Lymphocyte-associated Antigen Research Articles

Association of CTLA-4 gene polymorphisms with the genetic susceptibility and prognosis of patients with Bladder urothelial carcinoma

To assess the association of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) gene polymorphisms with the prognosis of patients with Bladder urothelial carcinoma (BUC). From February 2019 to October 2020, 256 BUS patients treated at the Xinxiang Central Hospital were selected as the study group, whilst 250 healthy individuals were selected as the control group. Genotypes of rs5742909 (-318C/T), rs231775 (+49A/G) and rs4553808 (-1661A/G) were determined by PCR-restriction fragment length polymorphism assay. The frequencies of genotypes and alleles of the CTLA-4 gene were compared between the two groups. All patients had undergone surgical treatment and were followed up for 3 years and divided into good prognosis group (n = 166) and poor prognosis group (n = 86) based on the status of disease. The distribution of alleles and genotypes were compared, and Kaplan-Meier analysis was used to assess the association of genetic polymorphisms with the prognosis. No significant difference was found in the gender, age, BMI, smoking history and alcohol use between the two groups (P > 0.05). The frequencies of GG genotype and G allele for the rs231775 (+49A/G) and rs4553808 (-1661A/G) loci were significantly higher in the study group compared with the control group (P < 0.05), whilst no statistical difference was found in the genotypic and allelic frequency for the rs5742909 locus between the two groups (P > 0.05). Among the 252 subjects who had completed follow-up, 86 had poor prognosis and 166 had good prognosis. The frequencies of GG genotype and G allele at the rs231775 (+49A/G) and rs4553808 (-1661A/G) loci were significantly lower in the good prognosis group compared with the poor prognosis group (P < 0.05). Kaplan-Meier survival curve analysis showed that the survival time of patients with GG genotype for the rs231775 (+49A/G) and rs4553808 (-1661A/G) loci was significantly shorter than patients with AA or AG genotypes (Log Rank 2 = 13.654, 9.974, P < 0.001). The polymorphisms of the rs231775 and rs4553808 loci of the CTLA-4 gene are associated with genetic susceptibility and poor prognosis for BUC, and a higher GG genotypic frequency may increase the risk for infection and poor prognosis of the patients.

Heterogeneous IL-9 Production by Circulating Skin-Tropic and Extracutaneous Memory T Cells in Atopic Dermatitis Patients

Interleukin (IL)-9 is present in atopic dermatitis (AD) lesions and is considered to be mainly produced by skin-homing T cells expressing the cutaneous lymphocyte-associated antigen (CLA). However, its induction by AD-associated triggers remains unexplored. Circulating skin-tropic CLA+ and extracutaneous/systemic CLA− memory T cells cocultured with autologous lesional epidermal cells from AD patients were activated with house dust mite (HDM) and staphylococcal enterotoxin B (SEB). Levels of AD-related mediators in response to both stimuli were measured in supernatants, and the cytokine response was associated with different clinical characteristics. Both HDM and SEB triggered heterogeneous IL-9 production by CLA+ and CLA− T cells in a clinically homogenous group of AD patients, which enabled patient stratification into IL-9 producers and non-producers, with the former group exhibiting heightened HDM-specific and total IgE levels. Upon allergen exposure, IL-9 production depended on the contribution of epidermal cells and class II-mediated presentation; it was the greatest cytokine produced and correlated with HDM-specific IgE levels, whereas SEB mildly induced its release. This study demonstrates that both skin-tropic and extracutaneous memory T cells produce IL-9 and suggests that the degree of allergen sensitization reflects the varied IL-9 responses in vitro, which may allow for patient stratification in a clinically homogenous population.

Expression patterns of immune checkpoint proteins and Plasmodium falciparum-induced cytokines in chronic hepatitis B virus-infected and uninfected individuals: A cross-sectional study.

Chronic hepatitis B virus (CHB) infection remains a major public health problem. The American Association for the Study of Liver Diseases (AASLD) 2018 Hepatitis B Guidelines provide that CHB individuals not requiring antiviral therapy yet are monitored to determine the need for antiviral therapy in the future; however, these tests do not include measurement of cytokines and immune cell characterization. This case-control study compared the cytokine and immune checkpoint protein expression profiles between CHB individuals not yet on antiviral treatment and hepatitis B virus (HBV)-negative individuals. CD4 and CD8 T cells from CHB and HBV-negative individuals were characterized for immune checkpoint proteins programmed cell death-1 (PD1), T cell Immunoglobulin domain and mucin domain-containing protein 3 (TIM-3), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) (CD152), and a memory marker CXCR3 (CD183) using flow cytometry. Malaria-induced cytokine expression levels were determined by stimulating their blood cells with Plasmodium falciparum 3D7 strain antigens (CSP, AMA-1, and TRAP) in whole blood assays, and cytokine levels were measured using a 13-plex Luminex kit. HBV-negative and CHB individuals had comparable levels of CD4+ and CD8+ T cells. However, a proportion of the CD4+ and CD8+ populations from both groups, which were CXCR3+, expressed PD-1 and CD152. The ability to produce cytokines in response to malaria antigen stimulation was not significantly different between the groups. These findings support excluding CHB individuals from antiviral therapy at this stage of infection. However, CHB individuals require regular monitoring to determine the need for later antiviral treatment.

Potential mechanisms and targeting strategies of the gut microbiota in antitumor immunity and immunotherapy.

Immunotherapies, notably immune checkpoints inhibitors that target programmed death 1/programmed death ligand 1(PD-1/PD-L1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), had profoundly changed the way advanced and metastatic cancers are treated and dramatically improved overall and progression-free survival. This review article aimed to explore the underlying molecular mechanisms by which the gut microbiota affects antitumor immunity and the efficacy of cancer immunotherapy. We summarized the latest knowledge supporting the associations among the gut microbiota, antitumor immunity, and immunotherapy. Moreover, we disscussed the therapeutic strategy for improving immunotherapy efficacy by modulating gut microbiota in cancer treatment. The potential molecular mechanisms underlying these associations are explained in terms of four aspects: immunomodulation, molecular mimicry, mamps, and microbial metabolites. The gut microbiota significantly impacts antitumor immunity and alters the effectiveness of cancer immunotherapy.

Glycosylation and Its Role in Immune Checkpoint Proteins: From Molecular Mechanisms to Clinical Implications.

Immune checkpoint proteins have become recent research hotspots for their vital role in maintaining peripheral immune tolerance and suppressing immune response function in a wide range of tumors. Therefore, investigating the immunomodulatory functions of immune checkpoints and their therapeutic potential for clinical use is of paramount importance. The immune checkpoint blockade (ICB) is an important component of cancer immunotherapy, as it targets inhibitory immune signaling transduction with antagonistic antibodies to restore the host immune response. Anti-programmed cell death-1 (PD-1) and anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) monoclonal antibodies are two main types of widely used ICBs that drastically improve the survival and prognosis of many patients with cancer. Nevertheless, the response rate of most cancer types remains relatively low due to the drug resistance of ICBs, which calls for an in-depth exploration to improve their efficacy. Accumulating evidence suggests that immune checkpoint proteins are glycosylated in forms of N-glycosylation, core fucosylation, or sialylation, which affect multiple biological functions of proteins such as protein biosynthesis, stability, and interaction. In this review, we give a brief introduction to several immune checkpoints and summarize primary molecular mechanisms that modulate protein stability and immunosuppressive function. In addition, newly developed methods targeting glycosylation on immune checkpoints for detection used to stratify patients, as well as small-molecule agents disrupting receptor-ligand interactions to circumvent drug resistance of traditional ICBs, in order to increase the clinical efficacy of immunotherapy strategies of patients with cancer, are also included to provide new insights into scientific research and clinical treatments.

Efficacy and safety of personalized optimal PD-(L)1 combinations in advanced NSCLC: a network Meta-Analysis.

Programmed death 1 (PD-1)/programmed death 1 ligand 1 (PD-L1)-directed immunotherapy has revolutionized the treatments for advanced non-small cell lung cancer (NSCLC), whereas the optimal therapeutic combinations remain uncertain. Our study encompassed phase Ⅱ/III randomized controlled trials (RCTs) that involved anti-PD-(L)1-based therapies for stage-IV NSCLC. The primary outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and incidences of adverse events (AEs). Subgroup analyses were conducted by treatment lines, PD-L1 expression levels, histological types, and metastatic sites. Our analysis incorporated 38 publications, covering 14 therapeutic combinations and involving 18,048 participants. PD-(L)1+chemotherapy (CT), PD-(L)1+ cytotoxic T lymphocyte-associated antigen-4 (CTLA4) +CT, and PD-(L)1+ T-cell immunoglobulin and ITIM domain (TIGIT) were notably effective in prolonging OS. Overall, PD-(L)1+CT and PD-(L)1+CT+ vascular endothelial growth factor (VEGF) were significantly beneficial for PFS and ORR. As for the subsequent-line treatments, incorporating radiotherapy can enhance PFS and ORR (ranked fourth among enrolled treatments). For patients with PD-L1 < 1%, PD-(L)1+CT+VEGF and PD-(L)1+CTLA4+CT were favorable approaches. Conversely, in patients with PD-L1 ≥ 50%, PD-(L)1+CT represented an effective treatment. Patients with non-squamous cell carcinoma or liver metastases might benefit from the addition of VEGF. In cases of squamous cell carcinoma or brain metastases, the combination of PD-(L)1+CTLA4+CT yielded superior benefits. This study underscores the enhanced efficacy of combination immunotherapies over monotherapy. It highlights the necessity for personalized treatment, considering individual factors. These insights are vital for clinical decision-making in the management of advanced NSCLC.

Genetic and Epigenetic Etiologies of Type 1 Diabetes Mellitus

Numerous suspect genes associated with type 1 diabetes mellitus (T1DM) have been identified, suggesting a need to focus on the disease's causal genes and mechanisms. This necessitates an update to raise public awareness. This review articulates genes with mutations that predispose individuals to T1DM. We conducted a comprehensive search of academic databases, including Web of Science, Scopus, PubMed, and Google Scholar, for relevant materials. Available information indicates that at least 70 genes are suspected in the pathogenesis of T1DM. However, the most frequently implicated genes include human leukocyte antigen (HLA), insulin (INS), cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), and protein tyrosine phosphatase non-receptor type 22 (PTPN22). Mutations or variants in these genes may lead to insulin insufficiency and, consequently, T1DM by tricking immune cells, such as T-cells and B-cells, into attacking self-antigens and triggering the autoimmunity of beta cells. Furthermore, this pathophysiology can be mediated through aberrant epigenetic modifications, including DNA methylation, histone post-translational modifications, and noncoding RNAs, in the mentioned genes. Some of these pathophysiologies are gene-specific and may have an epigenetic origin that is reversible. In the event of an epigenetic origin, a treatment for T1DM that addresses the causal genes or reverses epigenetic changes and their mechanisms could yield improved outcomes. Medical professionals are encouraged to design therapeutic regimens that specifically target the mentioned genes and address the identified epigenetic alterations in individuals expressing such etiologies.

The evolving role of immune checkpoint inhibitors in cervical and endometrial cancer.

The introduction of immune checkpoint inhibitors (ICIs) has revolutionized the treatment landscape for numerous tumor types, including cervical and endometrial cancers. Multiple ICIs against programmed cell death-1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) have demonstrated encouraging outcomes in controlled clinical studies for advanced cervical and endometrial cancers. For advanced cervical cancer, approved ICIs as second-line treatment include cemiplimab, nivolumab, and pembrolizumab as single agents. In the first-line treatment setting, options include pembrolizumab alone or in combination with bevacizumab, as well as atezolizumab combined with a backbone platinum-based chemotherapy plus bevacizumab. Additionally, for locally advanced cervical cancer, pembrolizumab is recommended alongside concurrent chemoradiotherapy. For endometrial cancer, pembrolizumab monotherapy, pembrolizumab in combination with lenvatinib, and dostarlimab are currently approved as second-line treatment options. Moreover, either dostarlimab or pembrolizumab can be added to first-line platinum-based chemotherapy for mismatch repair deficient malignancies. Although the inclusion of these agents in clinical practice has led to improved overall response rates and survival outcomes, many patients still lack benefits, possibly due to multiple intrinsic and adaptive resistance mechanisms to immunotherapy. This review aims to highlight the rationale for utilizing ICIs and their current role, while also delineating the proposed mechanisms of resistance to ICIs in cervical and endometrial cancer.

The efficacy and safety of a novel PD-1/CTLA-4 bispecific antibody cadonilimab (AK104) in advanced non-small cell lung cancer: A multicenter retrospective observational study in China.

e20518 Background: Treatment choice for advanced non-small cell lung cancer (NSCLC) after front-line immuno-chemotherapy therapy is limited. As the first approved dual programmed cell death-1(PD-1) / cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) bispecific antibody worldwide, cadonilimab combined with anlotinib, a vascular epidermal growth factor tyrosine kinase inhibitor, showed potential anti-tumor activity in advanced NSCLC patients resistant to anti-PD-1/ programmed cell death ligand-1(PD-L1) antibodies in a phase Ib/II clinical trial. Methods: We retrospectively collectedthe efficacy and safety data in advanced NSCLC patients treated with cadonilimab in later therapy lines. The primary endpoints were objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and safety results. The secondary endpoints were overall survival (OS). Results: Totally, 41 advanced NSCLC patients who were refractory to previous chemotherapy and anti-PD-1/PD-L1 therapy and treated with later line cadonilimab-based regimens were enrolled. More than half of patients received cadonilimab as a fourth or later line of treatment. Until the data cut-off date (August 29, 2023), the treatment efficacy of 23 patients could be evaluated. One (4.3%) patient had partial response, 8 (34.8%) patients had stable disease, and 14 (60.9%) patients progressed. The ORR and DCR were 4.3% and 39.1%, respectively. The median PFS of all evaluated patients was 108.0 days (95% confidence interval: 62.3-153.7). Due to the short follow-up, median OS has not been reached yet. Treatment-related adverse events (TRAEs) and immune-related adverse events (irAEs) occurred in 26(63.4%) and 9(22%) patients, respectively. The most common AEs included gamma-glutamyl transferase elevation (17.1%), coughing (14.6%), and fatigue (12.2%). Five patients (12.2%) experienced grade≥3 AEs. Two patients temporarily paused medication due to Grade 2 rash. One patient and 2 patients permanently discontinued medication due to Grade 3 myocarditis and Grade 2 infusion reactions, respectively. Metabolomics results showed that lipids and lipid-like molecules were rich in stools of patients responsive to cadonilimab treatment. Conclusions: In this heavily treated advanced NSCLC patient cohort, cadonilimab-based regimens only showed moderate anti-tumor efficacy with a generally tolerable and manageable safety profile. More evidence supporting administration of cadonilimab is needed in NSCLC patients refractory to previous anti-PD-1/PD-L1 therapy.

Inhibition of interferon regulatory factor 4 orchestrates T cell dysfunction, extending mouse cardiac allograft survival.

T cell dysfunction, which includes exhaustion, anergy, and senescence, is a distinct T cell differentiation state that occurs after antigen exposure. Although T cell dysfunction has been a cornerstone of cancer immunotherapy, its potential in transplant research, while not yet as extensively explored, is attracting growing interest. Interferon regulatory factor 4 (IRF4) has been shown to play a pivotal role in inducing T cell dysfunction. A novel ultra-low-dose combination of Trametinib and Rapamycin, targeting IRF4 inhibition, was employed to investigate T cell proliferation, apoptosis, cytokine secretion, expression of T-cell dysfunction-associated molecules, effects of MAPK and mammalian target of Rapamycin (mTOR) signaling pathways, and allograft survival in both in vitro and BALB/c to C57BL/6 mouse cardiac transplantation models. In vitro, blockade of IRF4 in T cells effectively inhibited T cell proliferation, increased apoptosis, and significantly upregulated the expression of programmed cell death protein 1 (PD-1), Helios, CD160, and cytotoxic T lymphocyte-associated antigen (CTLA-4), markers of T cell dysfunction. Furthermore, it suppressed the secretion of pro-inflammatory cytokines interferon (IFN)-γ and interleukin (IL)-17. Combining ultra-low-dose Trametinib (0.1mg·kg-1·day-1) and Rapamycin (0.1mg·kg-1·day-1) demonstrably extended graft survival, with 4 out of 5 mice exceeding 100 days post-transplantation. Moreover, analysis of grafts at day 7 confirmed sustained IFN regulatory factor 4 (IRF4) inhibition, enhanced PD-1 expression, and suppressed IFN-γ secretion, reinforcing the in vivo efficacy of this IRF4-targeting approach. The combination of Trametinib and Rapamycin synergistically inhibited the MAPK and mTOR signaling network, leading to a more pronounced suppression of IRF4 expression. Targeting IRF4, a key regulator of T cell dysfunction, presents a promising avenue for inducing transplant immune tolerance. In this study, we demonstrate that a novel ultra-low-dose combination of Trametinib and Rapamycin synergistically suppresses the MAPK and mTOR signaling network, leading to profound IRF4 inhibition, promoting allograft acceptance, and offering a potential new therapeutic strategy for improved transplant outcomes. However, further research is necessary to elucidate the underlying pharmacological mechanisms and facilitate translation to clinical practice.

Current research insights into the role of CTLA-4 in hepatitis B virus (HBV) infection.

Chronic hepatitis B virus (HBV) infection is a significant global public health concern, and the clearance of HBV is closely linked to the activity of HBV-specific T cells, which is regulated by various co-suppressor molecules. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is among these co-suppressor molecules which induces T cell exhaustion by competitively inhibiting CD28 and dampening the function of HBV-specific T cells. CTLA-4 also plays a role in the regulation of T helper (Th) cell differentiation and influences cytokine release. In addition, CTLA-4 can impact glucose metabolism in hepatocellular carcinoma through its interaction with T regulatory (Treg) cells. This review aims to provide a comprehensive overview of the existing literature related to the role of CTLA-4 in HBV patients across different subsets of T cells. Additionally, we propose a discussion on the possible mechanisms through which CTLA-4 may contribute to HBV infection, as well as the development of HBV-induced cirrhosis and hepatocellular carcinoma.

Single-cell RNA sequencing reveals the expansion of circulating tissue-homing B cell subsets in secondary acute dengue viral infection

The roles of antibodies secreted by subsets of B cells in dengue virus (DENV) infection have been extensively studied, yet, the contribution of tissue-homing B cells to antiviral immunity remains unclear. In this study, we performed a comprehensive analysis of B cell subpopulations in peripheral blood samples from DENV-infected patients using single-cell RNA-sequencing (scRNA-seq) datasets and flow cytometry. We showed that plasma cells (PCs) and plasmablasts (PBs) were the predominant B cell populations during the acute phase of secondary natural DENV infection, but not in convalescent phase nor in healthy controls. Interestingly, these cells expressed proliferation, adhesion, and tissue-homing genes, including SELPLG, a homing marker of the skin, the initial infected site of DENV. Flow cytometry analysis confirmed a significant upregulation of cell surface expression of a cutaneous lymphocyte-associated antigen (CLA) encoded by SELPLG in PCs and PBs, compared to naive and memory B cells from the same patients. The analysis of an independent single-cell B-cell receptor sequencing (scBCR-seq) dataset of DENV-infected patients revealed that the peripheral blood PCs and PBs exhibited the highest clonal expansion in secondary DENV infection compared to other B cell subsets. These clonally expanded cells also expressed the highest levels of tissue-homing genes, including SELPLG. In addition, by utilizing a public scRNA-seq dataset of SARS-CoV2 infection, we demonstrated the upregulation of several tissue-homing genes in PCs and PBs. Our study provides evidence for the potential roles of tissue-homing B cell subsets in the context of immune responses against viral infections in humans.

Leukocyte dysfunction and reduced CTLA-4 expression are associated with perianal Crohn's disease.

Although perianal Crohn's disease (PCD) is highly associated with the exacerbated inflammation, the molecular basis and immunological signature that distinguish patients who present a history of perianal lesions are still unclear. This paper aims to define immunological characteristics related to PCD. In this cross-sectional observational study, we enrolled 20 healthy controls and 39 CD patients. Blood samples were obtained for the detection of plasma cytokines and lipopolysaccharides (LPS). Peripheral blood mononuclear cells (PBMCs) were phenotyped by flow cytometry. Leukocytes were stimulated with LPS or anti-CD3/anti-CD28 antibodies. Our results show that CD patients had augmented plasma interleukin (IL)-6 and LPS. However, their PBMC was characterized by decreased IL-6 production, while patients with a history of PCD produced higher IL-6, IL-8, and interferon-γ, along with decreased tumor necrosis factor alpha (TNF). CD patients had augmented FoxP3 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) regulatory markers, though the PCD subjects presented a significant reduction in CTLA-4 expression. CTLA-4 as well as IL-6 and TNF responses were able to distinguish the PCD patients from those who did not present perianal complications. In conclusion, IL-6, TNF, and CTLA-4 exhibit a distinct expression pattern in CD patients with a history of PCD, regardless of disease activity. These findings clarify some mechanisms involved in the development of the perianal manifestations and may have a great impact on the disease management.

Fine-tuning tumor- and allo-immunity: advances in the use of immune checkpoint inhibitors in kidney transplant recipients.

Cancer is a common complication after kidney transplantation. Kidney transplant recipients (KTR) have a 2- to 4-fold higher risk of developing cancer compared to the general population and post-transplant malignancy is the third most common cause of death in KTR. Moreover, it is well known that certain cancer types are overrepresented after transplantation, especially non-melanoma skin cancer. Immune checkpoint inhibitors (ICI) have revolutionized the treatment of cancer, with remarkable survival benefit in a subgroup of patients. ICI are monoclonal antibodies that block the binding of specific co-inhibitory signaling molecules. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), programmed cell death protein 1 (PD-1), and its ligand programmed cell death ligand 1 (PD-L1) are the main targets of ICI. Solid organ transplant recipients (SOTR) have been excluded from clinical trials owing to concerns about tumor response, allo-immunity, and risk of transplant rejection. Indeed, graft rejection has been estimated as high as 48% and represents an emerging problem. The underlying mechanisms of organ rejection in the context of treatment with ICI are poorly understood. The search for restricted antitumoral responses without graft rejection is of paramount importance. This review summarizes the current knowledge of the use of ICI in KTR, the potential mechanisms involved in kidney graft rejection during ICI treatment, potential biomarkers of rejection, and how to deal with rejection in clinical practice.

Immunotherapy of Human Melanoma: Past, Present, Future.

Immunotherapy with immune checkpoint inhibitors (ICIs) is a promising therapeutic schedule in advanced solid cancers. In this review, clinical trials from highly reputable journals are interpreted for safety and efficacy evaluation of the common anti-programmed death-1 (PD-1) inhibitor nivolumab and/or the most known anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) inhibitor ipilimumab in advanced melanoma. Current progress in the field of melanoma immunotherapy is the focus of this review. Solo nivolumab and combo nivolumab-ipilimumab show higher responses compared to solo ipilimumab or chemotherapy. BRAF and programmed death-ligand 1 (PDL1) expression states are seemingly not reliable biomarkers of response to ICI therapy in melanoma. Solo ipilimumab and particularly a combination of nivolumab-ipilimumab show higher adverse events (AEs) compared with solo nivolumab or chemotherapy. Besides, ICI therapy is safer in mucosal melanoma, but its efficacy is higher in the cutaneous subtype. Patients receiving combination regimens who are experiencing serious AEs can discontinue such regimens until recovery and still maintain clinical benefits. To conclude, combo nivolumab-ipilimumab represents more therapeutic advantages compared with solo nivolumab or ipilimumab, but the rate of AEs is higher for combination regimens. Resistance to combo nivolumab-ipilimumab demands the application of novel approaches to go with ICIs in melanoma immunotherapy. Immunogenic agents, alternative immune checkpoints, vaccination, oncolytic viruses, extracellular vesicles (EVs) and fecal microbiome transplantation (FMT) are novel strategies in patients developing ICI resistance.

Low dose post-transplant cyclophosphamide and sirolimus induce mixed chimerism with CTLA4-Ig or lymphocyte depletion in an MHC-mismatched murine allotransplantation model

Allogeneic hematopoietic cell transplantation (allo-HCT) offers a curative option for patients with certain non-malignant hematological diseases. High-dose post-transplant cyclophosphamide (PT-Cy) (200 mg/kg) and sirolimus (3 mg/kg), (HiC) synergistically induce stable mixed chimerism. Further, sirolimus and cytotoxic T lymphocyte-associated antigen-4 immunoglobulin (CTLA4-Ig), also known as Abatacept (Aba), promote immune tolerance and allograft survival. Here, in a major histocompatibility complex (MHC)-mismatched allo-HCT murine model, we combined Aba and/or T-cell depleting anti-Thy1.2 (Thy) with a lower dose of PT-Cy (50 mg/kg) and Sirolimus (3 mg/kg), (LoC). While mice in the LoC group showed graft rejection, the addition of Thy to LoC induced similar donor chimerism levels when compared to the HiC group. However, the addition of Aba to LoC led to graft acceptance only in younger mice. When Thy was added to the LoC+Aba setting, graft acceptance was restored in both age groups. Engrafted groups displayed significantly reduced frequencies of recipient-specific interferon-γ-producing T cells as well as an increased frequency in regulatory T cells (Tregs) except in the LoC+Aba group. Splenocytes from engrafted mice showed no proliferation upon restimulation with Balb/c stimulators. Collectively, in combination with Aba or Thy, LoC may be considered to reduce graft rejection in patients who undergo allo-HCT.

Increased cAMP-PKA signaling pathway activation is involved in up-regulation of CTLA-4 expression in CD4+ T cells in acute SIVmac239-infected Chinese rhesus macaques

Human immunodeficiency virus-1 (HIV-1) infection can cause chronic activation, exhaustion, and anergy of the immune system. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is an immune checkpoint molecule, which plays an important role in immune homeostasis and disease. CTLA-4 expression is elevated in HIV-1-infected patients and is associated with disease progression. However, the mechanism controlling expression of CTLA-4 in HIV-1 infection is poorly characterized. In this study, we used a SIV-infected Chinese rhesus macaque (ChRM) model to explore CTLA-4 expression in SIV infection. Results showed that SIV infection significantly increased CTLA-4 expression in all T cell subsets, especially central memory T cells. CTLA-4+CD4+ T cell frequency was significantly associated with disease progression markers. Activation of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling pathway regulated CTLA-4 expression in CD4+T cells, as confirmed by stimulation with dibutyryl cyclic adenosine monophosphate, forskolin, and 3-isobutyl-1-methylxanthine, and inhibition with H-89 ex vivo. Simultaneously, cAMP concentration in PBMCs and PKA activity in both PBMCs and CD4+ T cells were increased in acute SIV-infected ChRMs, accompanied by an increase in adenylate cyclase 6 expression and a decrease in cAMP-phosphodiesterase 3A (PDE3A), PDE4B, and PDE5A expression in PBMCs. In addition, selective inhibition of PDE4B and PDE5A activity enhanced CTLA-4 expression in CD4+ T cells. These results suggest that SIV infection alters cAMP metabolism and increases cAMP-PKA signaling pathway activation, which up-regulates the expression of CTLA-4 in acute SIVmac239-infected ChRMs. Thus, regulation of the cAMP-PKA signaling pathway may be a potential strategy for the restoration of T cell function and therapy for AIDS.

ADJUBIL: A phase II study of immunotherapy with durvalumab and tremelimumab in combination with capecitabine or without capecitabine in adjuvant situation for biliary tract cancer.

TPS583 Background: Despite improvements in multidisciplinary healthcare, patients with biliary tract cancer (BTC) have a poor outcome and effective treatment options are limited. Only 20 % of patients are eligible for surgical resection with curative intent, with 5-year overall survival rates &lt; 10 % for all patients. Data on adjuvant chemotherapy alone for BTC are conflicting, and the SOC is treatment with capecitabine according to the UK BILCAP trial, even though BILCAP was formally negative. Based on the positive data for durvalumab in the TOPAZ-1 trial in BTC and for the STRIDE regimen in HCC according to the Himalaya trial data, the evaluation of the IO combination in the adjuvant setting seems promising. Also, the MediTreme trial showed promising response rates in BTC. Preclinical studies indicate that the antibody combination leads to stronger and more durable anti-tumour effects than single therapies, as it synergistically modulates the tumour's immunosuppressive microenvironment, which is particularly pronounced in cholangiocarcinoma. The aim of the ADJUBIL trial is to evaluate the clinical activity of the anti-PD-L1 (programmed-death 1 ligand) antibody durvalumab and the anti-CTLA-4 (cytotoxic T- lymphocyte-associated antigen 4) antibody tremelimumab in combination with or without capecitabine in patients with respectable BTC in the adjuvant setting. This is a randomized phase II study with a pick-the-winner design. The winner of ADJUBIL could be tested against the current SOC capecitabine in a subsequent phase 2/3 trial. Methods: The ADJUBIL trial is an open-label, multicenter phase II study, including patients with BTC after curative surgery (R0/R1) with no previous systemic treatment. Patients are randomized (1:1) to receive either tremelimumab (300 mg, one dose on C1D1) plus durvalumab (1500 mg every 4 weeks; max. 12 months), with or without capecitabine (1250 mg/m2 twice a day on day 1-14 of 3-weekly cycles; max. 8 cycles). 40 evaluable patients will be enrolled in the study to receive anticancer treatment until disease recurrence or intolerable toxicities. Primary objective is to assess the anti-tumor activity of the treatment in both arms by the recurrence-free survival rate after 12 months. Secondary endpoints are recurrence-free survival, overall survival, toxicity, and quality of life. Exploratory endpoints are to identify predictive biomarkers for recurrence-free survival and overall survival. Study start of the ADJUBIL trial was in June 2021. By September 2023, 15 centers in Germany have been activated and 23 out of 40 planned patients have been enrolled. The first 5 patients in each arm were subject to a safety lead-in phase with close monitoring of (serious) adverse events. The safety assessment revealed no concerns. The study is ongoing. Clinical trial information: NCT05239169 .

Functional analysis of virus-specific CD4(+)T cells and CD8(+)T cells in patients with liver injury caused by Epstein-Barr virus infection

Objective: To analyze the functional differences between virus-specific CD4(+)T cells and CD8(+)T cells in patients infected with Epstein-Barr virus (EBV) who develop liver injury and those who do not. Methods: 45 cases of EBV infections were enrolled, including 28 cases developing liver injuries and 17 that did not. Mononuclear cells from peripheral blood were isolated. CD4(+)T cells and CD8(+)T cells were purified and cultured using recombinant EBV core antigen 2 (EBNA2) for 96 h with stimulation. The CCK-8 method was used to detect cell proliferation. Flow cytometry was used to detect the proportion of CD4(+)T cells and CD8(+)T cells. An enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of CD4(+)T cells secreting cytokines and CD8(+)T cells secreting molecular toxicity. Real-time quantitative PCR was used to detect the mRNA levels of transcription factors and molecular toxicity in CD4(+)T cell subsets. Flow cytometry was used to detect the immune checkpoints at molecular levels in CD8(+)T cells. The inter-group comparison was performed using a t-test or Mann-Whitney test. Results: There was no statistically significant difference (P > 0.05) in the proliferation proportion of peripheral blood mononuclear cells, CD4(+)T cells, and CD8(+)T cells after stimulation with recombinant EBNA2 between the EBV-infected non-liver injury group and the infected liver injury group (P > 0.05). There was no statistically significant difference in the proportion of CD4(+)T cells secreting related cytokines and the mRNA levels of transcription factors after stimulation with recombinant EBNA2 between the EBV-infected non-liver injury group and the infected liver injury group (P > 0.05).The levels of perforin secreted by CD8(+)T cells and granzyme B after stimulation with recombinant EBNA2 were higher in the EBV infection-induced liver injury group than those in the non-liver injury group [(75.51±23.33) pg/ml vs. (58.99±18.39) pg/ml, P = 0.017] [(117.8±44.55) pg/ml vs. (90.22±34.21) pg/ml, P = 0.034]. The mRNA levels of Fas ligand and tumor necrosis factor-related apoptosis-inducing ligand in CD8(+)T cells in the liver injury group caused by EBV infection were approximately 1.5 and 1.2 times higher than those in the non-liver injury group, respectively, and the difference was statistically significant (P < 0.001), but there was no statistically significant difference in the proportional expression of programmed cell death-1 and cytotoxic T lymphocyte-associated antigen-4 in CD8(+)T cells between the EBV-infected non-liver injury group and infected liver injury group (P > 0.05) Conclusion: Patients with liver injury caused by EBV infection have strong virus-specific CD8(+) T cell toxic effects, which may mediate EBV-induced liver injury.

Tremelimumab: A Review in Advanced or Unresectable Hepatocellular Carcinoma.

Tremelimumab (tremelimumab-actl; Imjudo®) is a monoclonal antibody and immune checkpoint inhibitor (ICI) that blocks cytotoxic T lymphocyte-associated antigen-4 (CTLA-4). A single, priming dose of intravenous tremelimumab is used in combination with durvalumab, an ICI that blocks programmed cell-death ligand 1, in a regimen known as STRIDE (Single Tremelimumab Regular Interval Durvalumab). STRIDE is approved for the treatment of adults with unresectable hepatocellular carcinoma (HCC) in the USA and Japan and for the first-line treatment of adults with advanced or unresectable HCC in Europe. In the phase III HIMALAYA trial, STRIDE significantly improved overall survival (OS) compared with sorafenib in adults with unresectable HCC and no prior systemic therapy. A higher proportion of STRIDE versus sorafenib recipients had an objective response to treatment. The OS benefit associated with STRIDE was sustained with 4 years' follow-up. STRIDE had a manageable safety profile that differed from that of sorafenib. Grade 3 or 4 treatment-related adverse events occurred in a lower proportion of STRIDE versus sorafenib recipients. Based on the available evidence, tremelimumab used as part of the STRIDE regimen is a valuable first-line agent that expands the treatment options available to patients with advanced or unresectable HCC.