Trans-vaccenic acid reprograms CD8+ T cells and anti-tumour immunity.

Diet-derived nutrients are inextricably linked to human physiology by providing energy and biosynthetic building blocks and by functioning as regulatory molecules. However, the mechanisms by which circulating nutrients in the human body influence specific physiological processes remain largely unknown. Here we use a blood nutrient compound library-based screening approach to demonstrate that dietary trans-vaccenic acid (TVA) directly promotes effector CD8+ T cell function and anti-tumour immunity in vivo. TVA is the predominant form of trans-fatty acids enriched in human milk, but the human body cannot produce TVA endogenously1. Circulating TVA in humans is mainly from ruminant-derived foods including beef, lamb and dairy products such as milk and butter2,3, but only around 19% or 12% of dietary TVA is converted to rumenic acid by humans or mice, respectively4,5. Mechanistically, TVA inactivates the cell-surface receptor GPR43, an immunomodulatory G protein-coupled receptor activated by its short-chain fatty acid ligands6-8. TVA thus antagonizes the short-chain fatty acid agonists of GPR43, leading to activation of the cAMP-PKA-CREB axis for enhanced CD8+ T cell function. These findings reveal that diet-derived TVA represents a mechanism for host-extrinsic reprogramming of CD8+ T cells as opposed to the intrahost gut microbiota-derived short-chain fatty acids. TVA thus has translational potential for the treatment of tumours.

Role of B cells in immune-related adverse events following checkpoint blockade.

Blockade of immune checkpoints has transformed the therapy of several cancers. However, immune-related adverse events (irAEs) have emerged as a major challenge limiting the clinical application of this approach. B cells are recognized as major players in the pathogenesis of human autoimmunity and have been successfully targeted to treat these disorders. While T cells have been extensively studied as therapeutic targets of immune checkpoint blockade (ICB), these checkpoints also impact B cell tolerance. Blockade of immune checkpoints in the clinic is associated with distinct changes in the B cell compartment that correlate with the development of irAEs. In this review, we focus on the possible role of humoral immunity, specifically human B cell subsets and autoantibodies in the pathogenesis of ICB-induced irAEs. There remains an unmet need to better understand the T:B cell cross talk underlying the activation of pathogenic B cells and the development of ICB-induced irAEs. Such studies may identify new targets or approaches to prevent or treat irAEs and improve the application of ICB therapy in cancer.

SARS-CoV-2 vaccination in the first year after hematopoietic cell transplant or chimeric antigen receptor T cell therapy: A prospective, multicenter, observational study.

BACKGROUND: The optimal timing of vaccination with SARS-CoV-2 vaccines after cellular therapy is incompletely understood. The objectives of this study are to determine whether humoral and cellular responses after SARS-CoV-2 vaccination differ if initiated <4 months versus 4-12 months after cellular therapy. METHODS: We conducted a multicenter prospective observational study at 30 cancer centers in the United States. SARS-CoV-2 vaccination was administered as part of routine care. We obtained blood prior to and after vaccinations at up to five time points and tested for SARS-CoV-2 spike (anti-S) IgG in all participants and neutralizing antibodies for Wuhan D614G, Delta B.1.617.2, and Omicron B.1.1.529 strains, as well as SARS-CoV-2-specific T cell receptors (TCRs), in a subgroup. RESULTS: We enrolled 466 allogeneic hematopoietic cell transplant (HCT; n=231), autologous HCT (n=170), and chimeric antigen receptor T cell (CAR-T cell) therapy (n=65) recipients between April 2021 and June 2022. Humoral and cellular responses did not significantly differ among participants initiating vaccinations <4 months vs 4-12 months after cellular therapy. Anti-S IgG ≥2,500 U/mL was correlated with high neutralizing antibody titers and attained by the last time point in 70%, 69%, and 34% of allogeneic HCT, autologous HCT, and CAR-T cell recipients, respectively. SARS-CoV-2-specific T cell responses were attained in 57%, 83%, and 58%, respectively. Pre-cellular therapy SARS-CoV-2 infection or vaccination were key predictors of post-cellular therapy immunity. CONCLUSIONS: These data support mRNA SARS-CoV-2 vaccination prior to, and reinitiation three to four months after, cellular therapies with allogeneic HCT, autologous HCT, and CAR-T cell therapy.

Tissue-resident memory-like T cells in tumor immunity: Clinical implications.

Tissue-resident memory (TRM) T cells are distinct population of non-circulating lymphocytes that play an important role in mediating regional immunity. TRM- like cells have now been identified as a component of tumor-infiltrating lymphocytes in several human tumors and correlate with outcome and response to immunotherapy. TRM cells have also been shown to mediate anti-tumor immunity in murine models. Biology of TRM cells has several implications for clinical cancer immunotherapy. Here we discuss newer insights into the biology of TRM T cells and discuss their implications for understanding the heterogeneity of immune microenvironment in tumors as well as improving the efficacy of cancer vaccines, immune-checkpoint blockade and adoptive cellular therapies in the clinic.

Venetoclax sensitivity in multiple myeloma is associated with B-cell gene expression.

Venetoclax is a highly potent, selective BCL2 inhibitor capable of inducing apoptosis in cells dependent on BCL2 for survival. Most myeloma is MCL1-dependent; however, a subset of myeloma enriched for translocation t(11;14) is codependent on BCL2 and thus sensitive to venetoclax. The biology underlying this heterogeneity remains poorly understood. We show that knockdown of cyclin D1 does not induce resistance to venetoclax, arguing against a direct role for cyclin D1 in venetoclax sensitivity. To identify other factors contributing to venetoclax response, we studied a panel of 31 myeloma cell lines and 25 patient samples tested for venetoclax sensitivity. In cell lines, we corroborated our previous observation that BIM binding to BCL2 correlates with venetoclax response and further showed that knockout of BIM results in decreased venetoclax sensitivity. RNA-sequencing analysis identified expression of B-cell genes as enriched in venetoclax-sensitive myeloma, although no single gene consistently delineated sensitive and resistant cells. However, a panel of cell surface makers correlated well with ex vivo prediction of venetoclax response in 21 patient samples and may serve as a biomarker independent of t(11;14). Assay for transposase-accessible chromatin sequencing of myeloma cell lines also identified an epigenetic program in venetoclax-sensitive cells that was more similar to B cells than that of venetoclax-resistant cells, as well as enrichment for basic leucine zipper domain-binding motifs such as BATF. Together, these data indicate that remnants of B-cell biology are associated with BCL2 dependency and point to novel biomarkers of venetoclax-sensitive myeloma independent of t(11;14).

The immune system in multiple myeloma and precursor states: Lessons and implications for immunotherapy and interception.

Multiple myeloma (MM) and its precursor monoclonal gammopathy of undetermined significance (MGUS) are distinct disorders that likely originate in the setting of chronic immune activation. Evolution of these lesions is impacted by cross-talk with both innate and adaptive immune systems of the host. Harnessing the immune system may, therefore, be an attractive strategy to prevent clinical malignancy. While clinical MM is characterized by both regional and systemic immune suppression and paresis, immune-based approaches, particularly redirecting T cells have shown remarkable efficacy in MM patients. Optimal application and sequencing of these new immune therapies and their integration into clinical MM management may depend on the underlying immune status, in turn impacted by host, tumor, and environmental features. Immune therapies carry the potential to achieve durable unmaintained responses and cures in MM.

Bone marrow microenvironments that contribute to patient outcomes in newly diagnosed multiple myeloma: A cohort study of patients in the Total Therapy clinical trials.

BACKGROUND: The tumor microenvironment (TME) is increasingly appreciated as an important determinant of cancer outcome, including in multiple myeloma (MM). However, most myeloma microenvironment studies have been based on bone marrow (BM) aspirates, which often do not fully reflect the cellular content of BM tissue itself. To address this limitation in myeloma research, we systematically characterized the whole bone marrow (WBM) microenvironment during premalignant, baseline, on treatment, and post-treatment phases. METHODS AND FINDINGS: Between 2004 and 2019, 998 BM samples were taken from 436 patients with newly diagnosed MM (NDMM) at the University of Arkansas for Medical Sciences in Little Rock, Arkansas, United States of America. These patients were 61% male and 39% female, 89% White, 8% Black, and 3% other/refused, with a mean age of 58 years. Using WBM and matched cluster of differentiation (CD)138-selected tumor gene expression to control for tumor burden, we identified a subgroup of patients with an adverse TME associated with 17 fewer months of progression-free survival (PFS) (95% confidence interval [CI] 5-29, 49-69 versus 70-82 months, χ2 p = 0.001) and 15 fewer months of overall survival (OS; 95% CI -1 to 31, 92-120 versus 113-129 months, χ2 p = 0.036). Using immunohistochemistry-validated computational tools that identify distinct cell types from bulk gene expression, we showed that the adverse outcome was correlated with elevated CD8+ T cell and reduced granulocytic cell proportions. This microenvironment develops during the progression of premalignant to malignant disease and becomes less prevalent after therapy, in which it is associated with improved outcomes. In patients with quantified International Staging System (ISS) stage and 70-gene Prognostic Risk Score (GEP-70) scores, taking the microenvironment into consideration would have identified an additional 40 out of 290 patients (14%, premutation p = 0.001) with significantly worse outcomes (PFS, 95% CI 6-36, 49-73 versus 74-90 months) who were not identified by existing clinical (ISS stage III) and tumor (GEP-70) criteria as high risk. The main limitations of this study are that it relies on computationally identified cell types and that patients were treated with thalidomide rather than current therapies. CONCLUSIONS: In this study, we observe that granulocyte signatures in the MM TME contribute to a more accurate prognosis. This implies that future researchers and clinicians treating patients should quantify TME components, in particular monocytes and granulocytes, which are often ignored in microenvironment studies.

Summary of the 2019 Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling.

The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup has organized an annual workshop focused on minimal residual disease (MRD) testing and immune profiling (IP) in multiple myeloma since 2016. In 2019, the workshop took place as an American Society of Hematology (ASH) Friday Scientific Workshop titled "Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma." This workshop focused on 4 main topics: the molecular and immunologic evolution of plasma cell disorders, development of new laboratory- and imaging-based MRD assessment approaches, chimeric antigen receptor T cell therapy research, and statistical and regulatory issues associated with novel clinical endpoints. In this report, we provide a summary of the workshop and discuss future directions.

Daratumumab in multiple myeloma.

The development of effective monoclonal antibodies for the treatment of myeloma has been a long journey of clinical and drug development. Identification of the right target antigen was a critical part of the process. CD38 as a target has been considered for some time, but clinically, daratumumab, a CD38 monoclonal antibody, was the first to be tested, and it has delivered the best clinical responses as a single agent to date. Its proven safety and efficacy in combination with other antimyeloma agents have led to several US Food and Drug Administration approvals for treating myeloma. Furthermore, the results of early trials in the induction therapy setting have demonstrated a beneficial role when it is added to the existing induction regimens. This review summarizes the importance of CD38 as a target and examines the clinical development of the CD38 monoclonal antibody daratumumab and its clinical significance in combination regimens in both patients with relapsed/refractory myeloma and patients with newly diagnosed myeloma.

Survival outcomes of patients with primary plasma cell leukemia (pPCL) treated with novel agents.

BACKGROUND: Primary plasma cell leukemia (pPCL) is an aggressive plasma cell disorder characterized by circulating plasma cells and a poor prognosis. Although patients who have pPCL benefit from the use of stem cell transplantation (SCT) and novel agents, their prognosis remains inferior to that of patients who have myeloma. METHODS: This was a retrospective analysis of 38 consecutive patients with pPCL who were diagnosed between October 2005 and July 2016 and were registered in the Winship Cancer Institute of Emory University database. Baseline characteristics as well as data about treatment and survival outcomes were collected. RESULTS: The median patient age at diagnosis was 58 years. All patients received a bortezomib-based induction regimen, and 92% received both bortezomib and an immunomodulatory drug (thalidomide or lenalidomide); in addition, 74% of patients underwent autologous SCT (ASCT), and 61% received maintenance therapy. The best response to first-line therapy was a partial response or better in 87% of patients, and 45% had a complete response (CR). The achievement of ≥CR was a predictor for prolonged progression-free survival (PFS) and overall survival (OS). The median PFS was 20 months, and the median OS was 33 months. PFS was prolonged in patients who underwent ASCT compared with those who did not undergo ASCT (25 vs 6 months; P = .004), and patients who received maintenance therapy after ASCT had prolonged median PFS (27 vs 11 months; P = .03) and a trend toward prolonged OS (median, 38 vs 22 months; P = .06) compared with those who did not receive maintenance therapy. CONCLUSIONS: The current data support the use of regimens combining novel agents in the upfront treatment of patients with pPCL as well as the role of ASCT and maintenance therapy for long-term disease control.

Clonal Immunoglobulin against Lysolipids in the Origin of Myeloma.

Antigen-driven selection has been implicated in the pathogenesis of monoclonal gammopathies. Patients with Gaucher's disease have an increased risk of monoclonal gammopathies. Here we show that the clonal immunoglobulin in patients with Gaucher's disease and in mouse models of Gaucher's disease-associated gammopathy is reactive against lyso-glucosylceramide (LGL1), which is markedly elevated in these patients and mice. Clonal immunoglobulin in 33% of sporadic human monoclonal gammopathies is also specific for the lysolipids LGL1 and lysophosphatidylcholine (LPC). Substrate reduction ameliorates Gaucher's disease-associated gammopathy in mice. Thus, long-term immune activation by lysolipids may underlie both Gaucher's disease-associated gammopathies and some sporadic monoclonal gammopathies.

Type II NKT Cells and Their Emerging Role in Health and Disease.

NKT cells recognize lipid Ags presented by a class I MHC-like molecule CD1d, a member of the CD1 family. Although most initial studies on NKT cells focused on a subset with semi-invariant TCR termed invariant NKT cells, the majority of CD1d-restricted lipid-reactive human T cells express diverse TCRs and are termed type II NKT cells. These cells constitute a distinct population of circulating and tissue-resident effector T cells with immune-regulatory properties. They react to a growing list of self- as well as non-self-lipid ligands, and share some properties with both invariant NKT and conventional T cells. An emerging body of evidence points to their role in the regulation of immunity to pathogens/tumors and in autoimmune/metabolic disorders. An improved understanding of the biology of these cells and the ability to manipulate their function may be of therapeutic benefit in diverse disease conditions.

MGUS to myeloma: a mysterious gammopathy of underexplored significance.

All cases of multiple myeloma (MM) are preceded by precursor states termed monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma (SMM). Genetic analyses of MGUS cells have provided evidence that it is a genetically advanced lesion, wherein tumor cells carry many of the genetic changes found in MM cells. Intraclonal heterogeneity is also established early during the MGUS phase. Although the genetic features of MGUS or SMM cells at baseline may predict disease risk, transition to MM involves altered growth of preexisting clones. Recent advances in mouse modeling of MGUS suggest that the clinical dormancy of the clone may be regulated in part by growth controls extrinsic to the tumor cells. Interactions of MGUS cells with immune cells, bone cells, and others in the bone marrow niche may be key regulators of malignant transformation. These interactions involve a bidirectional crosstalk leading to both growth-supporting and inhibitory signals. Because MGUS is already a genetically complex lesion, application of new tools for earlier detection should allow delineation of earlier stages, which we term as pre-MGUS Analyses of populations at increased risk of MGUS also suggest the possible existence of a polyclonal phase preceding the development of MGUS. Monoclonal gammopathy in several patients may have potential clinical significance in spite of low risk of malignancy. Understanding the entire spectrum of these disorders may have broader implications beyond prevention of clinical malignancy.

Prospective analysis of antigen-specific immunity, stem-cell antigens, and immune checkpoints in monoclonal gammopathy.

Blockade of immune checkpoints (ICPs) has led to impressive responses in cancer patients. However, the impact of preexisting immunity and ICPs on the risk of malignant transformation in human preneoplasia has not been prospectively studied. We prospectively analyzed antigen-specific B/T-cell immunity, immune composition of the tumor microenvironment, and the expression of a panel of ICPs on tumor and tumor-infiltrating immune cells in 305 patients with asymptomatic monoclonal gammopathy enrolled in S0120 under the auspices of SWOG. T-cell immunity against stem-cell antigen SOX2 and preserved humoral responses at study entry independently correlated with reduced risk of progression to clinical myeloma. Among the ICPs analyzed, expression of programmed death-ligand 1 (PD-L1) on tumor and infiltrating T cells correlated with increased risk of clinical malignancy, and blockade of this pathway boosted anti-SOX2 immunity in culture. These data suggest that stem-cell antigens and PD-L1 may be targeted for immunoprevention of myeloma. This trial was registered at www.clinicaltrials.gov as #NCT00900263.

Type II NKT-TFH cells against Gaucher lipids regulate B-cell immunity and inflammation.

Chronic inflammation including B-cell activation is commonly observed in both inherited (Gaucher disease [GD]) and acquired disorders of lipid metabolism. However, the cellular mechanisms underlying B-cell activation in these settings remain to be elucidated. Here, we report that ß-glucosylceramide 22:0 (ßGL1-22) and glucosylsphingosine (LGL1), 2 major sphingolipids accumulated in GD, can be recognized by a distinct subset of CD1d-restricted human and murine type II natural killer T (NKT) cells. Human ßGL1-22- and LGL1-reactive CD1d tetramer-positive T cells have a distinct T-cell receptor usage and genomic and cytokine profiles compared with the classical type I NKT cells. In contrast to type I NKT cells, ßGL1-22- and LGL1-specific NKT cells constitutively express T-follicular helper (TFH) phenotype. Injection of these lipids leads to an increase in respective lipid-specific type II NKT cells in vivo and downstream induction of germinal center B cells, hypergammaglobulinemia, and production of antilipid antibodies. Human ßGL1-22- and LGL1-specific NKT cells can provide efficient cognate help to B cells in vitro. Frequency of LGL1-specific T cells in GD mouse models and patients correlates with disease activity and therapeutic response. Our studies identify a novel type II NKT-mediated pathway for glucosphingolipid-mediated dysregulation of humoral immunity and increased risk of B-cell malignancy observed in metabolic lipid disorders.

Clinical and pharmacodynamic analysis of pomalidomide dosing strategies in myeloma: impact of immune activation and cereblon targets.

In preclinical studies, pomalidomide mediated both direct antitumor effects and immune activation by binding cereblon. However, the impact of drug-induced immune activation and cereblon/ikaros in antitumor effects of pomalidomide in vivo is unknown. Here we evaluated the clinical and pharmacodynamic effects of continuous or intermittent dosing strategies of pomalidomide/dexamethasone in lenalidomide-refractory myeloma in a randomized trial. Intermittent dosing led to greater tumor reduction at the cost of more frequent adverse events. Both cohorts experienced similar event-free and overall survival. Both regimens led to a distinct pattern but similar degree of mid-cycle immune activation, manifested as increased expression of cytokines and lytic genes in T and natural killer (NK) cells. Pomalidomide induced poly-functional T-cell activation, with increased proportion of coinhibitory receptor BTLA(+) T cells and Tim-3(+) NK cells. Baseline levels of ikaros and aiolos protein in tumor cells did not correlate with response or survival. Pomalidomide led to rapid decline in Ikaros in T and NK cells in vivo, and therapy-induced activation of CD8(+) T cells correlated with clinical response. These data demonstrate that pomalidomide leads to strong and rapid immunomodulatory effects involving both innate and adaptive immunity, even in heavily pretreated multiple myeloma, which correlates with clinical antitumor effects. This trial was registered at www.clinicaltrials.gov as #NCT01319422.

Combination therapy with anti-CTLA-4 and anti-PD-1 leads to distinct immunologic changes in vivo.

Combination therapy concurrently targeting PD-1 and CTLA-4 immune checkpoints leads to remarkable antitumor effects. Although both PD-1 and CTLA-4 dampen the T cell activation, the in vivo effects of these drugs in humans remain to be clearly defined. To better understand biologic effects of therapy, we analyzed blood/tumor tissue from 45 patients undergoing single or combination immune checkpoint blockade. We show that blockade of CTLA-4, PD-1, or combination of the two leads to distinct genomic and functional signatures in vivo in purified human T cells and monocytes. Therapy-induced changes are more prominent in T cells than in monocytes and involve largely nonoverlapping changes in coding genes, including alternatively spliced transcripts and noncoding RNAs. Pathway analysis revealed that CTLA-4 blockade induces a proliferative signature predominantly in a subset of transitional memory T cells, whereas PD-1 blockade instead leads to changes in genes implicated in cytolysis and NK cell function. Combination blockade leads to nonoverlapping changes in gene expression, including proliferation-associated and chemokine genes. These therapies also have differential effects on plasma levels of CXCL10, soluble IL-2R, and IL-1α. Importantly, PD-1 receptor occupancy following anti-PD-1 therapy may be incomplete in the tumor T cells even in the setting of complete receptor occupancy in circulating T cells. These data demonstrate that, despite shared property of checkpoint blockade, Abs against PD-1, CTLA-4 alone, or in combination have distinct immunologic effects in vivo. Improved understanding of pharmacodynamic effects of these agents in patients will support rational development of immune-based combinations against cancer.

Clinical, genomic, and imaging predictors of myeloma progression from asymptomatic monoclonal gammopathies (SWOG S0120).

All cases of clinical myeloma (CMM) are preceded by an asymptomatic monoclonal gammopathy (AMG), classified as either monoclonal gammopathy of undetermined significance (MGUS) or asymptomatic multiple myeloma (AMM). We analyzed data from AMG patients (n = 331) enrolled in a prospective, observational clinical trial (S0120). Baseline data from clinical variables, gene expression profiles (GEP) of purified tumor cells, and findings of magnetic resonance imaging (MRI) were correlated with the risk of progression to CMM requiring therapy. GEP of purified tumor cells revealed that all molecular subtypes of CMM are also represented in the AMG phase. An increased risk score (>-0.26) (based on a 70-gene signature, GEP70) was an independent predictor of the risk of progression to CMM. Combination of elevated serum free light chain, M-spike, and GEP70 risk score identified a subset with high risk (67% at 2 years) of progression to CMM requiring therapy. Importantly, absence of these factors in AMM patients predicted low risk similar to MGUS. Detection of multiple (>1) focal lesions by MRI also conferred an increased risk of progression. These data demonstrate that signatures associated with high-risk CMM impact disease risk and support inclusion of genomic analysis in the clinical management of AMGs.

Nanoparticle-mediated combinatorial targeting of multiple human dendritic cell (DC) subsets leads to enhanced T cell activation via IL-15-dependent DC crosstalk.

Most vaccines depend on coadministration of Ags and adjuvants that activate APCs. Nanoparticles (NPs) have emerged as an attractive vehicle for synchronized delivery of Ags and adjuvants to APCs and can be targeted to specific cell types, such as dendritic cells (DCs), which are potent APCs. Which subset of human DCs should be targeted for optimal activation of T cell immunity, however, remains unknown. In this article, we describe a poly-lactic-coglycolic acid-based NP platform, wherein avidin-decorated NPs can be targeted to multiple human DC subsets via biotinylated Abs. Both BDCA3(+) and monocyte-derived DC-SIGN(+) NP-loaded DCs were equally effective at generating Ag-specific human T cells in culture, including against complex peptide mixtures from viral and tumor Ags across multiple MHC molecules. Ab-mediated targeting of NPs to distinct DC subsets led to enhanced T cell immunity. However, combination targeting to both DC-SIGN and BDCA3(+) DCs led to significantly greater activation of T cells compared with targeting either DC subset alone. Enhanced T cell activation following combination targeting depended on DC-mediated cytokine release and was IL-15 dependent. These data demonstrate that simultaneous targeting of multiple DC subsets may improve NP vaccines by engaging DC crosstalk and provides a novel approach to improving vaccines against pathogens and tumors.