Early antiretroviral therapy-treated perinatally HIV-infected seronegative children demonstrate distinct long-term persistence of HIV-specific T-cell and B-cell memory

OBJECTIVE

To investigate long-term persistence of HIV-specific lymphocyte immunity in perinatally HIV-infected children treated within the first year of life.

DESIGN

Twenty perinatally HIV-infected children who received ART therapy within the first year of life (early treated) and with stable viral control (>5 years) were grouped according to their serological response to HIV.

METHODS

Western blot analysis and ELISA defined 14 HIV-seropositive and six seronegative patients. Frequencies of gp140-specific T-cell and B-cell, and T-cell cytokine production were quantified by flow cytometry in both seronegatives and seropositives. Transcriptional signatures in purified gp140-specific B-cell subsets, in response to in-vitro stimulation with HIV peptides was evaluated by multiplex RT-PCR.

RESULTS

Gp140-specific T cells and B cells persist at similar levels in both groups. A higher production of IL-21 in gp140-specific T cells was found in seropositives vs. seronegatives (P = 0.003). Gene expression in switched IgM-IgD- gp140-specific memory B cells after stimulation with HIV peptides in vitro demonstrated a differential expression of genes involved in signal transduction and activation after BCR/TLR triggering and B-cell activation. Genes relating to antibody production (PRDM1) and T-B cognate stimulation (CXCR4, IL21R) were differentially induced after in-vitro stimulation in seronegatives vs. seropositives suggesting a truncated process of B-cell maturation.

CONCLUSION

HIV-specific memory B and T cells persist in early treated regardless their serological status. Seronegatives and seropositives are distinguished by gp140-specific T-cell function and by distinct transcriptional signatures of gp140-specific B cells after in-vitro stimulation, presumably because of a different antigen exposure. Such qualitative insights may inform future immunotherapeutic interventions.

Cutaneous Adverse Events of Anti-PD-1 Therapy and BRAF Inhibitors

OPINION STATEMENT

The treatment of advanced melanoma has undergone a dramatic transformation over the last decade with the advent of targeted and immunomodulatory therapies. This transition from cytotoxic chemotherapy has yielded improvements in both survival and quality of life; yet despite their therapeutic advantages, these treatments have been associated with a diverse range of cutaneous adverse events (AEs). These range from relatively benign eczematous conditions to more severe inflammatory and bullous disorders, and can include induction of second malignancies. AEs can result in serious morbidity and risk of mortality if not recognised and managed early. As a consequence of their novelty, and rapid uptake, these agents have been subject to intense scrutiny and there is a general understanding that cutaneous AEs should be anticipated in treatment plans. Dermatologists should be integrated into management teams to assist in the development of treatment protocols for anticipated common AEs and to provide expert management of more severe, rare or unusual AEs. Our experience has shown a reduction in treatment interruptions, more rapid recognition of unusual AEs and improved management pathways for patients suffering cutaneous AEs.

B Cells Improve Overall Survival in HPV-Associated Squamous Cell Carcinomas and Are Activated by Radiation and PD-1 Blockade

PURPOSE

To characterize the role of B cells on human papilloma virus (HPV)-associated cancer patient outcomes and determine the effects of radiation and PD-1 blockade on B-cell populations.

EXPERIMENTAL DESIGN

Tumor RNA-sequencing data from over 800 patients with head and neck squamous cell carcinoma (HNSCC) and cervical cancer, including a prospective validation cohort, was analyzed to study the impact of B-cell gene expression on overall survival (OS). A novel murine model of HPV⁺ HNSCC was used to study the effects of PD-1 blockade and radiotherapy on B-cell activation, differentiation, and clonality including analysis by single-cell RNA-sequencing and B-cell receptor (BCR)-sequencing. Human protein microarray was then used to quantify B-cell-mediated IgG and IgM antibodies to over 16,000 proteins in the serum of patients treated on a clinical trial with PD-1 blockade.

RESULTS

RNA-sequencing identified CD19 and IGJ as novel B-cell prognostic biomarkers for 3-year OS (HR, 0.545; P < 0.001). PD-1 blockade and radiotherapy enhance development of memory B cells, plasma cells, and antigen-specific B cells. BCR-sequencing found that radiotherapy enhances B-cell clonality, decreases CDR3 length, and induces B-cell somatic hypermutation. Single-cell RNA-sequencing identified dramatic increases in B-cell germinal center formation after PD-1 blockade and radiotherapy. Human proteome array revealed enhanced IgG and IgM antibody responses in patients who derived clinical benefit but not those with progressive disease after treatment with PD-1 blockade.

CONCLUSIONS

These findings establish a key role for B cells in patient outcomes and responses to PD-1 blockade in HPV-associated squamous cell carcinomas and demonstrate the need for additional diagnostics and therapeutics targeting B cells.

Immune-related adverse events of checkpoint inhibitors: Insights into immunological dysregulation

Immune checkpoint inhibitors (ICIs) targeting against programmed cell death-1(PD-1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) have shown efficacy in cancer treatment. However, a spectrum of immune-related adverse events (irAEs) have raised concerns about their clinical application. IrAEs are distinct from traditional chemo- and radiotherapy-induced toxicities, as they are related in particular to the dysregulation of immune system and autoimmunity. The underlying pathogenesis of irAEs remains elusive. Understanding of the potential underlying mechanism is of great importance for the management of irAEs and the development of new ICIs with insignificant irAEs. In this review, we summarize the current evidence to provide insights into the biological basis of irAEs and provide a potential explanation for their pathogenesis, with focus on the relationship between checkpoint molecules and immune cell regulation.

The role of B lymphocytes in the immuno-biology of non-small-cell lung cancer

Tumour-infiltrating immune cells have been widely implicated to play a significant role in carcinogenesis, through both pro- or anti-tumour effects. The multi-faceted effects of lung cancer associated T lymphocytes have been extensively studied, and yet, the role of B lymphocytes remains an area less studied. In this review, we will describe the current understanding of the role of tumour-infiltrating B lymphocytes in NSCLC, discuss their prognostic significance, their functionality within the tumour microenvironment and ultimately how we might harness B-cell biology to develop B-cell therapeutic strategies in cancer.

B Cell Compartmentalization in Blood and Cerebrospinal Fluid of HIV-Infected Ugandans with Cryptococcal Meningitis

Activated B cells modulate infection by differentiating into pathogen-specific antibody-producing effector plasmablasts/plasma cells, memory cells, and immune regulatory B cells. In this context, the B cell phenotypes that infiltrate the central nervous system during human immunodeficiency virus (HIV) and cryptococcal meningitis coinfection are ill defined. We characterized clinical parameters, mortality, and B cell phenotypes in blood and cerebrospinal fluid (CSF) by flow cytometry in HIV-infected adults with cryptococcal (n = 31) and noncryptococcal (n = 12) meningitis and in heathy control subjects with neither infection (n = 10). Activation of circulating B cells (CD21low) was significantly higher in the blood of subjects with HIV infection than in that of healthy controls and greater yet in matched CSF B cells (P < 0.001). Among B cell subsets, elevated frequencies of memory and plasmablasts/plasma cells most clearly distinguished the CSF from blood compartments. With cryptococcal meningitis, lower frequencies of expression of the regulatory protein programmed death-1 (PD-1) on plasmablasts/plasma cells in blood (median, 7%) at presentation were associated with significantly decreased 28-day survival (29% [4/14 subjects]), whereas higher PD-1 expression (median, 46%) characterized subjects with higher survival (88% [14/16 subjects]). With HIV infection, B cell differentiation and regulatory markers are discrete elements of the circulating and CSF compartments with clinical implications for cryptococcal disease outcome, potentially due to their effects on the fungus and other local immune cells.

B cell checkpoints in autoimmune rheumatic diseases

B cells have important functions in the pathogenesis of autoimmune diseases, including autoimmune rheumatic diseases. In addition to producing autoantibodies, B cells contribute to autoimmunity by serving as professional antigen-presenting cells (APCs), producing cytokines, and through additional mechanisms. B cell activation and effector functions are regulated by immune checkpoints, including both activating and inhibitory checkpoint receptors that contribute to the regulation of B cell tolerance, activation, antigen presentation, T cell help, class switching, antibody production and cytokine production. The various activating checkpoint receptors include B cell activating receptors that engage with cognate receptors on T cells or other cells, as well as Toll-like receptors that can provide dual stimulation to B cells via co-engagement with the B cell receptor. Furthermore, various inhibitory checkpoint receptors, including B cell inhibitory receptors, have important functions in regulating B cell development, activation and effector functions. Therapeutically targeting B cell checkpoints represents a promising strategy for the treatment of a variety of autoimmune rheumatic diseases.

The Adaptive and Innate Immune Cell Landscape of Uterine Leiomyosarcomas

Reactivation of the anti-tumor response has shown substantial progress in aggressive tumors such as melanoma and lung cancer. Data on less common histotypes are scanty. Immune checkpoint inhibitor therapy has been applied to few cases of uterine leiomyosarcomas, of which the immune cell composition was not examined in detail. We analyzed the inflammatory infiltrate of 21 such cases in high-dimensional, single cell phenotyping on routinely processed tissue. T-lymphoid cells displayed a composite phenotype common to all tumors, suggestive of antigen-exposure, acute and chronic exhaustion. To the contrary, myelomonocytic cells had case-specific individual combinations of phenotypes and subsets. We identified five distinct monocyte-macrophage cell types, some not described before, bearing immunosuppressive molecules (TIM3, B7H3, VISTA, PD1, PDL1). Detailed in situ analysis of routinely processed tissue yields comprehensive information about the immune status of sarcomas. The method employed provides equivalent information to extractive single-cell technology, with spatial contexture and a modest investment.

Relationship between Programmed Cell Death Protein Ligand 1 Expression and Immune-related Adverse Events in Non-small-cell Lung Cancer Patients Treated with Pembrolizumab

Introduction:

Immune checkpoint inhibitors (ICIs) can lead to immune-related adverse events (irAEs). A correlation between the development of irAEs and efficacy has been suggested; however, it is unclear whether there is a relationship between programmed death ligand 1 (PD-L1) expression and the development of these events.

Methods:

We performed a retrospective study of advanced or metastatic non-small cell lung cancer (NSCLC) patients who were treated with pembrolizumab monotherapy at our institution between May 2015 and April 2018 (n = 44). Patients were categorized into two groups, specifically those with irAEs (irAE group) or without (non-irAE group), and we evaluated the objective response rate (ORR), disease control rate (DCR), and progression-free survival (PFS). Predictors of irAEs were examined by multivariate analysis.

Results:

irAEs of any grade occurred in 31 (70.5%) patients. The median PFS was 10.9 months in the irAE group versus 3.7 months in the non-irAE group (P < 0.001). ORR and DCR were also higher in the irAE group than in the non-irAE group. Furthermore, high PD-L1 expression (≥50%) was a predictive factor of irAE based on logistic regression (P = 0.004).

Conclusions:

In patients with advanced NSCLC treated with pembrolizumab monotherapy, ORR, DCR, and PFS were significantly better in the irAE group than in the non-irAE group. High PD-L1 expression, at the time of pretreatment, was identified as an independent predictor of irAE development. We believe that more careful management of irAEs for individuals with high PD-L1 expression is needed to improve clinical benefits. Further, PD-L1 expression might be useful for ICI risk management.

The pathological role of B cells in systemic lupus erythematosus: From basic research to clinical

Systemic lupus erythematosus (SLE) is an autoimmune disease that often occurs in females of child-bearing age. It involves multiple systems and severely threatens human life. One of the typical characteristics of SLE is the formation of immune complexes with autoantibodies produced by B cells that target various autoantigens, thus indicating the pivotal role of B cells in the pathogenesis of SLE. Increasing evidence has shown abnormal expression of B cells in the peripheral blood of SLE patients. Moreover, numerous studies have shown that B cells in SLE patients are abnormally activated, as well as aberrantly differentiated, and are involved in the inflammatory cytokine milieu, abnormal transcription factor activity, and signalling pathways. Several biological therapies targeting B cells, such as anti-CD20 antibodies, have been intensively studied in preclinical and clinical trials. However, the results have not met expectations. Therefore, new therapies targeting B cells are in great need. This review will summarize the latest progress in basic research on B cells to better understand the pathogenesis of SLE and will discuss the outcomes of B-cell-targeting treatments that provide potential therapeutic targets and strategies for SLE. Studies have clarified high levels of IL-21 in serum from SLE patients and animal models. IL-21 promotes B cell differentiation, which results in antibodies accumulation leads to SLE. Therefore, further studies on IL-21 will give new perspectives on SLE treatments. In addition, the application of drugs targeting plasma cell depletion in SLE patients may also achieve satisfied results in treatment.

Chimeric antigen receptor T cells in solid tumors: a war against the tumor microenvironment

Chimeric antigen receptor (CAR) T cell is a novel approach, which utilizes anti-tumor immunity for cancer treatment. As compared to the traditional cell-mediated immunity, CAR-T possesses the improved specificity of tumor antigens and independent cytotoxicity from major histocompatibility complex molecules through a monoclonal antibody in addition to the T-cell receptor. CAR-T cell has proven its effectiveness, primarily in hematological malignancies, specifically where the CD 19 CAR-T cells were used to treat B-cell acute lymphoblastic leukemia and B-cell lymphomas. Nevertheless, there is little progress in the treatment of solid tumors despite the fact that many CAR agents have been created to target tumor antigens such as CEA, EGFR/EGFRvIII, GD2, HER2, MSLN, MUC1, and other antigens. The main obstruction against the progress of research in solid tumors is the tumor microenvironment, in which several elements, such as poor locating ability, immunosuppressive cells, cytokines, chemokines, immunosuppressive checkpoints, inhibitory metabolic factors, tumor antigen loss, and antigen heterogeneity, could affect the potency of CAR-T cells. To overcome these hurdles, researchers have reconstructed the CAR-T cells in various ways. The purpose of this review is to summarize the current research in this field, analyze the mechanisms of the major barriers mentioned above, outline the main solutions, and discuss the outlook of this novel immunotherapeutic modality.

Profiling Preexisting Antibodies in Patients Treated With Anti-PD-1 Therapy for Advanced Non-Small Cell Lung Cancer

Importance

Administration of anti-programmed cell death protein 1 (anti-PD-1) is now standard therapy in advanced non-small cell lung cancer (NSCLC). However, immune checkpoint inhibitors, including anti-PD-1, have not been assessed in patients with subclinical disease with advanced NSCLC, and no useful clinical biomarkers have been associated with immune-related adverse events (irAEs) among these patients treated with anti-PD-1.

Objective

To assess the safety and efficacy of anti-PD-1 treatment in patients with subclinical disease with advanced NSCLC and with or without preexisting autoimmune markers, including rheumatoid factor, antinuclear antibody, antithyroglobulin, and antithyroid peroxidase; and to assess potential clinical biomarkers that may be meaningfully and conveniently associated with clinical benefit or with irAEs following anti-PD-1 treatment.

Design, Setting, and Participants

This medical records analysis retrospectively evaluated 137 patients who received nivolumab or pembrolizumab monotherapy at Sendai Kousei Hospital in Japan between January 2016 and January 2018. Treatment efficacy and irAEs were evaluated along with candidate factors that may be associated with irAEs.

Exposures

Absence or presence of specific autoimmune markers and antibodies before treatment.

Main Outcomes and Measures

Preexisting antibodies and autoimmune markers, progression-free survival (PFS), and irAEs.

Results

Of 137 patients with advanced NSCLC, 105 were men, the median age was 68 (range, 36-88) years, 99 underwent nivolumab monotherapy, 38 underwent pembrolizumab monotherapy, and 134 had an Eastern Cooperative Oncology Group performance status of 0 or 1. The median PFS was 6.5 (95% CI, 4.4-12.9) months among patients with examined preexisting antibodies and 3.5 (95% CI, 2.4-4.1) months among patients without, suggesting significantly better prognosis in the former. The hazard ratio for disease progression or death in the presence of the examined preexisting antibodies was 0.53 (95% CI, 0.36-0.79; P = .002). The PFS was significantly longer among patients with any preexisting antibodies than among those without. The examined preexisting antibodies (48 patients [73%]) and rheumatoid factor (26 patients [39%]) were more common among patients who developed irAEs. Multivariate analysis indicated that the presence of the examined preexisting antibodies was independently associated with irAEs (odds ratio, 3.25; 95% CI, 1.59-6.65; P = .001). Skin reactions were more frequent among patients with preexisting rheumatoid factor (47% vs 24%, P = .02), whereas thyroid dysfunction was more frequent among patients with preexisting antithyroid antibodies (20% vs 1%, P < .001).

Conclusions and Relevance

The presence of the examined preexisting antibodies was associated with clinical benefit and with the development of irAEs in patients with NSCLC treated with nivolumab or pembrolizumab. Thus, the presence of these autoimmune markers may help determine the risk-benefit ratio for individual patients with NSCLC, maximizing therapeutic benefits while minimizing irAEs.

Adverse effects of immune-checkpoint inhibitors: epidemiology, management and surveillance

Immune-checkpoint inhibitors (ICIs), including anti-cytotoxic T lymphocyte antigen 4 (CTLA-4), anti-programmed cell death 1 (PD-1) and anti-programmed cell death 1 ligand 1 (PD-L1) antibodies, are arguably the most important development in cancer therapy over the past decade. The indications for these agents continue to expand across malignancies and disease settings, thus reshaping many of the previous standard-of-care approaches and bringing new hope to patients. One of the costs of these advances is the emergence of a new spectrum of immune-related adverse events (irAEs), which are often distinctly different from the classical chemotherapy-related toxicities. Owing to the growing use of ICIs in oncology, clinicians will increasingly be confronted with common but also rare irAEs; hence, awareness needs to be raised regarding the clinical presentation, diagnosis and management of these toxicities. In this Review, we provide an overview of the various types of irAEs that have emerged to date. We discuss the epidemiology of these events and their kinetics, risk factors, subtypes and pathophysiology, as well as new insights regarding screening and surveillance strategies. We also highlight the most important aspects of the management of irAEs.

Association Between Skin Reaction and Clinical Benefit in Patients Treated with Anti-Programmed Cell Death 1 Monotherapy for Advanced Non-Small Cell Lung Cancer

BACKGROUND

Anti-programmed cell death 1 antibody is a standard therapy for advanced non-small cell lung cancer (NSCLC). However, immune-related adverse events (irAEs), such as skin reactions, are frequently observed. Although skin reactions are associated with clinical efficacy in melanoma, this association in advanced NSCLC and predictors of irAEs remain unclear. Accordingly, this study identified potential correlations of skin reactions with clinical efficacy and clinical predictors of development of skin reactions.

SUBJECTS, MATERIALS, AND METHODS

We retrospectively surveyed patients with advanced NSCLC who received nivolumab or pembrolizumab monotherapy at Sendai Kousei Hospital (n = 155) during January 2016 to April 2018. Treatment efficacy was evaluated in patients with and without skin reactions, and associated predictive markers were determined. A 6-week landmark analysis was conducted to assess the clinical benefit of early skin reactions.

RESULTS

Skin reactions were observed in 51 patients with a median time to onset of 6.4 weeks. The overall response rate (ORR) was significantly higher in patients with skin reactions (57% vs. 19%, p < .001). Median progression-free survival (PFS) durations of 12.9 and 3.5 months and overall survival durations of not reached and 11.4 months were observed in patients with and without skin reactions, respectively. In the 6-week landmark analysis, the ORR was significantly higher in patients with skin reactions, and skin reactions were significantly associated with increased PFS. A multivariate analysis identified pre-existing rheumatoid factor (RF) as an independent predictor of skin reactions.

CONCLUSION

Skin reactions appeared beneficial in patients treated with nivolumab/pembrolizumab for advanced NSCLC and could be predicted by pre-existing RF. Further large-scale validations studies are warranted.

IMPLICATIONS FOR PRACTICE

This single-institutional medical record review that included 155 patients with advanced non-small cell lung cancer who were treated with nivolumab or pembrolizumab monotherapy revealed that overall response rate and progression-free survival were significantly better in patients with skin reactions. Pre-existing rheumatoid factor was an independent predictor of skin reactions.

Immune Checkpoint Inhibitors: Basics and Challenges

Cancer is one of the most deadly diseases in the modern world. The last decade has witnessed dramatic advances in cancer treatment through immunotherapy. One extremely promising means to achieve anti-cancer immunity is to block the immune checkpoint pathways - mechanisms adopted by cancer cells to disguise themselves as regular components of the human body. Many review articles have described a variety of agents that are currently under extensive clinical evaluation. However, while checkpoint blockade is universally effective against a broad spectrum of cancer types and is mostly unrestricted by the mutation status of certain genes, only a minority of patients achieve a complete response. In this review, we summarize the basic principles of immune checkpoint inhibitors in both antibody and smallmolecule forms and also discuss potential mechanisms of resistance, which may shed light on further investigation to achieve higher clinical efficacy for these inhibitors.

Classical Hodgkin's Lymphoma in the Era of Immune Checkpoint Inhibition

The ligation of programmed cell death 1 (PD-1) with programmed cell death ligand PD-L activates the immune checkpoint leading to T-cell dysfunction, exhaustion, and tolerance, especially in Hodgkin lymphoma (HL) where the PD-L/ Janus kinase (Jak) signaling was frequently found altered. Anti-PD-1 or anti-PD-L1 monoclonal antibodies can reverse this immune checkpoint, releasing the brake on T-cell responses. The characterization of the mechanisms regulating both the expression of PD-1 and PD-L and their function(s) in HL is ongoing. We provide in this review the recent findings focused on this aim with special attention on the major research topics, such as adverse events and resistance to PD-1–PD-L1 inhibitor treatment, together with a part about angiogenesis, extracellular vesicles, and microbiome in HL pathogenesis.

B-cell frequencies and immunoregulatory phenotypes in myeloproliferative neoplasms: Influence of ruxolitinib, interferon-α2, or combination treatment

OBJECTIVE

Given a proposed role for PD-L1⁺ and IL-10-producing B-cell subsets in promoting certain cancers, we sought to characterize the frequency and phenotype of B cells in patients with chronic myeloproliferative neoplasms (MPNs) and the influence of ruxolitinib and interferon-α2 therapy.

METHODS

We analyzed B-cell frequencies and phenotype in patients with MPNs (n = 107), before and during treatment with ruxolitinib (n = 29), interferon-α2 (n = 21), or the two drugs in combination (COMBI; n = 42) and healthy donors (HDs; n = 52) using flow cytometry.

RESULTS

Myelofibrosis patients had lower lymphocyte counts and proportions of B cells than patients with essential thrombocythemia or polycythemia vera and HDs. The B-cell count correlated inversely with JAK2-V617F allele burden and spleen size and increased after ruxolitinib or COMBI treatment. The proportions of PD-L1⁺ B cells and PD-1⁺ B cells were significantly higher in patients with myelofibrosis or polycythemia vera than in HDs and decreased during ruxolitinib and COMBI treatment. The proportions of TNF-α⁺ and IL-6⁺ B cells were elevated in myelofibrosis patients. The proportion of IL-6⁺ B cells decreased, and the proportion of IL-10⁺ B cells increased during ruxolitinib treatment.

CONCLUSION

B-cell frequency and phenotype were altered in MPN patients. Ruxolitinib therapy had marked effects on both frequency and phenotype.

Heterogeneity of Memory Marginal Zone B Cells

The marginal zone (MZ) is largely composed of a unique subpopulation of B cells, the so-called MZ-B cells. At a molecular level, memory B cells are characterized by the presence of somatically mutated IGV genes. The earliest studies in the rat have documented the presence of hapten-specific MZ-B cells after immunization in the MZ. This work later received experimental support demonstrating that the IGHV-Cµ transcripts expressed by phenotypically defined splenic MZ-B cells (defined as CD90^negIgM^highIgD^low B cells) can carry somatic hypermutation. However, only a minor fraction (< 10%-20%) of these MZ-B cells is mutated and is considered to represent memory B cells. Memory B cells can either be class-switched (IgG, IgA, IgE), or non-class-switched (IgM) B cells. B cells in the MZ are a heterogeneous population of cells and both naïve MZ-B cells; class switched and unswitched memory MZ-B cells are present at this unique site in the spleen. Naïve MZ-B cells carry unmutated Ig genes, produce low-affinity IgM molecules and constitute a first line of defense against invading pathogens. Memory MZ-B cells express high-affinity Ig molecules, directed to (microbial) antigens that have been encountered. In this review, we report on the memory compartment of splenic MZ-B cells in the rat to provide insights into the origin and function of these memory MZ-B cells.

Immune inhibitory proteins and their pathogenic and therapeutic implications in autoimmunity and autoimmune hepatitis

Key inhibitory proteins can blunt immune responses to self-antigens, and deficiencies in this repertoire may promote autoimmunity. The goals of this review are to describe the key immune inhibitory proteins, indicate their possible impact on the development of autoimmune disease, especially autoimmune hepatitis, and encourage studies to clarify their pathogenic role and candidacy as therapeutic targets. English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed. Cytotoxic T lymphocyte antigen-4 impairs ligation of CD28 to B7 ligands on antigen presenting cells and inhibits the adaptive immune response by increasing anti-inflammatory cytokines, generating regulatory T cells, and reducing T cell activation and proliferation. Programed cell death antigen-1 inhibits T cell selection, activation, and proliferation by binding with two ligands at different phases and locations of the immune response. A soluble alternatively spliced variant of this protein can dampen the inhibitory signal. Autoimmune hepatitis has been associated with polymorphisms of the cytotoxic T lymphocyte antigen-4 gene, reduced hepatic expression of a ligand of programed cell death antigen-1, an interfering soluble variant of this key inhibitory protein, and antibodies against it. Findings have been associated with laboratory indices of liver injury and suboptimal treatment response. Abatacept, belatacept, CD28 blockade, and induction of T cell exhaustion are management considerations that require scrutiny. In conclusion, deficiencies in key immune inhibitory proteins may promote the occurrence of autoimmune diseases, such as autoimmune hepatitis, and emerging interventions may overcome these deficiencies. Investigations should define the nature, impact and management of these inhibitory disturbances in autoimmune hepatitis.

Aristolochic Acid and Immunotherapy for Urothelial Carcinoma: Directions for unmet Needs

Urothelial carcinoma of the bladder (UCB) and upper tracts (UTUC) used to share management with similar principles. However, their genetic and epigenetic differences along with different responses to immunotherapy were recently identified, which are reminiscent of their distinct etiologies. Different from the variety of environmental factors relating to UCB, UTUC is best known for its close relationship with exposure to aristolochic acid (AA). AA is believed to cause its carcinogenicity through forming DNA adducts of deoxyadenosine-aristolactam, as well as A:T → T:A transversions in the TP53 tumor suppressor gene. Since recent findings suggested that cancers with higher somatic mutations are associated with better treatment responses upon immune checkpoint blockade, UTUC and AA-related biomarkers reasonably serve as good candidates, as well as a potential prognostic predictor for the flourishing immunotherapy. This review covers the current state of the literature on the clinical response of UTUC and UCB receiving immunotherapy and points out directions for refinement regarding patient selection.

AIHA and Pancytopenia as Complications of Pembrolizumab Therapy for Metastatic Melanoma: A Case Report

Immunotherapy has been an emerging treatment for metastatic melanoma and several other malignancies since 2015. Hematological immune-mediated adverse effects from immunotherapy are rarely reported but they can cause serious harm to patients. Antibodies such as ipilimumab, nivolumab and pembrolizumab target different immune checkpoints to promote T cell anti-tumour response. In particular, pembrolizumab is an antibody that inhibits programmed cell death receptor 1 (PD-1) to upregulate tumour suppression. In this report, we present a case of pembrolizumab-induced autoimmune hemolytic anemia and pancytopenia in a patient who was receiving pembrolizumab treatment for metastatic melanoma. This patient has a history of chronic lymphocytic leukemia and was diagnosed with metastatic melanoma in 2017. He developed symptomatic AIHA and pancytopenia after receiving 8 cycles of pembrolizumab in 2018. Pembrolizumab treatment was discontinued and he was treated with blood transfusion and prednisone. After 5 months of tapering prednisone treatment, his anemia and pancytopenia have improved toward successful recovery. Cancer patients already face an increased risk of immunosuppression with conventional chemotherapy. This case report also summarized all reported cases of PD-1 inhibitor hematological adverse effects in the treatment of oncological diseases. These incidents reflect the risk of immune-mediated hematologic adverse effects, which should be considered in all patients using immunotherapy.

High tumoral PD-L1 expression and low PD-1+ or CD8+ tumor-infiltrating lymphocytes are predictive of a poor prognosis in primary diffuse large B-cell lymphoma of the central nervous system

We investigated the clinicopathological role of the PD-1/PD-L1 pathway in primary diffuse large B-cell lymphoma of the central nervous system (PCNS-DLBCL) arising in the immune-privileged site. PD-L1 immunostaining of ≥30% of tumor cells was defined as tPD-L1+, and PD-L1 immunostaining of ≥30% of total cellularity, including tumor and non-tumoral cells, as tmPD-L1+ . PD-1⁺ and CD8⁺ tumor-infiltrating lymphocytes (TILs) were enumerated. Thirty-five cases (35.7%) were tPD-L1+ and 47 cases (48%) were tmPD-L1+ . The number of TILs was greater in tmPD-L1+ cases than in tmPD-L1- cases (CD8⁺, P= .050; PD-1⁺, P= .019). tPD-L1+ and tmPD-L1+ cases tended to have a poor performance status. In contrast, the numbers of CD8⁺ and PD-1⁺ TILs tended to be higher in patients with a good performance status and MYC/BCL2 negativity. Patients with tPD-L1+ had a worse overall survival (P= .026), and those with increased CD8⁺ or PD-1⁺ TILs tended to have a better overall survival (P= .081 and 0.044, respectively). Tumoral PD-L1 expression and the number of PD-1⁺ TILs were independent prognostic factors. tPD-L1+ patients with a small number of CD8⁺ or PD-1⁺ TILs had the worst prognosis, and tPD-L1- patients with a large number of CD8⁺ or PD-1⁺ TILs had the best prognosis. In validation group, increased CD8⁺ or PD-1⁺ TILs were significantly associated with a prolonged survival, but PD-L1 had no prognostic significance. In conclusion, PD-L1 is frequently expressed in tumor cells and the immune microenvironment of PCNS-DLBCL and is correlated with increased TILs. PD-L1 and CD8⁺ and PD-1⁺ TILs have potential as prognostic biomarkers and therapeutic targets in PCNS-DLBCL.

Prognostic Impact of Adenosine Receptor 2 (A2aR) and Programmed Cell Death Ligand 1 (PD-L1) Expression in Colorectal Cancer

Background

Programmed cell death ligand 1 (PD-L1) is a key inhibitor to the immune response by binding to the specific receptor PD-1. Adenosine receptor 2 (A2aR) can play an immunosuppressive role in tumor microenvironment by binding to its ligand adenosine (ADO). However, the expression of these two markers has been rarely studied in colorectal cancer simultaneously.

Materials and Methods

We, respectively, collected tumor and adjacent nontumor tissue specimens of 204 patients with colorectal cancer. The expressions of PD-L1 and A2aR were detected by immunohistochemistry. The association among their expressions with clinicopathological characteristics and prognostic parameters were analyzed as well.

Results

The expressions of PD-L1 and A2aR in tumor tissues were both higher than those in matched adjacent nontumor tissues. PD-L1 expression was significantly correlated with lymph node metastasis and tumor TNM stage. A2aR expression was significantly correlated with tumor size, depth of tumor invasion, and TNM stage. Univariate analysis showed that the high expressions of PD-L1 and A2aR were inversely correlated with the overall survival, respectively. Multivariate analysis further confirmed that both of them were independent prognostic markers for patients.

Conclusion

The results of this study suggested that the high expressions of PD-L1 and A2aR were associated with a poor prognosis of colorectal cancer. Coinhibition of these two proteins may be a new breakthrough in the treatment of this disease.

Prognostic value of B cells in cutaneous melanoma

Background

Measures of the adaptive immune response have prognostic and predictive associations in melanoma and other cancer types. Specifically, intratumoral T cell density and function have considerable prognostic and predictive value in skin cutaneous melanoma (SKCM). Less is known about the significance of tumor-infiltrating B cells in SKCM. Our goal was to understand the prognostic and predictive value of B cell phenotypic subsets in SKCM using RNA sequencing.

Methods

We used our previously published algorithm, V’DJer, to assemble B cell receptor (BCR) repertoires and estimate diversity from short-read RNA sequencing (RNA-seq). We applied machine learning-based cellular phenotype classifiers to measure relative similarity of bulk tumor sample gene expression profiles and different B cell phenotypes. We assessed these aspects of B cell biology in 473 SKCM from the Cancer Genome Atlas Project (TCGA) as well as in RNA-seq data corresponding to tumor samples procured from patients who received CTLA-4 and PD-1 inhibitors for metastatic SKCM.

Results

We found that the BCR repertoire was associated with different clinical factors, such as tumor tissue site and sex. However, increased clonality of the BCR repertoire was favorably prognostic in SKCM and was prognostic even after first conditioning on various clinical factors. Mutation burden was not correlated with any BCR measurement, and no specific mutation had an altered BCR repertoire. Lack of an assembled BCR in pre-treatment tumor tissues was associated with a lack of anti-tumor response to a CTLA-4 inhibitor in metastatic SKCM.

Conclusions

These findings suggest an important prognostic and predictive role for B cell characteristics in SKCM. This has implications for melanoma immunobiology and potential development of immunogenomics features to predict survival and response to immunotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13073-019-0647-5) contains supplementary material, which is available to authorized users.

Anti-programmed cell death-1 therapy-associated bullous disorders: a systematic review of the literature

Bullous disorders are rare adverse events associated with anti-programmed cell death-1 (anti-PD1) therapy. This paper presents two new cases of bullous disorders under anti-PD1 therapy and systematically reviewed the literature to foster a better understanding of the presentation and pathogenesis of bullous disorders under anti-PD1. A systematic review of the literature was completed using MEDLINE, Embase, PubMed and LILACS databases. We identified 29 cases of bullous disorders under anti-PD1 therapy, including our two new cases. This includes 18 cases of bullous pemphigoid (BP), five cases of toxic epidermal necrolysis (TEN)/Stevens-Johnson syndrome (SJS) spectrum, one case of erythema multiforme (EM), four cases of bullous lichenoid reactions and one case of vesiculobullous eczema. In BP, blistering occurred by a median of 23 weeks after anti-PD1 therapy initiation and is often preceded by a prodrome, which lasts for a median of 9.5 weeks. Limbs and trunk were the most frequently involved body sites. Most cases (76%) achieved remission. In TEN/SJS/EM, blistering was usually preceded by a prodrome of interface dermatitis that lasted for a median of 1.5 weeks. Most cases (80%) died from either TEN/SJS or disease progression. Bullous disorders under anti-PD1 may be classified clinically as BP, SJS/TEN/EM, bullous lichenoid reactions and vesiculobullous eczema and histologically by intraepidermal splitting and subepidermal splitting. BP is usually preceded by a pruritic eruption and has a relatively good prognosis. SJS/TEN is usually preceded by a maculopapular eruption and has a very poor prognosis.

The B-side of Cancer Immunity: The Underrated Tune

Tumor-infiltrating lymphocytes are known to be critical in controlling tumor progression. While the role of T lymphocytes has been extensively studied, the function of B cells in this context is still ill-defined. In this review, we propose to explore the role of B cells in tumor immunity. First of all we define their dual role in promoting and inhibiting cancer progression depending on their phenotype. To continue, we describe the influence of different tumor microenvironment factors such as hypoxia on B cells functions and differentiation. Finally, the role of B cells in response to therapy and as potential target is examined. In accordance with the importance of B cells in immuno-oncology, we conclude that more studies are required to throw light on the precise role of B cells in the tumor microenvironment in order to have a better understanding of their functions, and to design new strategies that efficiently target these cells by immunotherapy.

Treg-mediated acquired resistance to immune checkpoint inhibitors

T Regulatory cells (Tregs) act as a double-edged sword by regulating immune homeostasis (protective role) and inhibiting immune responses in different disease settings (pathological role). They contribute to cancer development and progression by suppressing T effector cell (Teff) functions. Decreased ratios of intratumoral CD8⁺ T cells to Tregs have been associated with poor prognosis in most cancer types. Targeting immune checkpoints (ICs), such as cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death-1 (PD-1), by immune checkpoint inhibitors (ICIs) in cancer patients has been beneficial in inducing anti-tumor immune responses and improving clinical outcomes. However, response rates remain relatively low, ranging from 15 to 40% depending on cancer type. Additionally, a significant proportion of patients who initially demonstrates a clinical response can acquire resistance overtime. This acquired resistance could occur due to the emergence of compensatory mechanisms within the tumor microenvironment (TME) to evade the anti-tumor effects of ICIs. In this review, we describe the immunosuppressive role of Tregs in the TME, the effects of currently approved ICIs on Treg phenotype and function, and the mechanisms of acquired resistance to ICIs mediated by Tregs within the TME, such as the over-expression of ICs, the up-regulation of immunosuppressive molecules, and apoptotic Treg-induced immunosuppression. We also describe potential therapeutic strategies to target Tregs in combination with ICIs aiming to overcome such resistance and improve clinical outcomes. Elucidating the Treg-mediated acquired resistance mechanisms should benefit the designing of well-targeted therapeutic strategies to overcome resistance and maximize the therapeutic efficacy in cancer patients.

Translation of cancer immunotherapy from the bench to the bedside

The tremendous success of immune checkpoint blockades has revolutionized cancer management. Our increased understanding of the cell types that compose the tumor microenvironment (TME), including those of the innate and adaptive immune system, has helped to shape additional immune modulatory strategies in cancer care. Pre-clinical and clinical investigations targeting novel checkpoint interactions and key pathways that regulate cancer immunity continue to increase rapidly. Various combinatorial drug regimens are being tested in attempt to achieve durable response and survival rates of patients with cancer. This review provides an overview of specific components of the TME, an introduction to novel immune checkpoints, followed by a survey of present day and future combination immune modulatory therapies. The idea that the immune system can recognize and destroy tumor cells was first described in the cancer immunosurveillance hypothesis of Burnet and Thomas. However, early experimental evidence failed to support the concept. It was not until the late 1990s when seminal papers clearly showed the existence of cancer immunosurveillance, leading to the cancer immunoediting hypothesis. In this century, progress in the understanding of negative regulators of the immune response led to the discovery that inhibition of these regulators in patients with cancer could lead to dramatic and durable remissions. Drs. Tasuku Honjo and James P. Allison were awarded the Nobel Prize in 2018 for their pioneering work in this field. We now see rapid advances in cancer immunology and emerging effective therapies revolutionizing cancer care across tumor types in the clinic, while pre-clinical research is moving from a focus on the malignant cells themselves to dissect the highly heterogenic and complex multi-cellular tumor microenvironment (TME).

Incidence of thyroid dysfunctions during treatment with nivolumab for non-small cell lung cancer: Retrospective study of 105 patients

INTRODUCTION

Immunotherapy is a standard not only in second line but also in first line treatment in patients with non-small cell lung cancer (NSCLC) and other tumors. Thyroid dysfunctions are the most common endocrine toxicities.

OBJECTIVE

To determine the incidence of thyroid dysfunctions during treatment with a PD-1 monoclonal antibody (nivolumab) in patients with NSCLC.

METHODS

Retrospective study of patients treated with nivolumab for NSCLC between May 2015 and December 2016; euthyroidism within the 3 months preceding immunotherapy; monitoring of thyroid function tests until stopping nivolumab, death or February 2017. Patients treated with levothyroxine, amiodarone or another immunotherapy were excluded.

RESULTS

Among 183 patients treated, 105 fullfilled the inclusion criteria (72 males, median age: 61 years [range: 41-80]). Fifteen patients (14.3%) experienced a thyroid dysfunction; among them, compared to the "control" group (n=90), we found more females (53.3% vs. 27.8%; P=0.07), and younger patients (median age: 56 years vs. 62 years; P=0.02). Thirteen patients had thyrotoxicosis (median onset: 8 weeks), and then hypothyroidism was observed in 5 patients. Isolated hypothyroidism was rare (n=2) and late (median: 30 weeks). Three patients had anti-TPO antibodies. Three patients discontinued immunotherapy transiently due to thyroid dysfunctions. After a median follow-up of 9 months [95% CI, 7.5-10.3], one patient (6.7%) in the "thyroid dysfunctions" group and 30 patients (33.3%) in the "control" group died, with a trend toward a higher overall survival in the "thyroid dysfunctions" group (HR: 0.16 [95% CI, 0.02-1.15]; P=0.07).

CONCLUSION

Thyroid dysfunctions (isolated thyrotoxicosis, biphasic thyroiditis and hypothyroidism) were common, and required patients with NSCLC to be screened during nivolumab therapy.

Analysis of the dysregulation between regulatory B and T cells (Breg and Treg) in human immunodeficiency virus (HIV)-infected patients

This study examines the relationship between regulatory B (Breg) and T (Treg) compartments, which play crucial roles in the maintenance of immune homeostasis in the context of HIV. Using flow cytometry, the phenotypes of different Breg and Treg subsets from HIV-infected and healthy individuals were analyzed, along with the suppressive capacity of Breg. Peripheral blood samples of thirteen HIV+ treatment-naïve individuals, fourteen treated-HIV+ individuals with undetectable viral load and twelve healthy individuals were analyzed. The absolute counts of Breg and Treg subsets were decreased in HIV+ treatment-naïve individuals in comparison to treated-HIV+ and healthy individuals. Interestingly, correlations between Breg subsets (CD24hiCD27+ and PD-L1+ B cells) and IL-10-producing Breg observed in healthy individuals were lost in HIV+ treatment-naïve individuals. However, a correlation between frequencies of CD24hiCD38hi or TIM-1+-Breg subsets and Treg was observed in HIV+ treatment-naïve individuals and not in healthy individuals. Therefore, we hypothesized that various Breg subsets might have different functions during B and T-cell homeostasis during HIV-1 infection. In parallel, stimulated Breg from HIV-infected treatment-naïve individuals presented a decreased ability to suppress CD4+ T-cell proliferation in comparison to the stimulated Breg from treated-HIV+ or healthy individuals. We demonstrate a dysregulation between Breg and Treg subsets in HIV-infected individuals, which might participate in the hyper-activation and exhaustion of the immune system that occurs in such patients.

Tumor-Specific Delivery of Immune Checkpoint Inhibitors by Engineered AAV Vectors

Immune checkpoint inhibitors (ICIs) can block distinct receptors on T cells or tumor cells thus preventing T cell inactivation and tumor immune escape. While the clinical response to treatment with ICIs in cancer patients is impressive, this therapy is often associated with a number of immune-related adverse events. There is therefore a need to explore innovative strategies of tumor-specific delivery of ICIs. Delivery of therapeutic proteins on a genetic level can be accomplished with viral vectors including those derived from adeno-associated virus (AAV). Here, we assessed the tumor-targeted Her2-AAV, a receptor-targeted AAV vector binding to the tumor antigen Her2/neu for cell entry, as vehicle for ICI gene delivery. Initially, we packaged the coding sequence of a scFv-Fc fusion protein directed against mouse programmed cell death protein-1 (PD-1) into Her2-AAV. Upon transduction of Her2/neu⁺ RENCA cells, AAV-encoded αPD-1 was readily detectable in the cell culture supernatant and revealed specific binding to its target antigen. In vivo, in BALB/c mice bearing subcutaneous RENCA-Her2/neu tumors, Her2-AAV mediated specific gene delivery into tumor tissue upon intravenous administration as verified by luciferase gene transfer and in vivo imaging thus demonstrating unimpaired tumor-targeting by Her2-AAV vectors in immunocompetent animals. When delivering the αPD-1 gene, levels of ICI were similar in tumor tissue for Her2-AAV and AAV2 but substantially reduced in liver for Her2-AAV. When combined with chemotherapy a tendency for reduced progression of tumor growth was documented for Her2-AAV treated mice. To get closer to the clinical situation, AAV constructs that deliver the complete coding sequence of the therapeutic antibody nivolumab which is directed against human PD-1 were generated next. The AAV-Nivolumab constructs were expressed and released from transduced MDA-MB-453 cells in vitro and from RENCA-Her2/neu cells upon intratumoral as well as intravenous administration in vivo. Antibody processing and expression levels were further improved through optimization of construct design. In conclusion, we provide proof-of-principle for redirecting the biodistribution of ICIs from liver and serum to tumor tissue by the use of engineered AAV vectors. This strategy can be easily combined with other types of immunotherapeutic concepts.

Landscape of infiltrating B cells and their clinical significance in human hepatocellular carcinoma

As a major cellular component in tumor microenvironment, the distribution, frequency, and prognostic significance of infiltrating B cell subsets in hepatocellular carcinoma (HCC) remain controversial. Using tyramide signal amplification (TSA) based fluorescent multiplexed immunohistochemistry in situ, we evaluated the distribution and frequency of B cell subsets in two independent HCC cohorts (n = 619). The results were further confirmed by flow cytometry. Correlations of B cell subsets with clinicopathologic features and patient prognosis were analyzed. Five B cell subsets were defined by multiplexed immunohistochemistry and each subset was clearly separated by t-SNE dimension reduction analysis. Notably, the densities of all B cell subsets were significantly decreased in the tumor. The frequency of plasma cells within B cells was most abundant in the tumor. In training cohort (n = 258), high densities of tumor-infiltrating CD20⁺ B cells, naive B cells, IgM⁺ memory B cells, CD27^- isotype-switched memory B cells, and plasma cells were associated with superior survival. Multivariate analysis further identified CD20⁺ B cells, naive B cells, and CD27^- isotype-switched memory B cells as independent prognosticators for survival. Unsupervised cluster analysis confirmed increased B cell subsets harbored superior survival. In addition, high density of B cells was correlated with smaller tumor size and well differentiation. The results were validated in the independent cohort of 361 HCC patients. Intratumor infiltration of B cells is significantly impaired during HCC progression. High densities of tumor-infiltrating B cells imply a better clinical outcome. Therapies designed to target B cells may be a novel strategy in HCC.

Early T Follicular Helper Cell Responses and Germinal Center Reactions Are Associated with Viremia Control in Immunized Rhesus Macaques

T follicular helper (T_FH) cells are fundamental in germinal center (GC) maturation and selection of antigen-specific B cells within secondary lymphoid organs. GC-resident T_FH cells have been fully characterized in human immunodeficiency virus (HIV) infection. However, the role of GC T_FH cells in GC B cell responses following various simian immunodeficiency virus (SIV) vaccine regimens in rhesus macaques (RMs) has not been fully investigated. We characterized GC T_FH cells of RMs over the course of a mucosal/systemic vaccination regimen to elucidate GC formation and SIV humoral response generation. Animals were mucosally primed twice with replicating adenovirus type 5 host range mutant (Ad5hr)-SIV recombinants and systemically boosted with ALVAC-SIV_M766Gag/Pro/gp120-TM and SIV_M766&CG7V gD-gp120 proteins formulated in alum hydroxide (ALVAC/Env) or DNA encoding SIVenv/SIVGag/rhesus interleukin 12 (IL-12) plus SIV_M766&CG7V gD-gp120 proteins formulated in alum phosphate (DNA&Env). Lymph nodes were biopsied in macaque subgroups prevaccination and at day 3, 7, or 14 after the 2nd Ad5hr-SIV prime and the 2nd vector/Env boost. Evaluations of GC T_FH and GC B cell dynamics including correlation analyses supported a significant role for early GC T_FH cells in providing B cell help during initial phases of GC formation. GC T_FH responses at day 3 post-mucosal priming were consistent with generation of Env-specific memory B cells in GCs and elicitation of prolonged Env-specific humoral immunity in the rectal mucosa. GC Env-specific memory B cell responses elicited early post-systemic boosting correlated significantly with decreased viremia postinfection. Our results highlight the importance of early GC T_FH cell responses for robust GC maturation and generation of long-lasting SIV-specific humoral responses at mucosal and systemic sites. Further investigation of GC T_FH cell dynamics should facilitate development of an efficacious HIV vaccine.IMPORTANCE The modest HIV protection observed in the human RV144 vaccine trial associated antibody responses with vaccine efficacy. T follicular helper (T_FH) cells are CD4⁺ T cells that select antibody secreting cells with high antigenic affinity in germinal centers (GCs) within secondary lymphoid organs. To evaluate the role of T_FH cells in eliciting prolonged virus-specific humoral responses, we vaccinated rhesus macaques with a combined mucosal prime/systemic boost regimen followed by repeated low-dose intrarectal challenges with SIV, mimicking human exposure to HIV-1. Although the vaccine regimen did not prevent SIV infection, decreased viremia was observed in the immunized macaques. Importantly, vaccine-induced T_FH responses elicited at day 3 postimmunization and robust GC maturation were strongly associated. Further, early T_FH-dependent SIV-specific B cell responses were also correlated with decreased viremia. Our findings highlight the contribution of early vaccine-induced GC T_FH responses to elicitation of SIV-specific humoral immunity and implicate their participation in SIV control.

The Risks and Benefits of Immune Checkpoint Blockade in Anti-AChR Antibody-Seropositive Non-Small Cell Lung Cancer Patients

Background: Anti-programmed cell death 1 (PD-1) monoclonal antibodies (Abs) unleash an immune response to cancer. However, a disruption of the immune checkpoint function by blocking PD-1/PD-ligand 1(PD-L1) signaling may trigger myasthenia gravis (MG) as a life-threatening immune-related adverse event. MG is a neuromuscular disease and is closely associated with being positive for anti-acetylcholine receptor (anti-AChR) Abs, which are high specific and diagnostic Abs for MG. Methods: A 72-year-old man was diagnosed with chemotherapy-refractory lung squamous cell carcinoma and nivolumab was selected as the third-line regimen. We describe the first report of an anti-AChR Ab-seropositive lung cancer patient achieving a durable complete response (CR) to an anti-PD-1 antibody therapy. To further explore this case, we performed multiplex immunofluorescence analysis on a pretreatment tumor. Results: The patient achieved a durable CR without developing MG. However, the levels of anti-AChR Abs were elevated during two years of anti-PD-1 antibody therapy. The tumor of the subclinical MG patient had high PD-L1 expression and an infiltrated–inflamed tumor immune microenvironment. Conclusions: This study suggests that immune checkpoint inhibitors can be safely used and provide the benefits for advanced cancer patients with immunologically ‘hot’ tumor even if anti-AChR Abs are positive. Although careful monitoring clinical manifestation in consultation with neurologist is needed, immune checkpoint inhibitors should be considered as a treatment option for asymptomatic anti-AChR Ab-seropositive cancer patients.

Inducible IFN-γ Expression for MHC-I Upregulation in Devil Facial Tumor Cells

The Tasmanian devil facial tumor (DFT) disease has led to an 80% reduction in the wild Tasmanian devil (Sarcophilus harrisii) population since 1996. The limited genetic diversity of wild devils and the lack of MHC-I expression on DFT cells have been implicated in the lack of immunity against the original DFT clonal cell line (DFT1). Recently, a second transmissible tumor of independent origin (DFT2) was discovered. Surprisingly, DFT2 cells do express MHC-I, but DFT2 cells appear to be on a trajectory for reduced MHC-I expression in vivo. Thus, much of the ongoing vaccine-development efforts and conservation plans have focused on MHC-I. A major limitation in conservation efforts is the lack of species-specific tools to understand Tasmanian devil gene function and immunology. To help fill this gap, we developed an all-in-one Tet-Off vector system to regulate expression of IFN-γ in DFT cells (DFT1.Tet/IFN-γ). IFN-γ can have negative effects on cell proliferation and viability; thus, doxycycline was used to suppress IFN-γ production whilst DFT1.Tet/IFN-γ cells were expanded in cell culture. Induction of IFN-γ following removal of doxycycline led to upregulation of MHC-I but also the inhibitory checkpoint molecule PD-L1. Additionally, DFT1.Tet/IFN-γ cells were capable of stimulating MHC-I upregulation on bystander wild type DFT cells in co-culture assays in vitro. This system represents a major step forward in DFT disease immunotherapy and vaccine development efforts, and ability to understand gene function in devils. Importantly, the techniques are readily transferable for testing gene function in DFT2 cells and other non-traditional species.

Immune checkpoint blockade and its combination therapy with small-molecule inhibitors for cancer treatment

Initially understood for its physiological maintenance of self-tolerance, the immune checkpoint molecule has recently been recognized as a promising anti-cancer target. There has been considerable interest in the biology and the action mechanism of the immune checkpoint therapy, and their incorporation with other therapeutic regimens. Recently the small-molecule inhibitor (SMI) has been identified as an attractive combination partner for immune checkpoint inhibitors (ICIs) and is becoming a novel direction for the field of combination drug design. In this review, we provide a systematic discussion of the biology and function of major immune checkpoint molecules, and their interactions with corresponding targeting agents. With both preclinical studies and clinical trials, we especially highlight the ICI + SMI combination, with its recent advances as well as its application challenges.

Immune Checkpoint Inhibitors in Pediatric Solid Tumors: Status in 2018

Background

Checkpoint inhibitors have transformed the treatment of cancer in adults. This class of drugs has demonstrated encouraging results in various malignancies such as metastatic melanoma, bladder cancer, renal cancer, and non-small cell lung carcinoma. However, researchers have only begun investigating the effectiveness and tolerability of checkpoint inhibitors in pediatric patients.

Methods

We conducted a review of PubMed indexed literature and clinicaltrials.gov using combinations of the keywords checkpoint, inhibitor, pediatric, CTLA-4 (cytotoxic T lymphocyte antigen-4), PD-1 (programmed cell death-1), and PD-L1 (programmed cell death receptor-1 ligand) to find every recently completed and ongoing trial evaluating checkpoint inhibitors in patients younger than 21 years old. Pertinent articles and clinical trials discussing the role of immune checkpoint inhibitors in the pediatric population were selected for final analysis and manuscript citation.

Results

This review presents an overview of the cellular mechanisms involved in checkpoint inhibition and of studies evaluating checkpoint inhibitors in humans. The review also details results and side effects from studies conducted with pediatric patients, current pediatric clinical trials, and future implications.

Conclusion

Immune checkpoint inhibitors have the potential to further therapeutic advances in pediatric oncology; however, we need more clinical trials and combination drug strategies targeted toward pediatric cancers.

Genomics of response to immune checkpoint therapies for cancer: implications for precision medicine

Immune checkpoint blockade (ICB) therapies, which potentiate the body's natural immune response against tumor cells, have shown immense promise in the treatment of various cancers. Currently, tumor mutational burden (TMB) and programmed death ligand 1 (PD-L1) expression are the primary biomarkers evaluated for clinical management of cancer patients across histologies. However, the wide range of responses has demonstrated that the specific molecular and genetic characteristics of each patient's tumor and immune system must be considered to maximize treatment efficacy. Here, we review the various biological pathways and emerging biomarkers implicated in response to PD-(L)1 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) therapies, including oncogenic signaling pathways, human leukocyte antigen (HLA) variability, mutation and neoantigen burden, microbiome composition, endogenous retroviruses (ERV), and deficiencies in chromatin remodeling and DNA damage repair (DDR) machinery. We also discuss several mechanisms that have been observed to confer resistance to ICB, such as loss of phosphatase and tensin homolog (PTEN), loss of major histocompatibility complex (MHC) I/II expression, and activation of the indoleamine 2,3-dioxygenase 1 (IDO1) and transforming growth factor beta (TGFβ) pathways. Clinical trials testing the combination of PD-(L)1 or CTLA-4 blockade with molecular mediators of these pathways are becoming more common and may hold promise for improving treatment efficacy and response. Ultimately, some of the genes and molecular mechanisms highlighted in this review may serve as novel biological targets or therapeutic vulnerabilities to improve clinical outcomes in patients.

PD-1 immunobiology in systemic lupus erythematosus

Programmed death (PD)-1 receptors and their ligands have been identified in the pathogenesis and development of systemic lupus erythematosus (SLE). Two key pathways, toll-like receptor and type I interferon, are significant to SLE pathogenesis and modulate the expression of PD-1 and the ligands (PD-L1, PD-L2) through activation of NF-κB and/or STAT1. These cell signals are regulated by tyrosine kinase (Tyro, Axl, Mer) receptors (TAMs) that are aberrantly activated in SLE. STAT1 and NF-κB also exhibit crosstalk with the aryl hydrocarbon receptor (AHR). Ligands to AHR are identified in SLE etiology and pathogenesis. These ligands also regulate the activity of the Epstein-Barr virus (EBV), which is an identified factor in SLE and PD-1 immunobiology. AHR is important in the maintenance of immune tolerance and the development of distinct immune subsets, highlighting a potential role of AHR in PD-1 immunobiology. Understanding the functions of AHR ligands as well as AHR crosstalk with STAT1, NF-κB, and EBV may provide insight into disease development, the PD-1 axis and immunotherapies that target PD-1 and its ligand, PD-L1.

PD-1 blockade partially recovers dysfunctional virus-specific B cells in chronic hepatitis B infection

Chronic HBV (CHB) infection suppresses virus-specific T cells, but its impact on humoral immunity has been poorly analyzed. Here, we developed a dual-staining method that utilizes hepatitis B virus (HBV) surface antigens (HBsAg) labeled with fluorochromes as "baits" for specific ex vivo detection of HBsAg-specific B cells and analysis of their quantity, function, and phenotype. We studied healthy vaccinated subjects (n = 18) and patients with resolved (n = 21), acute (n = 11), or chronic (n = 96) HBV infection and observed that frequencies of circulating HBsAg-specific B cells were independent of HBV infection status. In contrast, the presence of serum HBsAg affected function and phenotype of HBsAg-specific B cells that were unable to mature in vitro into Ab-secreting cells and displayed an increased expression of markers linked to hyperactivation (CD21lo) and exhaustion (PD-1). Importantly, B cell alterations were not limited to HBsAg-specific B cells, but affected the global B cell population. HBsAg-specific B cell maturation could be partially restored by a method involving the combination of the cytokines IL-2 and IL-21 and CD40L-expressing feeder cells and was further boosted by the addition of anti-PD-1 Abs. In conclusion, HBV infection has a marked impact on global and HBV-specific humoral immunity, yet HBsAg-specific B cells are amenable to a partial rescue by B cell-maturing cytokines and PD-1 blockade.

Circulating and intrahepatic antiviral B cells are defective in hepatitis B

B cells are increasingly recognized as playing an important role in the ongoing control of hepatitis B virus (HBV). The development of antibodies against the viral surface antigen (HBV surface antigen [HBsAgs]) constitutes the hallmark of resolution of acute infection and is a therapeutic goal for functional cure of chronic HBV (CHB). We characterized B cells directly ex vivo from the blood and liver of patients with CHB to investigate constraints on their antiviral potential. Unexpectedly, we found that HBsAg-specific B cells persisted in the blood and liver of many patients with CHB and were enriched for T-bet, a signature of antiviral potential in B cells. However, purified, differentiated HBsAg-specific B cells from patients with CHB had defective antibody production, consistent with undetectable anti-HBs antibodies in vivo. HBsAg-specific and global B cells had an accumulation of CD21-CD27- atypical memory B cells (atMBC) with high expression of inhibitory receptors, including PD-1. These atMBC demonstrated altered signaling, homing, differentiation into antibody-producing cells, survival, and antiviral/proinflammatory cytokine production that could be partially rescued by PD-1 blockade. Analysis of B cells within healthy and HBV-infected livers implicated the combination of this tolerogenic niche and HBV infection in driving PD-1hiatMBC and impairing B cell immunity.

Mucous Membrane Pemphigoid, Bullous Pemphigoid, and Anti-programmed Death-1/ Programmed Death-Ligand 1: A Case Report of an Elderly Woman With Mucous Membrane Pemphigoid Developing After Pembrolizumab Therapy for Metastatic Melanoma and Review of the Literature

An 83-year-old patient developed erosions and a blister of the gingival mucous membrane, 6 months after discontinuation of the anti-programmed death-1 (anti PD-1) pembrolizumab therapy administered for 10 months for a metastatic melanoma. A diagnosis of mild mucous membrane pemphigoid (MMP) was made. Complete remission of MMP was rapidly obtained with minimal therapy (doxycycline). MMP remained in complete remission after a 3-month follow-up since discontinuation of the doxycycline therapy and no evidence of relapse of the melanoma was observed after a 14-month follow-up since discontinuation of the pembrolizumab therapy. The widespread use of anti PD-1 and anti-programmed death-ligand-1 (PD-L1) in several malignancies reveals new adverse events. MMP describes a group of chronic, inflammatory, mucous membrane-predominant, subepithelial auto-immune blistering diseases. It is clinically distinct from bullous pemphigoid another autoimmune blistering disease but shares some immunological similarities with it. Twenty-nine cases of bullous pemphigoid associated with anti PD-1/PD-L1 have been reported in the literature and one of MMP. Here, we described the case of a MMP developed after pembrolizumab and discussed the accountability of anti PD-1/PD-L1 in our case and the previous reported bullous pemphigoid and MMP cases using the Begaud system scoring.

Proteomic Profiling of Native Unpassaged and Culture-Expanded Mesenchymal Stromal Cells (MSC)

Human culture-expanded mesenchymal stromal cells (MSC) are being considered for multiple therapeutic applications because of their regenerative and anti-inflammatory properties. Although a large number of MSC can be propagated from a small initial sample, several lines of evidence indicate that MSC lose their immunosuppressive and regenerative potency aftaer multiple passages. In this report, we use the FACSCAP Lyoplate proteomic analysis system to detect changes in cell surface protein expression of CD45^- /CD31^- /CD34^- /CD73⁺ /CD105⁺ stromal cells in unpassaged bone marrow (BM) and through 10 serial culture passages. We provide for the first time a detailed characterization of native unpassaged BM MSC (0.08% of BM mononuclear cells) as well as the changes that occur during the initial expansion. Adipogenic and osteogenic differentiative potential was determined though the serial passages and correlated with immunophenotypic changes and senescence. Among the most prominent were striking decreases in Fas ligand, CD98, CD205, and CD106, accompanied by a gain in the expression of CD49c, CD63, CD98, and class 1 and class 2 major histocompatibility complex (MHC) molecules. Other molecules that are down-modulated with later passage include CD24, CD54, CD59, CD243/P-glycoprotein, and CD273/PD-L2. Early senescence, as defined by the loss of replicative capacity occurring with the loss of differentiative capacity, increase in CDKN2A p16, and increased time to confluence, was accompanied by loss of the motility-associated metalloproteinase CD10 and the proliferation-associated transferrin receptor CD71. Among the strongest statistical associations were loss of MAC-inhibitory protein/CD59, loss of ICAM-1/CD54, and increase in CDKN2A as a function of increasing passage, as well as increased CD10 expression with adipogenic and osteogenic capacities. The data provide a clear set of markers that can be used to assess MSC quality. We suggest that clinically relevant numbers of highly functional low passage MSC can be manufactured starting with large quantities of BM, which are readily available from cadaveric organ donors.