveillance and immune‐targeted prevention of gastric neoplasia.
Abstract Objectives Vitiligo is an autoimmune disorder characterised by the presence of depigmented lesions on the skin. The autoreactive cytotoxic T cells at the epidermal‐dermal junction of the skin facilitate the targeted destruction of epidermal melanocytes, leading to the development of vitiligo lesions. Narrow‐band UVB (NBUVB) phototherapy is a widely used non‐invasive treatment that promotes transient repigmentation of lesions. However, the specific effects of NBUVB on skin dermal T cells in vitiligo patients remain largely unexplored. Insights into the mechanism of action of NBUVB phototherapy can guide therapies against cytotoxic T cells, enabling effective and sustained remission of vitiligo lesions. Methods Indian patients with active vitiligo lesions underwent 3 months of NBUVB phototherapy, thereby leading to successful repigmentation of vitiligo lesions. Spatial transcriptomic and histological analyses were employed to investigate the gene expression profiles of dermal T cells at the epidermal‐dermal junction, both before and after treatment. Results Comprehensive spatial transcriptome analysis of skin dermal T cells revealed that NBUVB phototherapy leads to the overall suppression of inflammatory genes and immune regulatory pathways that are upregulated in vitiligo patients before treatment. Consequently, tissue‐resident innate and adaptive immune cells significantly decrease post‐UVB phototherapy. Interestingly, we observe an increase in naïve CD4+ T cells post‐UVB phototherapy. Conclusion NBUVB phototherapy effectively suppresses the innate and adaptive immune cell populations and immune regulatory pathways while promoting an increase in naïve CD4+ T cells. These findings underscore a previously unrecognised immunomodulatory role of NBUVB phototherapy in vitiligo patients.
Objectives:To assess neutralizing antibody responses to emerging SARS-CoV-2 variants. Methods:We explored SARS-CoV-2 neutralizing antibodies in140 adults participating in a longitudinal study of antibody responses to COVID vaccines. Participants reported monthly on vaccine doses, and SARS-CoV-2 infections. Serum was collected in December 2023 and April 2024 to determine neutralizing antibody to Wuhan ancestral strain and Omicron XBB.1.5 and JN.1 subvariants. Multivariate analysis assessed protective factors against a new SARS-CoV-2 infection between the two sampling times and 10 months follow up. Results:74% had hybrid immunity and 26% vaccine only immunity at study entry. A neutralizing antibody response was detected in 99% to Wuhan ancestral strain compared to 86% and 79% respectively to Omicron XBB.1.5 and JN.1 subvariants. For those with detectable antibodies the levels decayed, faster in those with vaccine only immunity and to the JN.1 subvariant. Neither the presence or the level of neutralizing antibody to JN.1 was associated with protection with a new SARS-Cov-2 infection over the 10-month follow up period. Conclusion:Neutralizing antibody levels to Omicron JN.1 subvariant were identified in 79% overall but in only 56% with vaccine only immunity. The presence or level was not associated with protection form a new SARS-CoV-2 infection over 10-months. This data supports the development of pan-coronavirus vaccine to expand protection against emerging variants.
Abstract Objective Several factors have been associated with altered risk of developing multiple sclerosis (MS). Epstein–Barr virus (EBV) is the critical risk factor for MS, but recent studies indicate that human herpesvirus 6A (HHV‐6A) and cytomegalovirus (CMV) are involved in MS aetiopathogenesis. We recently reported an association between rubella virus (RV) envelope protein 1 (E1) seropositivity and the risk of developing MS. Here, we aimed to further explore this association. Methods Bio‐banked blood samples collected before the onset of MS from 981 cases and 1278 matched controls were analysed for antibodies against RV envelope proteins 1 and 2 (E2), and serum‐neurofilament light chain (S‐NfL), a marker for axonal injury. The association between RV and MS was analysed with conditional logistic regression, calculating odds ratios (OR) with 95% confidence intervals (CI). Results Rubella E1 seropositivity was significantly associated with a higher risk of MS development, even when adjusting for EBV, CMV and HHV‐6A serostatus (OR = 1.67, 95% CI 1.29–2.14, P < 0.001). We also observed an increase in seroreactivity against RV E1 before an increase in S‐NfL in MS cases, indicating that increased RV E1 seroreactivity precedes axonal injury in the MS prodrome at group‐level. There was no association between RV E2 serostatus and MS risk. The association between RV E1 serostatus and MS risk remained similar when the analysis was restricted to unvaccinated participants (OR = 1.78, 95% CI 1.07–2.98, P = 0.028). Conclusions Our results support a broadening of the viral hypothesis in MS, arguing for further studies on the neurotropic RV in MS aetiology.
