A review of cancer immunotherapy toxicity.

Cancer immunotherapies, including checkpoint inhibitors and adoptive cell therapy, manipulate the immune system to recognize and attack cancer cells. These therapies have the potential to induce durable responses in multiple solid and hematologic malignancies and thus have transformed treatment algorithms for numerous tumor types. Cancer immunotherapies lead to unique toxicity profiles distinct from the toxicities of other cancer therapies, depending on their mechanism of action. These toxicities often require specific management, which can include steroids and immune-modulating therapy and for which consensus guidelines have been published. This review will focus on the toxicities of checkpoint inhibitors and chimeric antigen receptor T cells, including pathophysiology, diagnosis, and management.

Nivolumab in unresectable advanced, recurrent or metastatic esophageal squamous cell carcinoma.

Esophageal cancer (EC) is the eighth most common cancer worldwide. In view of biology and anatomical restrictions, multimodality treatment strategies have been developed for EC. However, the prognosis of patients with advanced EC remains especially poor. Immunotherapy, such as PD-1/PD-L1 and CTLA-4/B7 blockade, has emerged as a potent treatment for many types of cancer and has been approved in many countries. Based on the results of the ATTRACTION-3 trial, nivolumab, an anti-PD-1 monoclonal antibody, was approved by the US FDA for patients with platinum-resistant, unresectable, recurrent or metastatic esophageal squamous cell carcinoma. The CheckMate 648 trial demonstrated that the combination of nivolumab with platinum-based fluoropyrimidine chemotherapy and combination immunotherapy with nivolumab and ipilimumab, an anti-CTLA-4 monoclonal antibody, showed a survival benefit in patients with advanced esophageal squamous cell carcinoma compared with doublet chemotherapy. This review focuses on nivolumab-containing treatments for patients with advanced esophageal squamous cell carcinoma.

Soluble cytotoxic T-lymphocyte antigen-4 (sCTLA-4) in children with immune cytopenia: relation to disease activity.

Cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) is a costimulatory receptor exhibiting a potent inhibitory signal on antigen-activated immune responses. A soluble form, sCTLA-4, has been identified and was found to be increased in several autoimmune diseases. We aimed to evaluate serum levels of sCTLA-4 in different immune cytopenias, and to determine its possible relation to the disease activity. We measured serum levels of sCTLA-4 in 47 patients with immune cytopenias and compared them to 47 age- and sex-matched healthy controls. sCTLA-4 levels were significantly higher in patients with immune cytopenias compared to healthy controls (p < 0.001), however, levels were comparable between different groups of immune cytopenias (p = 0.084). Serum sCTLA-4 inversely correlated with age at diagnosis and hemoglobin level (p = 0.048, and p = 0.039 respectively), while it directly correlated with disease duration (p = 0.023) as well as markers of hemolysis including reticulocyte count, serum LDH and indirect bilirubin (p = 0.025; p = 0.019; p = 0.004 respectively). In the AIHA group, serum sCTLA-4 levels were significantly lower in patients in remission compared to patients with active disease (p = 0.026). Children with immune cytopenia exhibit significantly higher levels of circulating sCTLA-4 which correlated with disease activity, yet the prognostic significance and its use to tailor treatment regimen require additional studies.

The Microbiome in Advanced Melanoma: Where Are We Now?

PURPOSE OF REVIEW: This review summarizes recent data linking gut microbiota composition to ICI outcomes and gut microbiota-specific interventional clinical trials in melanoma. RECENT FINDINGS: Preclinical and clinical studies have demonstrated the effects of the gut microbiome modulation upon ICI response in advanced melanoma, with growing evidence supporting the ability of the gut microbiome to restore or improve ICI response in advanced melanoma through dietary fiber, probiotics, and FMT. Immune checkpoint inhibitors (ICI) targeting the PD-1, CTLA-4, and LAG-3 negative regulatory checkpoints have transformed the management of melanoma. ICIs are FDA-approved in advanced metastatic disease, stage III resected melanoma, and high-risk stage II melanoma and are being investigated more recently in the management of high-risk resectable melanoma in the peri-operative setting. The gut microbiome has emerged as an important tumor-extrinsic modulator of both response and immune-related adverse event (irAE) development in ICI-treated cancer in general, and melanoma in particular.

Impact of sex on prognosis in patients with advanced renal cell carcinoma treated with immune checkpoint inhibitors.

BACKGROUND: Prognostic impact of sex in patients with malignancies treated with immune checkpoint inhibitors has been intensively discussed but remains unclear, especially in advanced renal cell carcinoma. METHODS: We retrospectively evaluated a total of 184 patients with advanced renal cell carcinoma treated with either nivolumab plus ipilimumab combined treatment as first-line therapy (n = 73) or nivolumab as later-line therapy (n = 111) at our affiliated institutions. Progression-free survival, overall survival and objective response rate as well as adverse event profile were compared between sexes. RESULTS: Of the total 184 patients, 48 (26%) were female. Female patients had a significantly shorter progression-free survival than male patients (median: 3.8 vs. 8.3 months, P = 0.0005), but overall survival (median: 39.2 vs. 45.1 months, P = 0.283) and objective response rate (29% vs. 42%, P = 0.119) were not different between them. Similar findings were observed when analyzing within each treatment; in both patient groups treated with nivolumab plus ipilimumab combined therapy and nivolumab monotherapy, progression-free survival was significantly shorter in female than in male patients (P = 0.007, P = 0.017), but overall survival (P = 0.914, P = 0.117) and objective response rate (P = 0.109, P = 0.465) were comparable between them. Moreover, in a more restricted cohort consisting of patients with clear-cell renal cell carcinoma, a shorter progression-free survival in female patients was also observed (3.8 vs. 11.0 months, P < 0.0001). CONCLUSIONS: This retrospective study showed that immune checkpoint inhibitors-based treatment for renal cell carcinoma exhibited less marked effects in female than in male patients. Thus, sex may be an important factor for decision-making on systemic therapy as renal cell carcinoma treatment, although further studies are required to validate the present findings.

Sarcomatoid urothelial carcinoma of the renal pelvis treated with immunotherapy.

BACKGROUND: Sarcomatoid carcinoma is a rare, high-grade malignancy with epithelial and mesenchymal components. It may be a good candidate for immunotherapy because it is associated with overexpression of programmed cell death ligand 1. Sarcomatoid urothelial carcinoma (UC) of the upper urinary tract is extremely rare. Here we report the first case of sarcomatoid UC of the renal pelvis that responded to immunotherapy. CASE PRESENTATION: A 79-year-old man was referred to our hospital complaining of various symptoms, including anorexia and abdominal pain. A computed tomography scan revealed a right atrial tumor, a 9 cm left renal mass with a renal vein tumor thrombus, para-aortic lymphadenopathy, and multiple small lung nodules. The patient underwent resection of the right atrial tumor. Pathological analysis of the tumor did not lead to an accurate diagnosis even after several rounds of immunohistochemistry. He underwent a needle biopsy of the left kidney and was initially diagnosed with collecting duct carcinoma, a rare subtype of renal cell carcinoma (RCC). Following the initial diagnosis, immunotherapy with nivolumab and ipilimumab commenced. Thereafter, almost all lesions, including the left renal tumor, were reduced in size. However, he underwent a left nephrectomy approximately a year after beginning immunotherapy due to repeated left renal bleeding. Histological examination of the nephrectomy specimen revealed two forms of cancer-sarcomatoid UC and conventional high-grade UC. Two months after surgery, the patient was found to have new lung metastases. He underwent chemotherapy with gemcitabine and cisplatin, followed by immunotherapy with pembrolizumab. However, both treatments were ineffective. The patient died of cancer 19 months after his first admission. CONCLUSIONS: The presented case of sarcomatoid UC of the renal pelvis that partially responded to immunotherapy suggests that immunotherapy can be a promising treatment for sarcomatoid UC.

A Concerted Vision to Advance the Knowledge of Diabetes Mellitus Related to Immune Checkpoint Inhibitors.

The rubric of immune-related (ir) diabetes mellitus (DM) (irDM) encompasses various hyperglycemic disorders related to immune checkpoint inhibitors (ICPis). Beyond sharing similarities with conventional DM, irDM is a distinct, yet important, entity. The present narrative review provides a comprehensive overview of the literature regarding irDM published in major databases from January 2018 until January 2023. Initially considered rare, irDM is increasingly being reported. To advance the knowledge of irDM, the present review suggests a concerted vision comprising two intertwined aspects: a scientific-centered and a patient-centered view. The scientific-centered aspect addresses the pathophysiology of irDM, integrating: (i) ICPi-induced pancreatic islet autoimmunity in genetically predisposed patients; (ii) altered gut microbiome; (iii) involvement of exocrine pancreas; (iv) immune-related acquired generalized lipodystrophy. The patient-centered aspect is both nurtured by and nurturing the four pillars of the scientific-centered aspect: awareness, diagnosis, treatment, and monitoring of irDM. The path forward is a multidisciplinary initiative towards: (i) improved characterization of the epidemiological, clinical, and immunological profile of irDM; (ii) standardization of reporting, management, and surveillance protocols for irDM leveraging global registries; (iii) patient stratification according to personalized risk for irDM; (iv) new treatments for irDM; and (v) uncoupling ICPi efficacy from immunotoxicity.

What did we learn from CTLA-4 insufficiency on the human immune system?

Cytotoxic-T-lymphocyte-antigen-4 (CTLA-4) is a negative immune regulator constitutively expressed on regulatory T (Treg) cells and upregulated on activated T cells. CTLA-4 inhibits T cell activation by various suppressive functions including competition with CD28, regulation of the inhibitory function of Treg cells, such as transendocytosis, and the control of adhesion and motility. Intrinsic CTLA-4 signaling has been controversially discussed, but so far no distinct signaling pathway has been identified. The CTLA-4-mediated Treg suppression plays an important role in the maintenance of peripheral tolerance and the prevention of autoimmune diseases. Human CTLA-4 insufficiency is caused by heterozygous germline mutations in CTLA4 and characterized by a complex immune dysregulation syndrome. Clinical studies on CTLA4 mutation carriers showed a reduced penetrance and variable expressivity, suggesting modifying factor(s). One hundred and forty-eight CTLA4 mutation carriers have been reported; patients showed hypogammaglobulinemia, recurrent infectious diseases, various autoimmune diseases, and lymphocytic infiltration into multiple organs. The CTLA-4 expression level in Treg cells was reduced, while the frequency of Treg cells was increased in CTLA-4-insufficient patients. The transendocytosis assay is a specific functional test for the assessment of newly identified CTLA4 gene variants. Immunoglobulin substitution, corticosteroids, immunosuppressive therapy, and targeted therapy such as with CTLA-4 fusion proteins and mechanistic target of rapamycin (mTOR) inhibitors were applied; patients with life-threatening, treatment-resistant symptoms underwent hematopoietic stem cell transplantation. The fact that in humans CTLA-4 insufficiency causes severe disease taught us that the amount of CTLA-4 molecules present in/on T cells matters for immune homeostasis. However, whether the pathology-causing activated T lymphocytes in CTLA-4-insufficient patients are antigen-specific is an unsolved question. CTLA-4, in addition, has a role in autoimmune diseases and cancer. Anti-CTLA-4 drugs are employed as checkpoint inhibitors to target various forms of cancer. Thus, clinical research on human CTLA-4 insufficiency might provide us a deeper understanding of the mechanism(s) of the CTLA-4 molecule and immune dysregulation disorders.

Prevalence of immune-related adverse events and anti-tumor efficacy following immune checkpoint inhibitor therapy in Japanese patients with various solid tumors.

BACKGROUND: While immune checkpoint inhibitors (ICIs) occasionally cause immune-related adverse events (irAEs) in various organs, the prevalence of irAEs and potential risk factors have not been clarified. We identified irAE predictive factors and examined the relationship between the effect of ICIs and irAEs for patients with malignancies. METHODS: A total of 533 cases treated with ICIs, including programmed death 1 (PD-1), PD-ligand 1 (PD-L1), and cytotoxic T-lymphocyte antigen 4 (CTLA-4), for various malignancies were included retrospectively. We recorded irAEs from medical records and graded them using the Common Terminology Criteria for Adverse Events version 5. Prevalence and predictive factors associated with immune-related liver injury and the relationship between irAE and treatment response were analyzed. RESULTS: During a median of 10 (1-103) cycles with a median follow-up after several ICI initiations of 384 (21-1715) days, irAEs with all grades and with grade ≥ 3 developed in 144 (27.0%) and 57 (10.7%) cases. Cumulative irAE development rates were 21.9, 33.5, and 43.0% in all grades and 8.8, 14.9, and 20.7% in grade ≥ 3 at 5, 10, and 20 cycles, respectively. Patients who received anti-CTLA4 therapy were more likely to develop irAEs compared to those who received anti-PD-1 or anti-PD-L1 monotherapy. Liver injury was the most common irAE. Multivariate analysis identified the combination of PD-1 and anti-CTL-4 antibodies (hazard ratio [HR], 17.04; P < 0.0001) and baseline eosinophil count ≥130/µL (HR, 3.01 for < 130; P = 0.012) as independent risk factors for the incidence of immune-related liver injury with grade ≥ 2. Patients who developed irAEs had a higher disease control rate (P < 0.0001) and an increased overall survival rate compared to those without irAEs (P < 0.0001). CONCLUSION: Combination therapy with anti-PD-1 and anti-CTL-4 antibodies resulted in higher a frequency of irAEs. Baseline absolute eosinophil count was found to be a predictive factor for immune-related liver injury. Occurrence of irAEs may be associated with higher efficacy of ICI treatment and longer survival among patients who receive ICI therapy.

Prognostic implication of CTLA-4, PD-1, and PD-L1 expression in aggressive adult T-cell leukemia-lymphoma.

The prognosis of patients with aggressive adult T cell leukemia-lymphoma (ATLL) is dismal even with intensive chemotherapy. Allogeneic hematopoietic stem cell transplantation (HSCT) is a promising option for patients with aggressive ATLL, but the posttransplant outcome remains unsatisfactory. Hence, to further improve clinical outcomes, novel therapeutic approaches are needed. The clinical significance of immune checkpoint protein expression has not been well-established in aggressive ATLL. This study aims to identify the association between the expression profile of immune checkpoint proteins on ATLL cells and clinical outcomes. This retrospective study cohort included 65 patients with aggressive ATLL diagnosed between 2001 and 2015 at the National Cancer Center Hospital, Tokyo, Japan. Formalin-fixed paraffin-embedded tissue was used to immunohistochemically determine the expression of immune checkpoint proteins and assess the impact of expression profile on the probability of overall survival from diagnosis or HSCT. The current analysis shows that cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1) expressions were adverse prognostic factors in patients with aggressive ATLL. Experiments that assess the efficacy of immune checkpoint inhibitors are warranted to alleviate the adverse impacts associated with negative immune checkpoints.

Soluble cytotoxic T-lymphocyte-associated antigen 4 (sCTLA-4) as a potential biomarker for diagnosis and evaluation of the prognosis in Glioma.

BACKGROUND: The cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) is widely considered as a pivotal immune checkpoint molecule to suppress antitumor immunity. However, the significance of soluble CTLA-4 (sCTLA-4) remains unclear in the patients with brain glioma. Here we aimed to investigate the significance of serum sCTLA-4 levels as a noninvasive biomarker for diagnosis and evaluation of the prognosis in glioma patients. METHODS: In this study, the levels of sCTLA-4 in serum from 50 patients diagnosed with different grade gliomas including preoperative and postoperative, and 50 healthy individuals were measured by an enzyme-linked immunosorbent assay (ELISA). And then ROC curve analysis and survival analyses were performed to explore the clinical significance of sCTLA-4. RESULTS: Serum sCTLA-4 levels were significantly increased in patients with glioma compared to that of healthy individuals, and which was also positively correlated with the tumor grade. ROC curve analysis showed that the best cutoff value for sCTLA-4 for glioma is 112.1 pg/ml, as well as the sensitivity and specificity with 82.0 and 78.0%, respectively, and a cut-off value of 220.43 pg/ml was best distinguished in patients between low-grade glioma group and high-grade glioma group with sensitivity 73.1% and specificity 79.2%. Survival analysis revealed that the patients with high sCTLA-4 levels (> 189.64 pg/ml) had shorter progression-free survival (PFS) compared to those with low sCTLA-4 levels (≤189.64 pg/ml). In the univariate analysis, elder, high-grade tumor, high sCTLA-4 levels and high Ki-67 index were significantly associated with shorter PFS. In the multivariate analysis, sCTLA-4 levels and tumor grade remained an independent prognostic factor. CONCLUSION: These findings indicated that serum sCTLA-4 levels play a critical role in the pathogenesis and development of glioma, which might become a valuable predictive biomarker for supplementary diagnosis and evaluation of the progress and prognosis in glioma.

The role of cytotoxic T-Lymphocyte antigen-4+49A/G gene polymorphism in cutaneous leishmaniasis.

BACKGROUND: Cutaneous Leishmaniasis (CL) is a parasitic disease caused by intracellular protozoa belonging to the Leishmania genus. In endemic areas, only a proportion of exposed subjects develop the disease under almost similar circumstances, reflecting the role of genetic inheritance in resistance and susceptibility to infection. This study aimed To evaluate the association of cytotoxic T-lymphocyte antigen-4 (CTLA-4)+49G/A single nucleotide polymorphism (SNP) with incidence and severity of CL. METHODS: This cross-sectional study includes 110 patients with confirmed CL (60 newly diagnosed and 50 patients undergoing treatment) and 60 healthy subjects of similar age and sex. The CTLA-4 gene fragment corresponding to CTLA-4+49G/A polymorphism was amplified and genotyped using tetra primer amplification refractory mutation- polymerase chain reaction system (TARMS-PCR) methods. Soluble CTLA-4 (sCTLA-4) was estimated in the serum using an enzyme-linked immunosorbent assay (ELISA). RESULTS: The GG genotype of CTLA-4+49G/A polymorphism was significantly more common in controls than in patients (OR = 0.11, 95% CI = 0.02-0.58, p = 0.009). At allelic level, G allele was much more common in controls than in patients (30.83% vs. 17.73%) with a significant difference (OR = 2.07, 95% CI = 1.23-3.48, p = 0.006). However, there was no significant difference in the frequency of genotypes and alleles between newly diagnosed and treated patients. Median serum concentration of sCTLA-4 in newly diagnosed patients was 72.6 pg/ml (range 15.6-127 pg/ml) which was higher than either controls (median = 16.3 pg/ml, range 0.8-48.5 pg/ml) or treated patients (median = 17.9 pg/ml, range 2.9-74.7 pg/ml) with highly significant differences, while there was no significant difference between controls and treated patients. The median sCTLA-4 level was comparable across genotypes of the CTLA-4+49G/A polymorphism, with no significant difference. CONCLUSIONS: Collectively, these results show the protective role of allele G of the SNP CTLA-4+49G/A against CL and increased serum sCTLA-4 in newly diagnosed CL patients, which may be used as an additional diagnostic tool. Different genotypes of the CTLA-4+49G/A polymorphism have no effect on sCLTA-4 serum levels.

A CTLA-4 blocking strategy based on Nanoboby in dendritic cell-stimulated cytokine-induced killer cells enhances their anti-tumor effects.

BACKGROUND: Cytokine-induced killer cells induced with tumor antigen-pulsed dendritic cells (DC-CIK) immunotherapy is a promising strategy for the treatment of malignant tumors. However, itsefficacy isrestricted by the immunosuppression, which is mediated by the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) pathway. In order to overcome the negative co-stimulation from these T cells,we screened a nanobody targeted for CTLA-4 (Nb36) and blocked the CTLA-4 signaling with Nb36. METHODS: Peripheral blood mononuclear cells (PBMCs) were collected from healthy donors to beused to induce CIK cells in vitro, after which they were co-cultured with DC cells that had received tumor antigens. In addition, wetested whether blocking CTLA-4 signaling with Nb36 could promote in vitro DC-CIK cells proliferation, pro-inflammatory cytokine production and cytotoxicity,or not. For the in vivo experiments, we constructed a subcutaneously transplanted tumor model and placed it in NOD/SCID mice to verify the anti-tumor effect of this therapy. RESULTS: After stimulation with Nb36, the DC-CIK cells presented enhanced proliferation and production of IFN-γ in vitro, which strengthened the killing effect on the tumor cells. For the in vivo experiments, it was found that Nb36-treated DC-CIK cells significantly inhibited the growth of subcutaneously transplanted livercancer tumors, as well as reduced the tumor weight and prolonged the survival of tumor-bearing NOD/SCID mice. CONCLUSIONS: Ourfindings demonstrated that in response to CTLA-4 specific nanobody stimulation, DC-CIK cells exhibited a better anti-tumor effect. In fact, this Nb-based CTLA-4 blocking strategy achieved an anti-tumor efficacy close to that of monoclonal antibodies. Our findings suggest that DC-CIK cells + Nb36 have the potential totreatmalignant tumors through in vivo adoptive therapy.

Addressing resistance to immune checkpoint inhibitor therapy: an urgent unmet need.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of various cancers by reversing the immunosuppressive mechanisms employed by tumors to restore anticancer immunity. Although ICIs have demonstrated substantial clinical efficacy, patient response can vary in depth and duration, and many do not respond at all or eventually develop resistance. ICI resistance mechanisms can be tumor-intrinsic, related to the tumor microenvironment or patient-specific factors. Multiple resistance mechanisms may be present within one tumor subtype, or heterogeneity exists among patients with the same tumor type. Consequently, designing effective combination treatment strategies is challenging. This review will discuss ICI resistance mechanisms, and summarize findings from key preclinical and clinical trials of ICIs, to identify potential treatment strategies or pathways to overcome ICI resistance.

Endocrine adverse effects of immune checkpoint inhibitors.

Immune checkpoint inhibitors are increasingly being utilised as an effective therapy for a variety of cancers. However, they have the potential to cause serious autoimmune toxicities in multiple organ systems termed 'immunotherapy-related adverse events'. Endocrine toxicities are common, can occur well after commencement of therapy and can result in significant morbidity and mortality if not recognised. This makes it important for all physicians, in addition to endocrinologists and oncologists, to understand the nature of these reactions and the general approach to their diagnosis and management. This review aims to provide an overview of the epidemiology, pathophysiology, clinical presentation and management of the endocrine adverse events.

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Over the past decade, immunotherapy has been shown to have antitumor activity in a variety of solid tumors, such as melanoma, renal cell carcinoma, and non-small cell lung cancer, keeping a lead in a new era of tumor immunotherapy. Colorectal cancer with high microsatellite instability (MSI-H) or mismatch repair deficient (dMMR) is sensitive to immune checkpoint inhibitors (ICIs). ICIs monotherapy and ICIs combination therapy have made breakthroughs in the treatment of MSI-H/dMMR CRC. At present, a variety of ICIs have been approved for first- and post-line treatment in patients with CRC. However, MSI-H/dMMR type tumors only account for 5% of metastatic CRC, and the most CRCs were microsatellite stable (MSS) or mismatch repair proficient (pMMR). Many clinical trials are exploring effective treatments for patients with MSS/pMMR CRC, and the combination of ICIs and drugs with different mechanisms is expected to improve the efficacy of MSS/pMMR CRC patients. In the future, attention should be paid to finding the potential therapeutic markers of ICIs and the drug resistance mechanism of ICIs, so as to break through the immune tolerance of MSS/pMMR CRC patients.

Clinical outcomes of solid organ transplant recipients with metastatic cancers who are treated with immune checkpoint inhibitors: A single-center analysis.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy, but to the authors' knowledge, limited data exist regarding the safety and efficacy of these agents in transplant recipients. Herein, the authors have reported their experience with 17 patients who were treated with ICIs for metastatic malignancies after undergoing solid organ transplantation. METHODS: Data were abstracted for solid organ transplant recipients who received ICIs for the treatment of malignancy between January 1, 2016, and September 30, 2019. The authors identified 7 kidney, 8 liver, and 2 heart transplant recipients. Outcomes of interest were adverse drug reactions, cancer progression, and patient survival. RESULTS: The most common malignancies treated with ICIs were metastatic squamous cell carcinoma (5 patients; 29%) and hepatocellular carcinoma (5 patients; 29%), which were noted exclusively among liver transplant recipients. The median duration on ICIs was 1.7 months (interquartile range, 0.4-7.6 months). Five patients (29%) developed adverse reactions, including 4 patients (24%) with immune-related adverse events(irAEs), 3 patients (18%) with acute allograft rejections, 1 patient (6%) with autoimmune colitis, and 1 patient (6%) with ICI-induced cardiotoxicity (the patient was a heart transplant recipient). The cumulative incidence of cancer progression was 50% and 69%, respectively, at 6 months and 12 months. Eleven patients (65%) died over the median follow-up period of 4.6 months (interquartile range, 1.5-13.2 months) from the time of ICI initiation, with cancer progression being the most common cause of death. CONCLUSIONS: ICIs can be used as individualized therapy in selected patients who have undergone solid organ transplantation but more studies are needed to determine how best to use these agents to improve outcomes further.

Evolving insights into the mechanisms of toxicity associated with immune checkpoint inhibitor therapy.

Immune checkpoint inhibitors have emerged as a revolutionary treatment option for patients with various types of malignancy. Although these agents afford a significant improvement in outcomes for melanoma and other previously untreatable malignancies, their novel mechanism of action may predispose patients to immune-related adverse effects (irAEs). In the tumour neoantigen environment, these irAEs are due to the activation of the immune system by the blockade of suppressive checkpoints, leading to increases in T-cell activation and proliferation. IrAEs have been reported in almost any organ and at any point in time, even months to years after discontinuation of therapy. Certain populations with distinct physiological changes, genetic risk factors, and specific antigen exposures may be more highly predisposed to develop irAEs. This review discusses the incidence and mechanisms of irAEs and the relationship between host factors and irAE occurrence.

Translational Biomarkers and Rationale Strategies to Overcome Resistance to Immune Checkpoint Inhibitors in Solid Tumors.

Immune checkpoint inhibitors (ICIs) targeting the programed cell-death protein 1 (PD-1) or its ligand PD-L1 and cytotoxic T-lymphocyte antigen 4 (CTLA-4) pathways have improved the survival for patients with solid tumors. Unfortunately, durable clinical responses are seen in only 10-40% of patients at the cost of potential immune-related adverse events. In the tumor microenvironment (TME), tumor cells can influence the microenvironment by releasing extracellular signals and generating peripheral immune tolerance, while the immune cells can affect the initiation, growth, proliferation, and evolution of cancer cells. Currently, translational biomarkers that predict responses to ICIs include high PD-L1 tumor proportion score, defective DNA mismatch repair, high microsatellite instability, and possibly high tumor mutational burden. Characterization of immune cells in the TME, such as tumor-infiltrating lymphocytes, T-cell gene expression profile, T-cell receptor sequencing, and peripheral blood biomarkers are being explored as promising biomarkers. Recent neoadjuvant studies have integrated the real-time assessment of both molecular and immune biomarkers using the tissue and blood specimens simultaneously and longitudinally. This review summarizes the current knowledge and progress in developing translational biomarkers and rational combinational strategies to improve the efficacy of ICIs tailored to individual cancer patients.

CTLA-4 and HLA-DQ are key molecules in the regulation of mDC-mediated cellular immunity by Tregs in severe aplastic anemia.

BACKGROUND: Regulatory T cells (Tregs) inhibit the activation of cluster of differentiation (CD) 4+ , CD8+ T cells and the antigen-presenting process of antigen-presenting cells, and may play an important role in acquired severe aplastic anemia (SAA). METHODS: Flow cytometry was used to measure CD4+ CD25+ CD127dim Tregs, cytotoxic T lymphocyte antigen 4 (CTLA-4) expression on Tregs, and human leukocyte antigen (HLA)-DQ expression on myeloid dendritic cells (mDCs). The correlations of CTLA-4 and HLA-DQ with immune status and clinical indicators and the changes in these indicators after immunosuppressive therapy (IST) were analyzed. RESULTS: In SAA patients, the number of Tregs and their CTLA-4 expression were low but recovered after IST; the HLA-DQ expression on mDCs was high but decreased after IST. The CTLA-4 expression on Tregs and the HLA-DQ expression on mDCs showed a negative correlation. The CTLA-4 on Tregs was positively but HLA-DQ on mDCs negatively correlated with the number of Tregs, natural killer (NK) cell number, and CD4+ T/CD8+ T ratio. CTLA-4 was positively but HLA-DQ negatively correlated with the percentage of granulocytoid and erythroid cells in bone marrow, white blood cell count in PB, absolute neutrophil count in PB, and the percentage of reticulocytes in PB. CONCLUSIONS: CTLA-4/HLA-DQ may be key in the regulation of Tregs on mDCs in SAA patients. Our findings should be helpful for further investigation of the mechanism of immune pathogenesis in SAA patients. Studies on the regulators of Treg and CTLA-4 activity will be valuable for SAA therapeutic target research and disease monitoring.