Role of PD-L1 and PD-L2 in allergic diseases and asthma

Pembrolizumab-induced asthma exacerbation with hypereosinophilia and elevated interleukin-5 in endometrial cancer: A case report

Pembrolizumab is an anti-programmed cell death-1 (PD-1) antibody used to treat various cancer types. Treatments with such immune checkpoint inhibitors cause immune-related adverse events. However, airway inflammation caused by immune-related adverse events has rarely been reported. A 54-year-old woman with endometrial cancer experienced asthma exacerbation, and increased blood eosinophil counts 3 months after pembrolizumab administration. Although asthma exacerbation improved, the resumption of pembrolizumab caused the recurrence of dry cough and hypereosinophilia. The discontinuation of pembrolizumab improved her symptoms. Serum interleukin-5 levels increased during pembrolizumab treatment but decreased upon discontinuation. The blockade of PD-1 and its ligand may exacerbate asthma through eosinophilic inflammation.

The occurrence of asthma in an extensive-stage small-cell lung cancer patient after combination therapy with atezolizumab and anlotinib: a case report

Background

Extensive-stage small-cell lung cancer (ES-SCLC) is highly malignant, with early metastasis and high recurrence. Since therapeutic options are limited, ES-SCLC has a characteristically short survival period and extremely poor prognosis. A combination of immune checkpoint inhibitors (ICIs) and anti-angiogenic drugs can achieve promising efficacy and safety in patients with ES-SCLC as a second-line or subsequent treatment, extending survival to some extent. However, the clinical outcomes remain mostly unsatisfactory and are sometimes affected by treatment-related adverse events.

Case presentation

A 57-year-old woman with ES-SCLC was administered a combination therapy of atezolizumab (a PD-L1 inhibitor) and anlotinib [an oral multi-targeted tyrosine kinase inhibitor (TKI)]. She survived for 22 months, with no disease progression during the 28 courses of therapy. Unexpectedly, despite having no history of asthma, the patient developed asthma while receiving this regimen. This is possibly related to T-cell activation and the tumor immune microenvironment, which induce allergic inflammation after PD-L1 blockade.

Conclusions

This is the first report of an asthma-negative ES-SCLC patient who developed asthma after receiving atezolizumab plus anlotinib. Although this combination therapy may effectively extend survival in SCLC patients, asthmatic symptoms should be closely monitored.

Genomic Profiling Reveals Immune-Related Gene Differences in Lung Cancer Patients Stratified by PD1/PDL1 Expression: Implications for Immunotherapy Efficacy

Lung cancer remains a leading cause of global cancer-related mortality, and the exploration of innovative therapeutic approaches, such as PD1/PDL1 immunotherapy, is critical. This study leverages comprehensive data from the Cancer Genome Atlas (TCGA) to investigate the differential expression of PD1/PDL1 in lung cancer patients and explores its implications. Clinical data, RNA expression, somatic mutations, and copy number variations of 1017 lung cancer patients were obtained from TCGA. Patients were categorized into high (HE) and low (LE) PD1/PDL1 expression groups based on mRNA levels. Analyses included differential gene expression, functional enrichment, protein-protein interaction networks, and mutational landscape exploration. The study identified 391 differentially expressed genes, with CD4 and PTPRC among the upregulated genes in the HE group. Although overall survival did not significantly differ between HE and LE groups, enrichment analysis revealed a strong association with immunoregulatory signaling pathways, emphasizing the relevance of PD1/PDL1 in immune response modulation. Notably, TP53 mutations were significantly correlated with high PD1/PDL1 expression. This study provides a comprehensive analysis of PD1/PDL1 expression in lung cancer, uncovering potential biomarkers and highlighting the intricate interplay between PD1/PDL1 and the immune response. The identified upregulated genes, including CD4 and PTPRC, warrant further investigation for their roles in the context of lung cancer and immunotherapy. The study underscores the importance of considering molecular heterogeneity in shaping personalized treatment strategies for lung cancer patients. Limitations, such as the retrospective nature of TCGA data, should be acknowledged.

The therapeutic potential of PD-1/PD-L1 pathway on immune-related diseases: Based on the innate and adaptive immune components

Currently, immunotherapy targeting programmed cell death 1 (PD-1) or programmed death ligand 1 (PD-L1) has revolutionized the treatment strategy of human cancer patients. Meanwhile, PD-1/PD-L1 pathway has also been implicated in the pathogenesis of many immune-related diseases, such as autoimmune diseases, chronic infection diseases and adverse pregnancy outcomes, by regulating components of the innate and adaptive immune systems. Given the power of the new therapy, a better understanding of the regulatory effects of PD-1/PD-L1 pathway on innate and adaptive immune responses in immune-related diseases will facilitate the discovery of novel biomarkers and therapeutic drug targets. Targeting this pathway may successfully halt or potentially even reverse these pathological processes. In this review, we discuss recent major advances in PD-1/PD-L1 axis regulating innate and adaptive immune components in immune-related diseases. We reveal that the impact of PD-1/PD-L1 axis on the immune system is complex and manifold and multi-strategies on the targeted PD-1/PD-L1 axis are taken in the treatment of immune-related diseases. Consequently, targeting PD-1/PD-L1 pathway, alone or in combination with other treatments, may represent a novel strategy for future therapeutic intervention on immune-related diseases.

Immunomodulatory effects of nanoparticles on dendritic cells in a model of allergic contact dermatitis: importance of PD-L2 expression

Nanoparticle (NP) skin exposure is linked to an increased prevalence of allergic contact dermatitis. In our prior studies using the mouse contact hypersensitivity (CHS) model, we reported that silica 20 nm (SiO2) NPs suppressed the allergic response and titanium dioxide NPs doped with manganese (mTiO2) exacerbated it. In this work, we conducted in vitro experiments using bone marrow-derived dendritic cells (BMDCs) to study the combinatorial effect of the potent 2,4-dinitrofluorobenzene (DNFB) hapten sensitizer with SiO2 and mTiO2 NPs on BMDC cytotoxicity, cytokine secretion and phenotype using the B7 family ligands. Results show that DNFB and mTiO2 behave similarly and exhibit proinflammatory characteristics while SiO2 promotes a naive phenotype. We observe that the B7-H3 (CD276) ligand is only expressed on CD80 + (B7-1) BMDCs. Results from adoptive transfer CHS studies, combined with BMDC phenotype analysis, point to the importance of PD-L2 expression in modulating the adaptive immune response. This work identifies metrics that can be used to predict the effects of NPs on contact allergy and to guide efforts to engineer cell-based therapies to induce hapten specific immune tolerance.

Immunomodulatory Effects of Nanoparticles on Dendritic Cells in a Model of Allergic Contact Dermatitis - Importance of PD-L2 Expression

Nanoparticle (NP) skin exposure is linked to the increased prevalence of allergic contact dermatitis. In prior studies using the mouse contact hypersensitivity (CHS) model, we reported that silica 20 nm (Si20nm) suppressed the allergic response and TiO2 doped with manganese (mTiO2) exacerbated it. In this work, we conducted in vitro experiments using bone marrow-derived dendritic cells (BMDCs) to study the combinatorial effect of the potent 2, 4-dinitrofluorobenzene (DNFB) hapten sensitizer with Si20nm and mTiO2 NPs on BMDC cytotoxicity, cytokine secretion and phenotype using the B7 family ligands. Results show that DNFB and mTiO2 behave similarly and exhibit proinflammatory characteristics while Si20nm promotes a naive phenotype. We observe that the B7-H3 (CD276) ligand is only expressed on CD80+ (B7-1) BMDC. Results from adoptive transfer CHS studies, combined with BMDC phenotype analysis, point to the importance of PD-L2 expression in modulating the adaptive immune response. This work identifies metrics that can be used to predict the effects of NPs on contact allergy and to guide efforts to engineer cell-based therapies to induce antigen specific immune tolerance.

The role of PD-1 signaling in health and immune-related diseases

Programmed cell death 1 receptor (PD-1) and its ligands constitute an inhibitory pathway to mediate the mechanism of immune tolerance and provide immune homeostasis. Significantly, the binding partners of PD-1 and its associated ligands are diverse, which facilitates immunosuppression in cooperation with other immune checkpoint proteins. Accumulating evidence has demonstrated the important immunosuppressive role of the PD-1 axis in the tumor microenvironment and in autoimmune diseases. In addition, PD-1 blockades have been approved to treat various cancers, including solid tumors and hematological malignancies. Here, we provide a comprehensive review of the PD-1 pathway, focusing on the structure and expression of PD-1, programmed cell death 1 ligand 1 (PD-L1), and programmed cell death 1 ligand 2 (PD-L2); the diverse biological functions of PD-1 signaling in health and immune-related diseases (including tumor immunity, autoimmunity, infectious immunity, transplantation immunity, allergy and immune privilege); and immune-related adverse events related to PD-1 and PD-L1 inhibitors.

Human PD-1 agonist treatment alleviates neutrophilic asthma by reprogramming T cells

BACKGROUND

Neutrophilic asthma is associated with disease severity and corticosteroid insensitivity. Novel therapies are required to manage this life-threatening asthma phenotype. Programmed cell death protein-1 (PD-1) is a key homeostatic modulator of the immune response for T-cell effector functions.

OBJECTIVE

We sought to investigate the role of PD-1 in the regulation of acute neutrophilic inflammation in a murine model of airway hyperreactivity (AHR).

METHODS

House dust mite was used to induce and compare neutrophilic AHR in wild-type and PD-1 knockout mice. Then, the therapeutic potential of a human PD-1 agonist was tested in a humanized mouse model in which the PD-1 extracellular domain is entirely humanized. Single-cell RNA sequencing and flow cytometry were mainly used to investigate molecular and cellular mechanisms.

RESULTS

PD-1 was highly induced on pulmonary T cells in our inflammatory model. PD-1 deficiency was associated with an increased neutrophilic AHR and high recruitment of inflammatory cells to the lungs. Consistently, PD-1 agonist treatment dampened AHR, decreased neutrophil recruitment, and modulated cytokine production in a humanized PD-1 mouse model. Mechanistically, we demonstrated at the transcriptional and protein levels that the inhibitory effect of PD-1 agonist is associated with the reprogramming of pulmonary effector T cells that showed decreased number and activation.

CONCLUSIONS

PD-1 agonist treatment is efficient in dampening neutrophilic AHR and lung inflammation in a preclinical humanized mouse model.

Immune checkpoint molecules in prevention and development of asthma

Allergic asthma is a respiratory disease initiated by type-2 immune responses characterized by secretion of alarmins, interleukin-4 (IL-4), IL-5, and IL-13, eosinophilic inflammation, and airway hyperresponsiveness (AHR). Immune checkpoints (ICPs) are inhibitory or stimulatory molecules expressed on different immune cells, tumor cells, or other cell types that regulate immune system activation and maintain immune homeostasis. Compelling evidence indicates a key role for ICPs in both the progression and prevention of asthma. There is also evidence of asthma development or exacerbation in some cancer patients receiving ICP therapy. The aim of this review is to provide an updated overview of ICPs and their roles in asthma pathogenesis, and to assess their implications as therapeutic targets in asthma.

Airway disorders associated with immune checkpoint inhibitor therapy: Two case reports and a systematic review

Immune checkpoint inhibitors (ICI) are widely used for the treatment of various malignant neoplasms. Interstitial lung disease is a well-known immune-related adverse event, however, ICI-induced airway disease remains under-recognized. Herein, we report two similar cases of pembrolizumab-induced tracheobronchitis presenting as persistent chronic cough and dyspnea. Blood tests revealed elevated C-reactive protein levels without eosinophilia. Spirometry demonstrated mild airflow obstruction. Computed tomography revealed diffuse thickening of the tracheobronchial walls and bronchiectasis predominantly in the lower lobes. Bronchoscopy revealed edematous and erythematous tracheobronchial mucosa, and bronchial biopsy tissue exhibited marked inflammation with predominant infiltration of CD8+ lymphocytes. Subsequently, pembrolizumab-induced tracheobronchitis was diagnosed in both cases. Cessation of pembrolizumab and initiation of erythromycin, inhaled corticosteroids, and long-acting beta-agonists gradually improved the symptoms, airflow obstruction, and radiographic findings. These were completely resolved in one case. The other case initially showed a poor response to systemic corticosteroids combined with the aforementioned drugs, but improved gradually and almost completely. These cases exemplify ICI-induced airway disease that is, an under-recognized manifestation of immune-related adverse events. In addition, we have systematically searched the PubMed database for articles on ICI-induced airway disease, categorized the retrieved articles as eosinophilic and non-eosinophilic airway diseases, and reviewed the differences in treatment and prognoses between these two categories.

Mobilisation of HLA-F on the surface of bronchial epithelial cells and platelets in asthmatic patients

Uncontrolled inflammation of the airways in chronic obstructive lung diseases leads to exacerbation, accelerated lung dysfunction and respiratory insufficiency. Among these diseases, asthma affects 358 million people worldwide. Human bronchial epithelium cells (HBEC) express both anti-inflammatory and activating molecules, and their deregulated expression contribute to immune cell recruitment and activation, especially platelets (PLT) particularly involved in lung tissue inflammation in asthma context. Previous results supported that HLA-G dysregulation in lung tissue is associated with immune cell activation. We investigated here HLA-F expression, reported to be mobilised on immune cell surface upon activation and displaying its highest affinity for the KIR3DS1-activating NK receptor. We explored HLA-F transcriptional expression in HBEC; HLA-F total expression in PBMC and HBEC collected from healthy individuals at rest and upon chemical activation and HLA-F membrane expression in PBMC, HBEC and PLT collected from healthy individuals at rest and upon chemical activation. We compared HLA-F transcriptional expression in HBEC from healthy individuals and asthmatic patients and its surface expression in HBEC and PLT from healthy individuals and asthmatic patients. Our results support that HLA-F is expressed by HBEC and PLT under healthy physiological conditions and is retained in cytoplasm, barely expressed on the surface, as previously reported in immune cells. In both cell types, HLA-F reaches the surface in the inflammatory asthma context whereas no effect is observed at the transcriptional level. Our study suggests that HLA-F surface expression is a ubiquitous post-transcriptional process in activated cells. It may be of therapeutic interest in controlling lung inflammation.

Noncoding RNAs and Virus and Treatment in Allergic Rhinitis

Allergic rhinitis (AR) is a type I hypersensitivity reaction disease caused by inhaled allergens and immunoglobulin E (IgE)-mediated. Noncoding RNA (ncRNA) is an important regulator involved in gene expression and can be detected in the cytoplasm or extracellular fluid, which mainly includes microRNAs (miRNA, length 22-24 nucleotides), long noncoding RNAs (lncRNA, length >200 nucleotides), and circRNAs. LncRNA and miRNA both participate in the regulation of immune function. Some respiratory viral infections can aggravate allergic rhinitis, such as a respiratory syncytial virus (RSV) and human metapneumovirus (hMPV). However, the interaction between viral infection and allergy is complex and the mechanism is still unclear. In this review, we summarized the interactions of noncoding RNAs and viruses in the occurrence and development of AR, along with the treatments focusing on the noncoding RNAs in the past five years.

PD-L2 controls peripherally induced regulatory T cells by maintaining metabolic activity and Foxp3 stability

Regulatory T (Treg) cells are central to limit immune responses to allergens. Here we show that PD-L2 deficiency prevents the induction of tolerance to ovalbumin and control of airway hyperreactivity, in particular by limiting pTreg numbers and function. In vitro, PD-1/PD-L2 interactions increase iTreg numbers and stability. In mice lacking PD-L2 we find lower numbers of splenic pTregs at steady state, producing less IL-10 upon activation and with reduced suppressive activity. Remarkably, the numbers of splenic pTregs are restored by adoptively transferring PD-L2high dendritic cells to PD-L2KO mice. Functionally, activated pTregs lacking PD-L2 show lower Foxp3 expression, higher methylation of the Treg-Specific Demethylation Region (TSDR) and a decreased Tricarboxylic Acid (TCA) cycle associated with a defect in mitochondrial function and ATP production. Consequently, pyruvate treatment of PD-L2KO mice partially restores IL-10 production and airway tolerance. Together, our study highlights the importance of the PD-1/PD-L2 axis in the control of metabolic pathways regulating pTreg Foxp3 stability and suppressive functions, opening up avenues to further improve mucosal immunotherapy.

Beyond Cancer: Regulation and Function of PD-L1 in Health and Immune-Related Diseases

Programmed Cell Death 1 Ligand 1 (PD-L1, CD274, B7-H1) is a transmembrane protein which is strongly involved in immune modulation, serving as checkpoint regulator. Interaction with its receptor, Programmed Cell Death Protein 1 (PD-1), induces an immune-suppressive signal, which modulates the activity of T cells and other effector cells. This mediates peripheral tolerance and contributes to tumor immune escape. PD-L1 became famous due to its deployment in cancer therapy, where blockage of PD-L1 with the help of therapeutic antagonistic antibodies achieved impressive clinical responses by reactivating effector cell functions against tumor cells. Therefore, in the past, the focus has been placed on PD-L1 expression and its function in various malignant cells, whereas its role in healthy tissue and diseases apart from cancer remained largely neglected. In this review, we summarize the function of PD-L1 in non-cancerous cells, outlining its discovery and origin, as well as its involvement in different cellular and immune-related processes. We provide an overview of transcriptional and translational regulation, and expression patterns of PD-L1 in different cells and organs, and illuminate the involvement of PD-L1 in different autoimmune diseases as well as in the context of transplantation and pregnancy.

Plasma extracellular vesicle derived protein profile predicting and monitoring immunotherapeutic outcomes of gastric cancer

Immune checkpoint inhibitor (ICI)‐based immunotherapy brought new hope for gastric cancer (GC) treatment. However, due to the lack of proper biomarkers, patient selection and outcome prediction for GC's immunotherapy remain unsatisfying. In this study, through applying an extracellular vesicle (EV) protein expression array, we assessed the correlation of plasma EV‐derived protein spectrum with outcomes of ICI‐related therapeutic combinations. Plasma from 112 GC patients received ICI‐related therapies were investigated retrospectively/prospectively as three cohorts. We identified four plasma EV‐derived proteins (ARG1/CD3/PD‐L1/PD‐L2) from 42 crucial candidate proteins and combined them as an EV‐score that robustly predicting immunotherapeutic outcomes at baseline and dynamically monitoring disease progression along with treatment. High EV‐score reflected microenvironmental features of stronger antitumour immunity, characterized by more activated CD8⁺ T/NK cells, higher TH1/TH2 ratio and higher expressions of IFN‐γ/perforin/granzymes in paired peripheral blood, which were verified by dataset analysis and in vivo experiments. EV‐score≥1 GC received more therapeutic benefits from ICIs, while EV‐score < 1 GC potentially benefited more from ICIs combining HER2‐targeted therapies. Collectively, through proposing a plasma EV‐score on protein level that powerfully predicting and monitoring GC's immunotherapeutic outcomes, our work facilitated clinical patient selection and decision‐makings, and provided mechanistical insights for immunotherapy‐related microenvironmental changes and improvements for current ICI‐regimens.

Role of IL-18-transformed CD274-expressing eosinophils in promoting airway obstruction in experimental asthma

BACKGROUND

IL-5-dependent residential and IL-18-transformed pathogenic eosinophils have been reported; however, the role of IL-18-transformed CD274-expressing pathogenic eosinophils compared to IL-5-generated eosinophils in promoting airway obstruction in asthma has not yet been examined.

METHODS

Eosinophils are detected by tissue anti-MBP and anti-EPX immunostaining, CD274 expression by flow cytometry, and airway resistance using the Buxco FinePointe RC system.

RESULTS

We show that A. fumigatus-challenged wild-type mice, and different gene-deficient mice including naïve CC10-IL-18-transgenic mice, accumulate mostly peribronchial and perivascular CD274-expressing eosinophils except naïve CD2-IL-5-transgenic mice. Additionally, we show that CD2-IL-5 transgenic mice following rIL-18 treatment accumulate high number of CD274-expressing perivascular and peribronchial eosinophils with induced collagen, goblet cell hyperplasia and airway resistance compared to saline-challenged CD2-IL5 transgenic mice. Furthermore, we also show that even A. fumigatus-challenged IL-5 ^-/- mice and rIL-18 given ΔdblGATA mice accumulate CD274-expressing eosinophil-associated asthma pathogenesis including airway obstruction. Most importantly, we provide evidence that neutralization of CD274 and IL-18 in A. fumigatus-challenged mice ameliorate experimental asthma. Taken together, the data presented are clinically significant in establishing that anti-IL-18 neutralization is a novel immunotherapy to restrict asthma pathogenesis.

CONCLUSIONS

We demonstrate that IL-18 is critical for inducing asthma pathogenesis, and neutralization of CD274 is a potential immunotherapeutic strategy for asthma.

New Insights into the Role of PD-1 and Its Ligands in Allergic Disease

Programmed cell death 1 (PD-1) and its ligands PD-L1 and PD-L2 are receptors that act in co-stimulatory and coinhibitory immune responses. Signaling the PD-1/PD-L1 or PD-L2 pathway is essential to regulate the inflammatory responses to infections, autoimmunity, and allergies, and it has been extensively studied in cancer. Allergic diseases include asthma, rhinoconjunctivitis, atopic dermatitis, drug allergy, and anaphylaxis. These overactive immune responses involve IgE-dependent activation and increased CD4+ T helper type 2 (Th2) lymphocytes. Recent studies have shown that PD-L1 and PD-L2 act to regulate T-cell activation and function. However, the main role of PD-1 and its ligands is to balance the immune response; however, the inflammatory process of allergic diseases is poorly understood. These immune checkpoint molecules can function as a brake or a kick-start to regulate the adaptive immune response. These findings suggest that PD-1 and its ligands may be a key factor in studying the exaggerated response in hypersensitivity reactions in allergies. This review summarizes the current understanding of the role of PD-1 and PD-L1 and PD-L2 pathway regulation in allergic diseases and how this immunomodulatory pathway is currently being targeted to develop novel therapeutic immunotherapy.

Parameters of Tumor Microenvironment Determine Effectiveness of Anti-PD-1/PD-L1 Therapy

Undoubtedly, one of the most promising approaches to the treatment of cancer is creation of the pathogenetically based therapeutic drugs. Researchers from all over the world are trying to answer the question on how to select a target that would be effective and, in general, they are quite successful at that. The Nobel Prize-winning discovery of mechanisms for regulating activity of the immune system cells through checkpoint molecules, as well as discovery of the ability of tumor cells to use these mechanisms to suppress immune responses was an impetus for the development of modern immunotherapy, and now such inhibitors of the immune checkpoints as PD-1/PD-L1 are included in the routine chemotherapy. Use of such drugs can prolong the patient's life, but, unfortunately, not cure the disease. This is partially due to heterogeneity of tumor cells and microenvironment, but the main reasons may be in the complex relationships between the tumor and microenvironment, which, at times, are so plastic that they can change, adjusting to newly emerging conditions. Main characteristic of the tumor microenvironment is the type of the ongoing immune-inflammatory response (IIR), and since inhibitors of the immune checkpoints act on the cells involved in IIR, it is obvious that the outcomes of cancer therapy, including outcomes of hyperprogressive disease, can be associated with this parameter. The presented review reveals the essence of interactions between the tumor and its microenvironment during therapy with PD-L1 inhibitors.

Gram-negative microbiota is related to acute exacerbation in children with asthma

BACKGROUND

The upper-airway microbiota may be associated with the pathogenesis of asthma and useful for predicting acute exacerbation. However, the relationship between the lower-airway microbiota and acute exacerbation in children with asthma is not well understood. We evaluated the characteristics of the airway microbiome using induced sputum from children with asthma exacerbation and compared the microbiota-related differences of inflammatory cytokines with those in children with asthma.

METHODS

We analysed the microbiome using induced sputum during acute exacerbation of asthma in children. We identified microbial candidates that were prominent in children with asthma exacerbation and compared them with those in children with stable asthma using various analytical methods. The microbial candidates were analysed to determine their association with inflammatory cytokines. We also developed a predictive functional profile using PICRUSt.

RESULTS

A total of 95 children with allergic sensitisation including 22 with asthma exacerbation, 67 with stable asthma, and 6 controls were evaluated. We selected 26 microbial candidates whose abundances were significantly increased, decreased, or correlated during acute exacerbation in children with asthma. Among the microbial candidates, Campylobacter, Capnocytophaga, Haemophilus, and Porphyromonas were associated with inflammatory cytokines including macrophage inflammatory protein (MIP)-1β, programmed death-ligand 1, and granzyme B. Both Campylobacter and MIP-1β levels were correlated with sputum eosinophils. Increased lipopolysaccharide biosynthesis and decreased glycan degradation were observed in children with asthma exacerbation.

CONCLUSION

Gram-negative microbes in the lower airway were related to acute exacerbation in children with asthma. These microbes and associated cytokines may play a role in exacerbating asthma in children.

Adiponectin and Asthma: Knowns, Unknowns and Controversies

Adiponectin is an adipokine associated with the healthy obese phenotype. Adiponectin increases insulin sensitivity and has cardio and vascular protection actions. Studies related to adiponectin, a modulator of the innate and acquired immunity response, have suggested a role of this molecule in asthma. Studies based on various asthma animal models and on the key cells involved in the allergic response have provided important insights about this relation. Some of them indicated protection and others reversed the balance towards negative effects. Many of them described the cellular pathways activated by adiponectin, which are potentially beneficial for asthma prevention or for reduction in the risk of exacerbations. However, conclusive proofs about their efficiency still need to be provided. In this article, we will, briefly, present the general actions of adiponectin and the epidemiological studies supporting the relation with asthma. The main focus of the current review is on the mechanisms of adiponectin and the impact on the pathobiology of asthma. From this perspective, we will provide arguments for and against the positive influence of this molecule in asthma, also indicating the controversies and sketching out the potential directions of research to complete the picture.

Prognostic prospect of soluble programmed cell death ligand-1 in cancer management

Aggressive tissue biopsy is commonly unavoidable in the management of most suspected tumor cases to conclusively verify the presence of cancerous cells through histological assessment. The extracted tissue is also immunostained for detection of antigens (tissue tumor markers) of potential prognostic or therapeutic importance to assist in treatment decision. Although liquid biopsies can be a powerful tool for monitoring treatment response, they are still excluded from standard cancer diagnostics, and their utility is still being debated in the scientific community. With a myriad of soluble tissue tumor markers now being discovered, liquid biopsies could completely change the current paradigms of cancer management. Recently, soluble programmed cell death ligand-1 (sPD-L1), which is found in the peripheral blood, i.e. serum and plasma, has shown potential as a pre-therapeutic predictive marker as well as a prognostic biomarker to monitor treatment efficacy. Thus, this review focuses on the emergence of sPD-L1 and promising technologies for its detection in order to support liquid biopsies for future cancer management.

PD-L1 Blockade During Allergen Sensitization Inhibits the Synthesis of Specific Antibodies and Decreases Mast Cell Activation in a Murine Model of Active Cutaneous Anaphylaxis

Programmed cell death ligand 1(PDL-1) is known for its inhibitory effect on the cellular immune response. Even though it is expressed on the surface of mast cells, its role in allergic diseases is unknown. We analyzed the effects of PD-L1 blockade in a murine model of active cutaneous anaphylaxis (ACA). C57BL/6 mice were sensitized and challenged with ovalbumin (OVA). Blood samples were collected to measure specific immunoglobulins. The mice were divided into six groups that underwent the active cutaneous anaphylaxis procedure. Group 1 (negative control) received 50 μl of phosphate-buffered saline (PBS) subcutaneously, and the other five groups were sensitized with 50 μg of OVA subcutaneously. Group 2 was the positive control, and the others received the anti-PD-L1 antibody or its isotype during sensitization (groups 3 and 4) or during the challenge (groups 5 and 6). All animals that underwent ACA on the ears with OVA and PBS were sacrificed, and the reaction was evaluated by extravasation of Evans blue (measured by spectrophotometry) and histological analysis of the collected fragments. Anti-PD-L1 blockade during the sensitization phase led to a reduction in specific IgE and IgG1 levels, allergic reaction intensity at the ACA site, and mast cell degranulation in the tissue. There was no significant biological effect of anti-PD-L1 administration on the challenge phase. PD-L1 blockade during allergen sensitization inhibited the synthesis of specific IgE and IgG1 and decreased mast cell activation in this murine model of anaphylaxis.

Old Friends with Unexploited Perspectives: Current Advances in Mesenchymal Stem Cell-Based Therapies in Asthma

Mesenchymal stem cells (MSCs) have a great regenerative and immunomodulatory potential that was successfully tested in numerous pre-clinical and clinical studies of various degenerative, hematological and inflammatory disorders. Over the last few decades, substantial immunoregulatory effects of MSC treatment were widely observed in different experimental models of asthma. Therefore, it is tempting to speculate that stem cell-based treatment could become an attractive means to better suppress asthmatic airway inflammation, especially in subjects resistant to currently available anti-inflammatory therapies. In this review, we discuss mechanisms accounting for potent immunosuppressive properties of MSCs and the rationale for their use in asthma. We describe in detail an intriguing interplay between MSCs and other crucial players in the immune system as well as lung microenvironment. Finally, we reveal the potential of MSCs in maintaining airway epithelial integrity and alleviating lung remodeling.

Ubiquitous Overexpression of Chromatin Remodeling Factor SRG3 Exacerbates Atopic Dermatitis in NC/Nga Mice by Enhancing Th2 Immune Responses

The SWItch (SWI)3-related gene (SRG3) product, a SWI/Sucrose Non-Fermenting (SNF) chromatin remodeling subunit, plays a critical role in regulating immune responses. We have previously shown that ubiquitous SRG3 overexpression attenuates the progression of Th1/Th17-mediated experimental autoimmune encephalomyelitis. However, it is unclear whether SRG3 overexpression can affect the pathogenesis of inflammatory skin diseases such as atopic dermatitis (AD), a Th2-type immune disorder. Thus, to elucidate the effects of SRG3 overexpression in AD development, we bred NC/Nga (NC) mice with transgenic mice where SRG3 expression is driven by the β-actin promoter (SRG3^β-actin mice). We found that SRG3^β-actin NC mice exhibit increased AD development (e.g., a higher clinical score, immunoglobulin E (IgE) hyperproduction, and an increased number of infiltrated mast cells and basophils in skin lesions) compared with wild-type NC mice. Moreover, the severity of AD pathogenesis in SRG3^β-actin NC mice correlated with expansion of interleukin 4 (IL4)-producing basophils and mast cells, and M2 macrophages. Furthermore, this accelerated AD development is strongly associated with Treg cell suppression. Collectively, our results have identified that modulation of SRG3 function can be applied as one of the options to control AD pathogenesis.

Immune checkpoint inhibitors-induced eosinophilic pneumonia: A case report

A 78‐year‐old male with renal cell carcinoma was treated with combined immunotherapy of nivolumab and ipilimumab. After four courses of the treatment, a chest computed tomography (CT) revealed newly formed ground‐glass opacities (GGOs) in both the lower lung lobes; drug‐induced pneumonia was speculated. Eosinophil counts were elevated in both peripheral blood and bronchoalveolar lavage fluid. Both the immune checkpoint inhibitors (ICIs) were discontinued, following which the chest CT findings improved. Based on these findings, a diagnosis of ICI‐induced eosinophilic pneumonia was made. Hence, clinicians should be wary of the risk of eosinophilic pneumonia during ICI‐anticancer therapy.

Programmed cell death-1 blockade in kidney carcinoma may induce eosinophilic granulomatosis with polyangiitis: a case report

Background

Immune checkpoint inhibitors have potential applications in treating various cancers but are associated with immune-related adverse events, such as inflammation, in a wide range of organs; however, allergic inflammation caused by these agents has not been extensively studied.

Case presentation

A 65-year-old man was diagnosed with a kidney neuroendocrine carcinoma. Three months after kidney resection surgery, the tumor cells had metastasized to his liver and lymph nodes. Subsequently, the patient started chemotherapy; however, regardless of treatment, the tumor grew, and the patient experienced a series of adverse effects, such as taste disorder, anorexia, and general fatigue. Finally, he was administered a programmed cell death (PD)-1 inhibitor, nivolumab (biweekly, toal 200 mg/body), which was effective against kidney carcinoma. However, the patient had a bronchial asthma attack at 22 cycles of nivolumab treatment and chest computed tomography (CT) revealed an abnormal bilateral shadow after 37 cycles of nivolumab treatment. Bronchoscopy findings revealed eosinophil infiltration in the lungs along with severe alveolar hemorrhage. Paranasal sinus CT scanning indicated sinusitis and nerve conduction analysis indicated a decrease in his right ulnar nerve conduction velocity. Based on these findings, the patient was diagnosed with eosinophilic granulomatosis with polyangiitis; he was treated with prednisolone, which alleviated his bronchial asthma. To restart nivolumab treatment, the dose of prednisolone was gradually tapered, and the patient was administered a monthly dose of mepolizumab and biweekly dose of nivolumab. To date, there have been no bronchial attacks or CT scan abnormalities upon follow up.

Conclusions

We present a rare case in which a patient with cancer was diagnosed with eosinophilic granulomatosis with polyangiitis following treatment with a PD-1 inhibitor. Blockade of PD-1 and the programmed cell death ligand (PD-L) 1/PD-1 and PD-L2/PD-1 signaling cascade may cause allergic inflammation. Further studies are needed to identify the specific mechanisms underlying allergic inflammation after PD-1 blockade.

Eosinophils and T cell surface molecule transcript levels in the blood differentiate eosinophilic esophagitis (EoE) from GERD

We recently rereported that blood mRNA levels of T cells and IgE receptors are the novel non-invasive biomarkers for eosinophilic esophagitis (EoE) with the aim to establish the panel of T cells and IgE receptor as the novel non-invasive biomarkers for EoE. In addition to earlier proposed cell surface molecules, we now added T cell receptor CXCR6 and eosinophils expressed cell surface molecules CD101 and CD274 mRNA levels. The mRNA levels of eosinophils cell surface molecule CD101 and CD274 and T cell receptor CXCR6, Vβ11, CD1d and chemokine CXCL16 levels were examined using the blood of normal, EoE and GERD patients. The analysis showed statistically significant induced mRNA levels of CD274, CD101 and reduced CXCR6 will be an additional molecule with respective 95%, 90% and 90% positive predictive value in between EoE and GERD patients. In brief, these additional data will be critical to establish a complete panel of earlier published TCRδ (95%), Jα18 (83%) and FCεRII (100%) non-invasive biomarker to monitor the EoE severity and treatment effect in EoE patients. In conclusion, we now propose both induced and reduced transcript levels of cell surface molecules of the cell surface molecules along with earlier reported molecules that will be useful for monitoring EoE status before and following treatment. Most importantly, the complete predictive non-invasive biomarker panel will also serve to differentiate EoE from GERD.

A tissue-specific collaborative mixed model for jointly analyzing multiple tissues in transcriptome-wide association studies

Transcriptome-wide association studies (TWASs) integrate expression quantitative trait loci (eQTLs) studies with genome-wide association studies (GWASs) to prioritize candidate target genes for complex traits. Several statistical methods have been recently proposed to improve the performance of TWASs in gene prioritization by integrating the expression regulatory information imputed from multiple tissues, and made significant achievements in improving the ability to detect gene-trait associations. Unfortunately, most existing multi-tissue methods focus on prioritization of candidate genes, and cannot directly infer the specific functional effects of candidate genes across different tissues. Here, we propose a tissue-specific collaborative mixed model (TisCoMM) for TWASs, leveraging the co-regulation of genetic variations across different tissues explicitly via a unified probabilistic model. TisCoMM not only performs hypothesis testing to prioritize gene-trait associations, but also detects the tissue-specific role of candidate target genes in complex traits. To make full use of widely available GWASs summary statistics, we extend TisCoMM to use summary-level data, namely, TisCoMM-S2. Using extensive simulation studies, we show that type I error is controlled at the nominal level, the statistical power of identifying associated genes is greatly improved, and the false-positive rate (FPR) for non-causal tissues is well controlled at decent levels. We further illustrate the benefits of our methods in applications to summary-level GWASs data of 33 complex traits. Notably, apart from better identifying potential trait-associated genes, we can elucidate the tissue-specific role of candidate target genes. The follow-up pathway analysis from tissue-specific genes for asthma shows that the immune system plays an essential function for asthma development in both thyroid and lung tissues.

A narrative review of synergistic drug administration in unresectable locally advanced non-small cell lung cancer: current landscape and future prospects in the era of immunotherapy

Based on the PACIFIC study, the standard care of unresectable locally advanced non-small cell lung cancer (LA-NSCLC) shifted from concurrent chemo-radiotherapy (CCRT) alone to CCRT followed by durvalumab consolidation in 2017. In the era of immunotherapy, two kinds of therapeutic drugs are involved in the management of LA-NSCLC: chemotherapeutics and anti-PD-1/PD-L1 agents. However, the best choices of systematic chemotherapy, immunotherapy, and treatment schedule remain controversial. The immune modulation effects of chemotherapy, as well as the potential immunosuppressive impact of pretreatment medications, should be taken into consideration. Indeed, chemotherapeutics are double-edged swords to immunotherapy, with both stimulatory and suppressive effects on the immune system. Moreover, low-dose chemotherapy is reported to enhance anti-tumor immune responses with reduced toxicities. As for glucocorticoids, there is no consensus about its exact impact on the efficacy of immunotherapy. In addition, the timing of anti-PD-1/PD-L1 agent related to CCRT has three modes: induction, concurrent, and consolidation therapy. Although CCRT followed by durvalumab consolidation is the standard of care, the best sequence of immunotherapy and chemo-radiotherapy is still under debate. Furthermore, the efficacy and toxicity of various PD-1/PD-L1 inhibitors should be compared, especially in the background of CCRT. In this review, we will summarize the detailed knowledge about chemotherapeutics and anti-PD-1/PD-L1 axis agents, and discuss the potential implications in designing novel, effective treatment strategies for LA-NSCLC.

Human Rhinovirus Infection Enhances the Th2 Environment in Allergic and Non-allergic Patients with Chronic Rhinosinusitis

Objectives.

This study was conducted to determine whether patients with allergic rhinitis might be more susceptible to human rhinovirus (HRV) infection and whether the effects of infection on the elicited immune responses are different in allergic and non-allergic patients with chronic rhinosinusitis (CRS).

Methods.

Uncinate process tissues were obtained from 61 CRS patients (of whom 39 had allergies and 22 did not) and were infected with HRV-16 using an air-liquid interface organ culture system. The expression levels of programmed cell death-ligand (PD-L)1, PD-L2, intracellular adhesion molecule 1, interferon-gamma (IFN-γ), interleukin (IL)-4, IL-5, and IL-10 were evaluated in the infected nasal mucosa.

Results.

The HRV infection rates were not significantly different between the allergy (74.4%) and non-allergy (72.7%) groups. In the allergy group, the expression of PD-L1 (P=0.013) and IL-10 (P=0.040) was significantly elevated in the HRV-infected tissues, and there was a strong correlation between PD-L1 and IL-10 (r=0.868, P<0.001). In contrast, infected tissues from the non-allergy group displayed increased levels of IL-4 (P=0.039), IL-5 (P=0.023), and IFN-γ (P=0.031), as well as an increased IL-4/IFN-γ ratio, after HRV infection (P=0.043).

Conclusion.

This study showed that HRV infection rates were similar in the nasal mucosa of patients with CRS regardless of the presence of allergic rhinitis. HRV infection enhanced the Th2 environment by modulating PD-L1 and PD-L2 expression levels in allergic mucosa and by increasing the IL-4/IFN-γ ratio in non-allergic mucosa.

Novel findings in immunopathophysiology of chronic rhinosinusitis and their role in a model of precision medicine

Our understanding of the pathophysiology of chronic rhinosinusitis (CRS) is continuously evolving. The traditional description of CRS in terms of two phenotypes based on the presence or absence of nasal polyps belies the underlying intricate immunopathophysiological processes responsible for this condition. CRS is being increasingly recognized as a disease spectrum encompassing a range of inflammatory states in the sinonasal cavity, with non-type 2 inflammatory disease on one end, type 2 inflammatory, eosinophil-heavy disease on the other and an overlap of both in different proportions in between. Abundance in research on the immune mechanisms of CRS has revealed various new endotypes that hold promise as biomarkers for the development of targeted therapies in severe, uncontrolled CRS. The introduction of precision medicine to manage this chronic, complex condition is a step forward in providing individualized care for all patients with CRS. In this review, the latest research on the pathophysiology of CRS with a focus on potential novel biomarkers and treatment options over the last 2 years are summarized and integrated into a suggested model of precision medicine in CRS.

Allergic disease, corticosteroid use, and risk of Hodgkin lymphoma: A United Kingdom nationwide case-control study

BACKGROUND

Immunodeficiency syndromes (acquired/congenital/iatrogenic) are known to increase Hodgkin lymphoma (HL) risk, but the effects of allergic immune dysregulation and corticosteroids are poorly understood.

OBJECTIVE

We sought to assess the risk of HL associated with allergic disease (asthma, eczema, and allergic rhinitis) and corticosteroid use.

METHODS

We conducted a case-control study using the United Kingdom Clinical Practice Research Datalink (CPRD) linked to hospital data. Multivariable logistic regression investigated associations between allergic diseases and HL after adjusting for established risk factors. Potential confounding or effect modification by steroid treatment were examined.

RESULTS

One thousand two hundred thirty-six patients with HL were matched to 7416 control subjects. Immunosuppression was associated with 6-fold greater odds of HL (adjusted odds ratio [aOR], 6.18; 95% CI, 3.04-12.57), with minimal change after adjusting for steroids. Any prior allergic disease or eczema alone was associated with 1.4-fold increased odds of HL (aOR, 1.41 [95% CI, 1.24-1.60] and 1.41 [95% CI, 1.20-1.65], respectively). These associations decreased but remained significant after adjustment for steroids (aOR, 1.25 [95% CI, 1.09-1.43] and 1.27 [95% CI, 1.08-1.49], respectively). There was no effect modification by steroid use. Previous steroid treatment was associated with 1.4-fold greater HL odds (aOR, 1.38; 95% CI, 1.20-1.59).

CONCLUSIONS

In addition to established risk factors (immunosuppression and infectious mononucleosis), allergic disease and eczema are risk factors for HL. This association is only partially explained by steroids, which are associated with increased HL risk. These findings add to the growing evidence that immune system malfunction after allergic disease or immunosuppression is central to HL development.

Landscape of Immune-Related Pneumonitis in Cancer Patients with Asthma Being Treated with Immune Checkpoint Blockade

INTRODUCTION

Predicting the factors that increase the risk of immune-related pneumonitis, a potentially life-threatening complication of treatment with immune checkpoint inhibitors for cancer, is a clinical challenge. Baseline clinical factors such as asthma may portend the development of pneumonitis due to pre-existing airway inflammation prior to immunotherapy.

OBJECTIVE

The purpose of the study was to investigate whether a prior diagnosis of asthma is associated with an increased risk of immune-related pneumonitis in patients undergoing cancer immunotherapy.

METHODS

Patients at the Moores Cancer Center at UC San Diego Health undergoing immunotherapy were identified on an IRB-approved protocol. Clinical charts were reviewed for asthma documented in the medical records and CT scans were reviewed during and after treatment. Pneumonitis was defined as the onset of new pulmonary symptoms with characteristic imaging findings during or after a patient's first course of immunotherapy that could not be readily explained as infection or a progression of malignancy. It was graded according to the Common Terminology Criteria for Adverse Events.

RESULTS

A total of 187 patients were included. A diagnosis of asthma was found in the records of 26 cases (13.9%). Pneumonitis was found in 10 cases (5.35%); 50% were grade 2 and 50% were grade 3-4. Two of the grade 3-4 cases (40%) occurred in patients with non-small-cell lung cancer. Three patients with asthma developed pneumonitis (11.5% of patients with asthma), all grade 3-4. Only 28.6% of the non-asthma-pneumonitis cases were grade 3-4. All (100%) of the asthma-pneumonitis patients were former smokers, while 71.4% of the non-asthma-pneumonitis patients were former smokers.

CONCLUSION

A history of asthma may be associated with a higher grade of pneumonitis if it develops, and a history of smoking may augment this relationship.

Effect of PD-1 inhibitor on exhaled nitric oxide and pulmonary function in non-small cell lung cancer patients with and without COPD

Background

Nivolumab, a programmed death 1 (PD-1) immune checkpoint inhibitor, has been shown to improve survival in non-small cell lung cancer (NSCLC). The possible involvement of PD-1 axis in the pathogenesis of inflammatory lung disease, such as chronic obstructive pulmonary disease (COPD) has also been reported. However, effects of PD-1 blockade on the respiratory system remain unknown.

Objectives

This prospective study aimed to investigate whether inhibition of the PD-1 axis altered lung inflammation and pulmonary function in NSCLC patients with and without COPD.

Method

This was a prospective multi-center study. Measurements of fractioned exhaled nitric oxide (FeNO) and pulmonary function were performed before and after 4 cycles of nivolumab therapy.

Results

A total of 137 patients with NSCLC were initially enrolled, and subsequently 95 patients (41 COPD and 54 non-COPD) receiving 4 cycles of nivolumab administration were included. After anti-PD-1 therapy, FeNO levels were significantly elevated together with increase in peripheral eosinophils. Interestingly, significant FeNO elevation was only found in COPD patients without increased peripheral eosinophils, but this was not the case in non-COPD patients. Additionally, COPD patients exhibited significant increases in FVC and FEV₁ but no changes in dyspnea scales, and acute exacerbation did not occur during the therapy.

Conclusion

Our observations suggest that anti-PD-1 therapy changed FeNO levels and pulmonary function in NSCLC patients. This therapy does not worsen COPD in terms of symptoms, pulmonary function, or acute exacerbation.

B7-H3 participates in human salivary gland epithelial cells apoptosis through NF-κB pathway in primary Sjögren's syndrome

Background

Primary Sjögren’s syndrome (pSS) is an autoimmune disorder mainly characterized by exocrine gland injury. Costimulatory molecules play an important role in immune-regulatory networks. Although B7 family costimulatory molecules were previously discovered in human salivary gland epithelial (HSGE) cells in pSS, the effects of the B7 family member B7-H3 (CD276) have not been well elucidated. Thus, this study aimed to investigate the role and mechanism of B7-H3 in HSGE cells in pSS.

Methods

The expression of B7-H3, B7-H1, PD-1 in serum, saliva and salivary gland were examined by immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA). Immunofluorescence was used to test the expression and distribution of B7-H3, AQP5 and CK-8 in salivary gland tissues. Flow cytometry, Cell Counting Kit 8 (CCK-8) and western blot (WB) were performed to research the apoptotic, proliferative and inflammatory effects of B7-H3 in primary HSGE cells and HSGE cell lines.

Results

Our results showed that the expression of PD-1, B7-H1 and B7-H3 in peripheral blood, and salivary glands in pSS patients was higher than that in healthy controls, which was positive correlation with the grade of the salivary glands. The expression of B7-H3 in saliva was higher in pSS patients than that in healthy controls, which was detected with the most significant difference of them. The expression of B7-H3 in primary HSGE cells of pSS patients was significantly higher than healthy controls. B7-H3 increased activity of NF-κB pathway and promoted inflammation of HSGE cells, decreasing the expression of AQP5. Furthermore, B7-H3 overexpression inhibited proliferation and induced apoptosis in HSGE cell lines.

Conclusion

B7-H3 could promote inflammation and induce apoptosis of HSGE cells by activating NF-κB pathway, which might be a promising therapeutic target for pSS.

Increased intratumoral mast cells foster immune suppression and gastric cancer progression through TNF-α-PD-L1 pathway

Background

Mast cells are prominent components of solid tumors and exhibit distinct phenotypes in different tumor microenvironments. However, the nature, regulation, function, and clinical relevance of mast cells in human gastric cancer (GC) are presently unknown.

Methods

Flow cytometry analyses were performed to examine level and phenotype of mast cells in samples from 114 patients with GC. Multivariate analysis of prognostic factors for overall survival was performed using the Cox proportional hazards model. Kaplan-Meier plots for patient survival were performed using the log-rank test. Mast cells, T cells and tumor cells were isolated or generated, stimulated and/or cultured for in vitro and in vivo function assays.

Results

Patients with GC showed a significantly higher mast cell infiltration in tumors. Mast cell levels increased with tumor progression and independently predicted reduced overall survival. These tumor-infiltrating mast cells accumulated in tumors by CXCL12-CXCR4 chemotaxis. Intratumoral mast cells expressed higher immunosuppressive molecule programmed death-ligand 1 (PD-L1), and mast cells induced by tumors strongly express PD-L1 proteins in both time-dependent and dose-dependent manners. Significant correlations were found between the levels of PD-L1⁺ mast cells and pro-inflammatory cytokine TNF-α in GC tumors, and tumor-derived TNF-α activated NF-κB signaling pathway to induce mast cell expression of PD-L1. The tumor-infiltrating and tumor-conditioned mast cells effectively suppressed normal T-cell immunity through PD-L1 in vitro, and tumor-conditioned mast cells contributed to the suppression of T-cell immunity and the growth of human GC tumors in vivo; the effect could be reversed by blocking PD-L1 on these mast cells.

Conclusion

Thus, our results illuminate novel immunosuppressive and protumorigenic roles of mast cells in GC, and also present a novel mechanism in which PD-L1 expressing mast cells link the proinflammatory response to immune tolerance in the GC tumor milieu.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0530-3) contains supplementary material, which is available to authorized users.

Allergic bronchopulmonary aspergillosis presumably unmasked by PD-1 inhibition

Programmed cell death-1 (PD-1) inhibitors stimulate immune recognition of tumour cells in cancer patients, but have significant autoimmune side effects including pneumonitis. We report the case of a patient with asthma and mild eosinophilia who developed unusual pulmonary side effect of bronchiectasis, severe eosinophilia (absolute eosinophil count: 3200 c/mm³) and elevated IgE levels (7050 IU/mL; normal: <164 IU/mL) 4 months into therapy with the PD-1 inhibitor pembrolizumab. Aspergillus fumigatus IgG was elevated at 15.60 U/mL (normal: <12.01 U/mL). He responded to therapy with corticosteroids and voriconazole and was able to resume pembrolizumab thereafter with good clinical response.

Prognostic values of increased B7 family proteins in haploidentical hematopoietic stem cell transplantation patients with aGVHD

It has been reported that B7H1 and B7H3 play a role in graft-versus-host disease (GVHD), the major cause of treatment-related mortality (TRM) in haploidentical hematopoietic stem cell transplantation (haplo-HSCT) patients; however, the prognostic value of these factors has not been defined. We retrospectively collected 64 haplo-HSCT patients in our hospital from 2013 to 2014, as well as 38 HLA-matched-HSCT patients during the same period as the control group. We analyzed B7H1, B7H3, PD1, soluble CD25, ST2 and TNFR1 at 0 day, + 7 days, + 14 days and + 28 days after HSCT. The + 7 days/+ 14 days B7H1/B7H3 and + 28 days ST2 serum levels were higher in patients with aGVHD who underwent haplo-HSCT. Moreover, + 7 days B7H1/B7H3 serum levels were predictive of grade III-IV aGVHD (B7H1: AUC = 0.830, P < 0.001; B7H3: AUC = 0.775, P = 0.001). Haplo-HSCT patients with higher + 7 days B7H1/B7H3 or + 28 days ST2 serum levels had poor GVHD-related mortality (GRM) (B7H1: P < 0.001; B7H3: P = 0.002; ST2: P = 0.047). Multivariate analysis revealed that the + 7 days B7H1 serum level (P = 0.041), as well as viral infection (P = 0.015) and donor age (P = 0.012), could independently predict GRM. Collectively, we found that + 7 days B7H1/B7H3 serum levels can predict grade III-IV aGVHD, while only the + 7 days B7H1 serum level, together with viral infection and donor age, could independently predict GRM in patients with haplo-HSCT.

IRAK-M Associates with Susceptibility to Adult-Onset Asthma and Promotes Chronic Airway Inflammation

IL-1R-associated kinase (IRAK)-M regulates lung immunity during asthmatic airway inflammation. However, the regulatory effect of IRAK-M differs when airway inflammation persists. A positive association between IRAK-M polymorphisms with childhood asthma has been reported. In this study, we investigated the role of IRAK-M in the susceptibility to adult-onset asthma and in chronic airway inflammation using an animal model. Through genetic analysis of IRAK-M polymorphisms in a cohort of adult-onset asthma patients of Chinese Han ethnicity, we identified two IRAK-M single nucleotide polymorphisms, rs1624395 and rs1370128, genetically associated with adult-onset asthma. Functionally, the top-associated rs1624395, with an enhanced affinity to the transcription factor c-Jun, was associated with a higher expression of IRAK-M mRNA in blood monocytes. In contrast to the protective effect of IRAK-M in acute asthmatic inflammation, we found a provoking impact of IRAK-M on chronic asthmatic inflammation. Following chronic OVA stimulation, IRAK-M knockout (KO) mice presented with significantly less inflammatory cells, a lower Th2 cytokine level, a higher IFN-γ concentration, and increased percentage of Th1 cells in the lung tissue than wild type mice. Moreover, lung dendritic cells (DC) from OVA-treated IRAK-M KO mice expressed a higher percentage of costimulatory molecules PD-L1 and PD-L2. Mechanistically, in vitro TLR ligation led to a greater IFN-γ production by IRAK-M KO DCs than wild type DCs. These findings demonstrated a distinctive role of IRAK-M in maintaining chronic Th2 airway inflammation via inhibiting the DC-mediated Th1 activation and indicated a complex role for IRAK-M in the initiation and progression of experimental allergic asthma.

PD-L2 expression is correlated with the molecular and clinical features of glioma, and acts as an unfavorable prognostic factor

Background: Gliomas are aggressive tumors with various molecular and clinical characteristics and exhibit strongly resistance to radio-chemotherapy. Programmed cell death 1 ligand 2 (PD-L2) is a cell surface protein, which was reported in many cancers, modulating cancer-associated immune responses, while the role of PD-L2 in gliomas remained unclear. Herein, we aimed to investigate the biological behaviors and clinical prognostic values of PD-L2 in gliomas.

Methods: Totally, we enrolled RNA sequencing data of 325 glioma samples from Chinese Glioma Genome Atlas (CGGA) as training cohort and RNA expression data of 1032 samples from The Cancer Genome Atlas (TCGA) dataset as validation cohort in this research. Then, the clinical and molecular characteristics, and the prognostic value of PD-L2 were analyzed.

Results: We found that PD-L2 expression level was significantly upregulated in higher grade glioma and IDH wild-type glioma. Receiver Operating Characteristic (ROC) analysis revealed that PD-L2 was a potential indicator of mesenchymal subtype. PD-L2 exhibited tight relationship with immune response and immune-modulating process in glioma. Moreover, PD-L2 expression level could predict unfavorable prognoses of patients independent of age, grade, IDH status and 1p/19q status.

Conclusions: Our study revealed that PD-L2 was closely related with inflammation and immune response. Patients with lower PD-L2 expression level tended to experience improved survival. Targeting PD-L2 may become a valuable approach for the treatment of gliomas in clinical practice.

PD-1 has a unique capacity to inhibit allergen-specific human CD4+ T cell responses

T lymphocytes have a crucial role in initiating and promoting type I allergies. Their responses are tightly regulated by numerous activating and inhibitory signals provided by APCs. Here we have addressed the role of the major coinhibitory receptors PD-1, CTLA-4, BTLA and LAG-3 in allergen-specific CD4⁺ T cell responses. PBMCs of healthy individuals and 41 patients allergic to house dust mites, birch, grass or mugwort pollen were stimulated with allergenic extracts and expression of coinhibitory receptors on responding CD4⁺ T cells was assessed. Blocking antibodies to PD-1, CTLA-4, BTLA and LAG-3 were used to evaluate the role of coinhibitory pathways. Allergen-specific CD4⁺ T cells showed strong upregulation of PD-1, LAG-3 and CTLA-4 upon stimulation, whereas BTLA was downregulated. Blockade of PD-1 strongly enhanced proliferation and cytokine production (IL-10; T_H1 cytokines IFN-γ, TNF-α; T_H2 cytokines IL-5, IL-13) of allergen-specific CD4⁺ T cells derived from allergic as well as non-allergic individuals. BTLA blockade enhanced proliferation but not cytokine production in response to house dust mite extract. Blocking LAG-3 was ineffective and surprisingly, we observed reduced proliferation and cytokine production in presence of a CTLA-4 antibody. Our results point to a unique potency of PD-1 pathways to dampen allergen-specific human T cells.

Expression of Programmed Death-Ligand 1 by Human Colonic CD90+ Stromal Cells Differs Between Ulcerative Colitis and Crohn's Disease and Determines Their Capacity to Suppress Th1 Cells

Background and Aims

The role of programmed cell death protein 1 (PD-1) and its ligands in the dysregulation of T helper immune responses observed in the inflammatory bowel disease (IBD) is unclear. Recently, a novel concept emerged that CD90⁺ colonic (myo)fibroblasts (CMFs), also known as stromal cells, act as immunosuppressors, and are among the key regulators of acute and chronic inflammation. The objective of this study was to determine if the level of the PD-1 ligands is changed in the IBD inflamed colonic mucosa and to test the hypothesis that changes in IBD-CMF-mediated PD-1 ligand-linked immunosuppression is a mechanism promoting the dysregulation of Th1 cell responses.

Methods

Tissues and cells derived from Crohn's disease (CD), ulcerative colitis (UC), and healthy individuals (N) were studied in situ, ex vivo, and in culture.

Results

A significant increase in programmed death-ligand 1 (PD-L1) was observed in the inflamed UC colonic mucosa when compared to the non-inflamed matched tissue samples, CD, and healthy controls. UC-CMFs were among the major populations in the colonic mucosa contributing to the enhanced PD-L1 expression. In contrast, PD-L1 expression was decreased in CD-CMFs. When compared to CD-CMFs and N-CMFs, UC-CMFs demonstrated stronger suppression of IL-2, Th1 transcriptional factor Tbet, and IFN-γ expression by CD3/CD28-activated CD4⁺ T cells, and this process was PD-L1 dependent. Similar observations were made when differentiated Th1 cells were cocultured with UC-CMFs. In contrast, CD-CMFs showed reduced capacity to suppress Th1 cell activity and addition of recombinant PD-L1 Fc to CD-CMF:T cell cocultures partially restored the suppression of the Th1 type responses.

Conclusion

We present evidence showing that increased PD-L1 expression suppresses Th1 cell activity in UC. In contrast, loss of PD-L1 expression observed in CD contributes to the persistence of the Th1 inflammatory milieu in CD. Our data suggest that dysregulation of the Th1 responses in the inflamed colonic mucosa of IBD patients is promoted by the alterations in PD-L1 expression in the mucosal mesenchymal stromal cell compartment.

New insight into cancer immunotherapy

A key point for maintenance of the immune system homeostasis is the balance between the capacity to recognize and fight exogenous molecules and the capacity to avoid auto reactivity. The disruption of this balance induces the progression of several immune diseases such as autoimmune diseases, allergies, infections or cancer. A promising therapeutic approach to treat these diseases is immunotherapy. In cancer, both active and passive immunotherapies have been tested with promising results, such as the blocking of immunological checkpoints like CTLA-4 and PD-1. These treatments, in the market since a few years ago, aim to redirect the patient's immunological response by inhibiting the induction of regulatory T cells, both in the priming and effector phases. This strategy sheds light on the immunological mechanisms that control the regulatory response mediated by T cells and opens new lines of research into other immunological diseases such as allergy, in which the induction of a regulatory response is necessary to avoid allergic progression and which is the main objective of allergen-specific immunotherapies available today.

Differential regulation of PD-1 and its ligands in allergic asthma

BACKGROUND

Targeting PD-1/PD-1 ligand signalling is an established treatment option for cancer. The role of these molecules in allergic asthma has been investigated in several mouse studies yielding conflicting results. However, human studies investigating the expression and regulation of PD-1 and its ligands in allergic inflammation are lacking.

OBJECTIVE

To analyse the expression and regulation of PD-1 and its ligands in human allergic asthma.

METHODS

The well-established human asthma model of segmental allergen challenge (SAC) was used to analyse the regulation of PD-1 and its ligands PD-L1 and PD-L2 on T lymphocytes and dendritic cells by flow cytometry. The impact of immunoglobulin E (IgE)-mediated signalling on PD-L1 expression was analysed on isolated plasmacytoid dendritic cells (pDCs).

RESULTS

PD-1 expression by blood CD4⁺ T cells was negatively associated with total and specific (against the allergen used for provocation) IgE serum concentrations. Twenty-four hours after SAC, a small decrease in endobronchial PD-1⁺ CD4⁺ T cells was accompanied by an increase in PD-L1 expression on endobronchial myeloid dendritic cells (mDCs) and pDCs. The PD-L1 up-regulation on pDCs was not induced by IgE-mediated mechanisms. In contrast, PD-L2 was only detected on endobronchial mDCs and was significantly down-regulated 24 hours after SAC.

CONCLUSION AND CLINICAL RELEVANCE

This study shows, for the first time, an association of a low PD-1 expression by circulating CD4⁺ T cells with high total and specific (against the allergen used for provocation) IgE concentrations in allergic asthma. In addition, we demonstrate a differential regulation of PD-1 ligands on endobronchial DCs after allergen challenge which may favour Th2 inflammation. Therefore, modulating PD-1 ligand-mediated pathways might be a promising target in allergic asthma.

Blomia tropicalis allergen 5 (Blo t 5) T-cell epitopes and their ability to suppress the allergic immune response

Blomia tropicalis is the major asthma allergen in the tropics comparable to Dermatophagoides pteronyssinus. However, little is known about the B. tropicalis epitopes recognized by T cells. Our aim was to identify the T-cell epitopes in the major B. tropicalis allergen, Blo t 5, and investigate the potential of the corresponding peptides to inhibit the allergic inflammatory lung response. C57BL/6 mice were immunized with plasmid DNA encoding Blo t 5 and T-cell epitopes identified using the interferon-γ ELISPOT assay with 15-mer overlapping peptides. C57BL/6 mice were sensitized with bone-marrow-derived dendritic cells (BMDC) pulsed with Blo t 5 allergen followed by intranasal Blo t 5 challenge. Two H-2^b restricted epitopes (Bt5_76-90 and Bt5_106-115 ) were recognized by CD4 T cells specific for Blo t 5, but no CD8 epitopes were identified. In mice sensitized with Blo t 5-pulsed BMDC and challenged with intranasal Blo t 5 Bt5_76-90 and Bt5_106-115 , peptide-specific CD4 T cells were found to secrete the T helper type 2 cytokines interleukin-5 and interleukin-13. Intradermal administration of synthetic peptides encoding the identified T-cell epitopes suppressed allergic airway inflammation to further allergen challenges. Hence, we have identified novel CD4 T-cell epitopes specific for Blo t 5 and demonstrated that these peptides could be employed therapeutically to suppress the T-cell response in a murine model of allergic airway inflammation.

Programmed cell death-1 expression correlates with disease severity and IL-5 in chronic rhinosinusitis with nasal polyps

BACKGROUND

Programmed cell death-1 (PD-1) is a negative regulator of T-cell responses. Expression of PD-1 and its ligands PD-L1 and PD-L2 in chronic rhinosinusitis with nasal polyps (CRSwNP) is poorly studied.

METHODS

Expression of PD-1, PD-L1, PD-L2, TGF-β, IL-5, and IL-10 mRNA was measured by real-time quantitative PCR on tissue homogenates of patients with CRSwNP (n = 21) and healthy controls (n = 21) and on primary epithelial cells. Disease severity was scored using the Lund-Mackay scores of maxillofacial computed tomography (CT) scans. Expression of PD-1 and PD-L1/L2 was evaluated at the cellular and tissue levels (n = 6) by flow cytometry and immunohistochemistry.

RESULTS

Programmed cell death-1 mRNA expression was increased in tissue homogenates from patients with CRSwNP compared with controls, irrespective of the atopy status. Importantly, expression of PD-1 correlated with the total CT scan scores (r = 0.5, P = 0.02). Additionally, a significant association was found between PD-1 mRNA and expression of IL-5 mRNA in control nasal tissue (r = 0.95, P < 0.0001) and in CRSwNP (r = 0.63, P = 0.002). PD-1 was expressed on different subsets of T cells and CD11b^- dendritic cells. Both PD-1 and its ligands were expressed on primary epithelial cells from control nasal tissue and nasal polyp tissue.

CONCLUSIONS

Higher PD-1 expression was found in CRSwNP than in nasal tissue from controls. This was associated with disease severity and tissue IL-5 expression but unrelated to the patients' atopy status.

Dendritic cells conditioned by activin A-induced regulatory T cells exhibit enhanced tolerogenic properties and protect against experimental asthma

BACKGROUND

Previously, we demonstrated that regulatory T (Treg) cells induced by the cytokine activin-A suppress T_H2-mediated allergic responses and linked airway disease. Still, the effects of activin-A-induced regulatory T (Act-A-iTreg) cells on the regulation of dendritic cell (DC)-driven allergic inflammation remain elusive.

OBJECTIVE

Here we investigated whether Act-A-iTreg cells can modulate DC responses and endow them with enhanced tolerogenic functions.

METHODS

Using adoptive cell transfer studies in mouse models of allergic airway disease, we examined the effects of Act-A-iTreg cells on DC phenotype, maturation status, and T_H2 cell priming potential. Genome-wide gene expression profiling characterized the transcriptional networks induced in tolerogenic DCs by Act-A-iTreg cells. The ability of DCs conditioned by Act-A-iTreg cells (Act-A-iTreg cell-modified DCs) to protect against experimental asthma, and the mechanisms involved were also explored.

RESULTS

Act-A-iTreg cell-modified DCs exhibited a significantly impaired capacity to uptake allergen and stimulate naive and T_H2 effector responses on allergen stimulation in vivo accompanied by markedly attenuated inflammatory cytokine release in response to LPS. Gene-profiling studies revealed that Act-A-iTreg cells dampened crucial T_H2-skewing transcriptional networks in DCs. Administration of Act-A-iTreg cell-modified DCs ameliorated cardinal asthma manifestations in preventive and therapeutic protocols through generation of strongly suppressive forkhead box P3⁺ Treg cells. Finally, programed death protein 1/programmed death ligand 1 signaling pathways were essential in potentiating the generation of DCs with tolerogenic properties by Act-A-iTreg cells.

CONCLUSION

Our studies reveal that Act-A-iTreg cells instruct the generation of a highly effective immunoregulatory circuit encompassing tolerogenic DCs and forkhead box P3⁺ Treg cells that could be targeted for the design of novel immunotherapies for allergic disorders.

Pulmonary Delivery of Virosome-Bound Antigen Enhances Antigen-Specific CD4+ T Cell Proliferation Compared to Liposome-Bound or Soluble Antigen

Pulmonary administration of biomimetic nanoparticles loaded with antigen may represent an effective strategy to directly modulate adaptive immune responses in the respiratory tract. Depending on the design, virosomes may not only serve as biomimetic antigen carriers but are also endowed with intrinsic immune-stimulatory properties. We designed fluorescently labeled influenza-derived virosomes and liposome controls coupled to the model antigen ovalbumin to investigate uptake, phenotype changes, and antigen processing by antigen-presenting cells exposed to such particles in different respiratory tract compartments. Both virosomes and liposomes were captured by pulmonary macrophages and dendritic cells alike and induced activation in particle-bearing cells by upregulation of costimulatory markers such as CD40, CD80, CD86, PD-L1, PD-L2, and ICOS-L. Though antigen processing and accumulation of both coupled and soluble antigen was similar between virosomes and liposomes, only ovalbumin-coupled virosomes generated a strong antigen-specific CD4⁺ T cell proliferation. Pulmonary administrated antigen-coupled virosomes therefore effectively induced adaptive immune responses and may be utilized in novel preventive or therapeutic approaches in the respiratory tract.

Schistosome-induced pulmonary B cells inhibit allergic airway inflammation and display a reduced Th2-driving function

Chronic schistosome infections protect against allergic airway inflammation (AAI) via the induction of IL-10-producing splenic regulatory B (Breg) cells. Previous experiments have demonstrated that schistosome-induced pulmonary B cells can also reduce AAI, but act independently of IL-10. We have now further characterized the phenotype and inhibitory activity of these protective pulmonary B cells. We excluded a role for regulatory T (Treg) cell induction as putative AAI-protective mechanisms. Schistosome-induced B cells showed increased CD86 expression and reduced cytokine expression in response to Toll-like receptor (TLR) ligands compared with control B cells. To investigate the consequences for T cell activation we cultured ovalbumin (OVA)-pulsed, schistosome-induced B cells with OVA-specific transgenic T cells and observed less Th2 cytokine expression and T cell proliferation compared with control conditions. This suppressive effect was preserved even under optimal T cell stimulation by anti-CD3/28. Blocking of the inhibitory cytokines IL-10 or TGF-β only marginally restored Th2 cytokine induction. These data suggest that schistosome-induced pulmonary B cells are impaired in their capacity to produce cytokines to TLR ligands and to induce Th2 cytokine responses independent of their antigen-presenting function. These findings underline the presence of distinct B cell subsets with different stimulatory or inhibitory properties even if induced by the same type of helminth.

Inverse correlation of soluble programmed cell death-1 ligand-1 (sPD-L1) with eosinophil count and clinical severity in allergic rhinitis patients

BACKGROUND

T-cell response outcome is determined by co-stimulatory/inhibitory signals. Programmed cell death-1 ligand-1 (PD-L1) is a member of these co-signaling molecules with known soluble form in human serum. Soluble PD-L1 (sPD-L1) is also recognized in patients with some types of malignancy or autoimmune disorders, though there are few studies on sPD-L1 roles in allergic diseases. The purpose of this survey was to evaluate the association between sPD-L1 levels with eosinophil count as well as disease severity in allergic rhinitis (AR) patients.

METHODS

90 patients with AR were selected. Disease severity was determined by a modified Allergic Rhinitis and its Impact on Asthma (ARIA) classification as mild, moderate and severe. Whole blood samples were collected. Then eosinophil count and serum sPD-L1 were detected by a hematologic analyzer and a commercial ELISA kit.

RESULTS

13 (14.44%), 31 (34.44%), and 46 (51.12%) of patients had mild, moderate and severe disease, respectively. The mean levels of sPD-L1 and eosinophil count were ascertained 18.38 ± 14.42 ng/ml and 422.43 ± 262.26 cell/μl. A significant inverse correlation was determined between sPD-L1 levels and eosinophil count (r = -0.364, P < 0.001). Moreover, we detected a significant negative association between sPD-L1 levels and disease severity (r = -0.384, P < 0.001).

CONCLUSIONS

It is deduced that sPD-L1 can be used as a helpful marker to determine the severity of AR. Furthermore, this study indicated that sPD-L1 may have an inhibitory role in AR development, and its modulation may be considered as a useful accessory therapeutic approach for reduction of AR progression.