Expression of KLRG1 and CD127 defines distinct CD8+ subsets that differentially impact patient outcome in follicular lymphoma

Decreased progenitor TCF1 + T-cells correlate with COVID-19 disease severity

COVID-19, caused by SARS-CoV-2, can lead to a severe inflammatory disease characterized by significant lymphopenia. However, the underlying cause for the depletion of T-cells in COVID-19 patients remains incompletely understood. In this study, we assessed the presence of different T-cell subsets in the progression of COVID-19 from mild to severe disease, with a focus on TCF1 expressing progenitor T-cells that are needed to replenish peripheral T-cells during infection. Our results showed a preferential decline in TCF1+ progenitor CD4 and CD8+ T-cells with disease severity. This decline was seen in various TCF1+ subsets including naive, memory and effector-memory cells, and surprisingly, was accompanied by a loss in cell division as seen by a marked decline in Ki67 expression. In addition, TCF1+ T-cells showed a reduction in pro-survival regulator, BcL2, and the appearance of a new population of TCF1 negative caspase-3 expressing cells in peripheral blood from patients with severe disease. The decline in TCF1+ T-cells was also seen in a subgroup of severe patients with vitamin D deficiency. Lastly, we found that sera from severe patients inhibited TCF1 transcription ex vivo which was attenuated by a blocking antibody against the cytokine, interleukin-12 (IL12). Collectively, our findings underscore the potential significance of TCF1+ progenitor T-cells in accounting for the loss of immunity in severe COVID-19 and outline an array of markers that could be used to identify disease progression.

Neoadjuvant immune checkpoint blockade enhances local and systemic tumor immunity in head and neck cancer

PURPOSE OF REVIEW

Neoadjuvant (presurgical) immune checkpoint blockade (ICB) has shown promising clinical activity in head and neck cancer and other cancers, including FDA approvals for neoadjuvant approaches for triple-negative breast cancer and nonsmall cell lung cancer. Here we will review recent data from clinical trials in head and neck squamous cell carcinoma (HNSCC), including mechanistic studies highlighting local and systemic effects on T cell-mediated immunity.

RECENT FINDINGS

A series of clinical trials of neoadjuvant ICB have documented evidence of clinical activity, including clinical to pathologic downstaging and pathologic response in a subset of patients. Also, emerging data suggest improved survival outcomes for patients with tumors responsive to neoadjuvant ICB. In depth mechanistic studies have documented intra-tumoral expansion of CD8 T cell populations characterized by tissue residency and cytotoxicity programs. Treatment also leads to expansion of activated CD8 T cells in the blood, many of which share TCR sequences with tumor-infiltrating T cells. The frequency of activated circulating CD8 T cell populations is correlated with the degree of pathologic response within tumors.

SUMMARY

Even a short duration of neoadjuvant immunotherapy can enhance local and systemic tumor-reactive T cell populations. Downstaging induced by neoadjuvant ICB can reduce the extent of surgical resection in this anatomically sensitive location.

Endoplasmic Reticulum Stress in Hypertension and Salt Sensitivity of Blood Pressure

PURPOSE OF REVIEW

Hypertension is a principal risk factor for cardiovascular morbidity and mortality, with its severity exacerbated by high sodium intake, particularly in individuals with salt-sensitive blood pressure. However, the mechanisms underlying hypertension and salt sensitivity are only partly understood. Herein, we review potential interactions in hypertension pathophysiology involving the immune system, endoplasmic reticulum (ER) stress, the unfolded protein response (UPR), and proteostasis pathways; identify knowledge gaps; and discuss future directions.

RECENT FINDINGS

Recent advancements by our research group and others reveal interactions within and between adaptive and innate immune responses in hypertension pathophysiology. The salt-immune-hypertension axis is further supported by the discovery of the role of dendritic cells in hypertension, marked by isolevuglandin (IsoLG) formation. Alongside these broadened understandings of immune-mediated salt sensitivity, the contributions of T cells to hypertension have been recently challenged by groups whose findings did not support increased resistance of Rag-1-deficient mice to Ang II infusion. Hypertension has also been linked to ER stress and the UPR. Notably, a holistic approach is needed because the UPR engages in crosstalk with autophagy, the ubiquitin proteasome, and other proteostasis pathways, that may all involve hypertension. There is a critical need for studies to establish cause and effect relationships between ER stress and the UPR in hypertension pathophysiology in humans and to determine whether the immune system and ER stress function mainly to exacerbate or initiate hypertension and target organ injury. This review of recent studies proposes new avenues for future research for targeted therapeutic interventions.

Unraveling the immunological landscape in acute pancreatitis progression to sepsis: insights from a Mendelian randomization study on immune cell traits

Background

Acute pancreatitis (AP) is a severe digestive system disorder with a significant risk of progressing to sepsis, a major cause of mortality. Unraveling the immunological pathways in AP is essential for developing effective treatments, particularly understanding the role of specific immune cell traits in this progression.

Methods

Employing a bidirectional two-sample Mendelian Randomization (MR) approach, this study first examined the causal relationship between AP and 731 immune cell traits to identify those significantly associated with AP. Subsequently, we explored the causal associations between 731 immune cell traits and sepsis. The analysis utilized extensive genome-wide association studies (GWAS) summary datasets, with a focus on identifying common immune cell traits with statistically significant causal associations between AP and sepsis.

Results

Our investigation identified 44 immune cell traits unidirectionally associated with AP and 36 traits unidirectionally associated with sepsis. Among these, CD127 on CD28+ CD45RA- CD8+ T cells emerged as a common mediator, accounting for 5.296% of the increased risk of sepsis in AP patients. This finding highlights the significant role of specific memory CD8+ T cells in the pathophysiology of AP and its progression to sepsis.

Conclusion

This study elucidates the critical role of specific immune cell traits, particularly CD127hi memory CD8+ T cells, in the progression of AP to sepsis. Our findings provide a foundation for future research into targeted immune-modulatory therapies, potentially improving patient outcomes in AP-related sepsis and offering new insights into the complex immunological dynamics of this condition.

The role of Bach2 in regulating CD8 + T cell development and function

Bach2 was initially discovered in B cells, where it was revealed to control the transcription involved in cell differentiation. Bach2 is intimately connected to CD8 + T lymphocytes in various differentiation states and subsets according to recent findings. Bach2 can regulate primitive T cells, stimulate the development and differentiation of memory CD8 + T cells, inhibit the differentiation of effector CD8 + T cells, and play a significant role in the exhaustion of CD8 + T cells. The appearance and development of diseases are tightly linked to irregular CD8 + T cell differentiation and function. Accordingly, Bach2 offers novel approaches and possible targets for the clinical treatment of associated disorders based on research on these pathways. Here, we summarize the role of Bach2 in the function and differentiation of CD8 + T cells and its potential clinical applications.

Bioengineered hydrogels enhance ex vivo preservation of patient-derived tumor explants for drug evaluation

Ex vivo patient-derived tumor slices (PDTS) are currently limited by short-term viability in culture. Here, we show how bioengineered hydrogels enable the identification of key matrix parameters that significantly enhance PDTS viability compared to conventional culture systems. As demonstrated using single-cell RNA sequencing and high-dimensional flow cytometry, hydrogel-embedded PDTS tightly preserved cancer, cancer-associated fibroblast, and various immune cell populations and subpopulations in the corresponding original tumor. Cell-cell communication networks within the tumor microenvironment, including immune checkpoint ligand-receptor interactions, were also maintained. Remarkably, our results from a co-clinical trial suggest hydrogel-embedded PDTS may predict sensitivity to immune checkpoint inhibitors (ICIs) in head and neck cancer patients. Further, we show how these longer term-cultured tumor explants uniquely enable the sampling and detection of temporal evolution in molecular readouts when treated with ICIs. By preserving the compositional heterogeneity and complexity of patient tumors, hydrogel-embedded PDTS provide a valuable tool to facilitate experiments targeting the tumor microenvironment.

TDP-43 pathology links innate and adaptive immunity in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is the most common fatal motor neuron disease. Approximately 90% of ALS patients exhibit pathology of the master RNA regulator, Transactive Response DNA Binding protein (TDP-43). Despite the prevalence TDP-43 pathology in ALS motor neurons, recent findings suggest immune dysfunction is a determinant of disease progression in patients. Whether TDP-43 pathology elicits disease-modifying immune responses in ALS remains underexplored. In this study, we demonstrate that TDP-43 pathology is internalized by antigen presenting cells, causes vesicle rupture, and leads to innate and adaptive immune cell activation. Using a multiplex imaging platform, we observed interactions between innate and adaptive immune cells near TDP-43 pathological lesions in ALS brain. We used a mass cytometry-based whole-blood stimulation assay to provide evidence that ALS patient peripheral immune cells exhibit responses to TDP-43 aggregates. Taken together, this study provides a novel link between TDP-43 pathology and ALS immune dysfunction, and further highlights the translational and diagnostic implications of monitoring and manipulating the ALS immune response.

Eribulin promotes proliferation of CD8+ T cells and potentiates T cell-mediated anti-tumor activity against triple-negative breast cancer cells

PURPOSE

Chemotherapeutic agents exert immunomodulatory effects on triple-negative breast cancer (TNBC) cells and immune cells. Eribulin favorably affects the immunological status of patients with breast cancer. However, the effects of eribulin on the immune cells remain unexplored. The aim of this study was to investigate the effects of eribulin on immune cells.

METHODS

Peripheral blood mononuclear cells (PBMCs) from healthy donors and mouse splenocytes were stimulated with anti-CD3 and anti-CD28 antibodies. The effects of eribulin and paclitaxel on cell proliferation and differentiation status were analyzed using flow cytometry. RNA sequencing was performed to assess alterations in gene expression in CD8+ T cells following eribulin and paclitaxel treatment. Using TNBC cell lines (MDA-MB-231, Hs578T, and MDA-MB-157), the anti-tumor activity of CD3/CD28-stimulated T cells combined with eribulin or paclitaxel was evaluated.

RESULTS

Eribulin did not affect CD3/CD28-stimulated PBMCs proliferation. However, eribulin significantly decreased the CD4/CD8 ratio in T cells, indicating that eribulin facilitates CD8+ T cell proliferation. Furthermore, eribulin significantly increased the frequency of less differentiated CD45RA+, CCR7+, and TCF1+ subsets of CD8+ T cells. RNA sequencing revealed that eribulin enhanced the expression of gene sets related to cell proliferation and immune responses. Moreover, eribulin augmented the anti-tumor effects of CD3/CD28-stimulated T cells against TNBC cells. These results were not observed in experiments using paclitaxel.

CONCLUSIONS

Eribulin promoted CD8+ T cell proliferation, repressed effector T cell differentiation, and harnessed T cell-mediated anti-tumor effects. These mechanisms may be one of the cues that eribulin can improve the immunological status of tumor-bearing hosts.

Engineered IL-7 synergizes with IL-12 immunotherapy to prevent T cell exhaustion and promote memory without exacerbating toxicity

Cancer immunotherapy is moving toward combination regimens with agents of complementary mechanisms of action to achieve more frequent and robust efficacy. However, compared with single-agent therapies, combination immunotherapies are associated with increased overall toxicity because the very same mechanisms also work in concert to enhance systemic inflammation and promote off-tumor toxicity. Therefore, rational design of combination regimens that achieve improved antitumor control without exacerbated toxicity is a main objective in combination immunotherapy. Here, we show that the combination of engineered, tumor matrix-binding interleukin-7 (IL-7) and IL-12 achieves remarkable anticancer effects by activating complementary pathways without inducing any additive immunotoxicity. Mechanistically, engineered IL-12 provided effector properties to T cells, while IL-7 prevented their exhaustion and boosted memory formation as assessed by tumor rechallenge experiments. The dual combination also rendered checkpoint inhibitor (CPI)-resistant genetically engineered melanoma model responsive to CPI. Thus, our approach provides a framework of evaluation of rationally designed combinations in immuno-oncology and yields a promising therapy.

Advances in Monitoring and Prognostication for Lymphoma by Flow Cytometry

Flow cytometry (FC) is a well-established method important in the diagnosis and subclassification of lymphoma. In this article, the role of FC in lymphoma prognostication will be explored, and the clinical role for FC minimal/measurable residual disease testing as a monitoring tool for mature lymphoma will be introduced. Potential pitfalls of monitoring for residual/recurrent disease following immunotherapy will be presented.

Efficacy of Immune Checkpoint Blockade and Biomarkers of Response in Lymphoma: A Narrative Review

Immune checkpoint blockade (ICB) has revolutionized the prognosis of several advanced-stage solid tumors. However, its success has been far more limited in hematological malignancies and is mostly restricted to classical Hodgkin lymphoma (cHL) and primary mediastinal B cell lymphoma (PMBCL). In patients with non-Hodgkin lymphoma (NHL), response to PD-1/PD-L1 ICB monotherapy has been relatively limited, although some subtypes are more sensitive than others. Numerous predictive biomarkers have been investigated in solid malignancies, such as PD-L1 expression, tumor mutational burden (TMB) and microsatellite instability (MSI), among others. This review aims to appraise the current knowledge on PD-1/PD-L1 ICB efficacy in lymphoma when used either as monotherapy or combined with other agents, and describes potential biomarkers of response in this specific setting.

PD-1 blockade potentiates neoadjuvant chemotherapy in NSCLC via increasing CD127+ and KLRG1+ CD8 T cells

The combination of PD-1 blockade with neoadjuvant chemotherapy (NAC) has achieved unprecedented clinical success in non-small cell lung cancer (NSCLC) compared to NAC alone, but the underlying mechanisms by which PD-1 blockade augments the effects of chemotherapy remain incompletely elucidated. Single-cell RNA sequencing was performed on CD45⁺ immune cells isolated from surgically resected fresh tumors of seven NSCLC patients receiving NAC or neoadjuvant pembrolizumab and chemotherapy (NAPC). Multiplex fluorescent immunohistochemistry was performed on FFPE tissues before and after NAC or NAPC from 65 resectable NSCLC patients, and results were validated with GEO dataset. NAC resulted in an increase only of CD20⁺ B cells, whereas NAPC increased the infiltration of CD20⁺ B cells, CD4⁺ T cells, CD4⁺CD127⁺ T cells, CD8⁺ T cells, CD8⁺CD127⁺ and CD8⁺KLRG1⁺ T cells. Synergistic increase in B and T cells promotes favorable therapeutic response after NAPC. Spatial distribution analysis discovered that CD8⁺ T cells and their CD127⁺ and KLRG1⁺ subsets were in closer proximity to CD4⁺ T/CD20⁺ B cells in NAPC versus NAC. GEO dataset validated that B-cell, CD4, memory, and effector CD8 signatures correlated with therapeutic responses and clinical outcomes. The addition of PD-1 blockade to NAC promoted anti-tumor immunity through T and B cells recruitment in the tumor microenvironment and induced tumor-infiltrating CD8⁺ T cells skewed toward CD127⁺ and KLRG1⁺ phenotypes, which may be assisted by CD4⁺ T cells and B cells. Our comprehensive study identified key immune cell subsets exerting anti-tumor responses during PD-1 blockade therapy and that may be therapeutically targeted to improve upon existing immunotherapies for NSCLC.

30-color full spectrum flow cytometry panel for deep immunophenotyping of T cell subsets in murine tumor tissue

This 30-color full spectrum flow cytometry panel was developed and optimized for in-depth analysis T cells immunophenotype in tumor microenvironment and peripheral lymphoid organs. The panel presented here first identify the main cell subsets including myeloid cells, B cells, NKT cells, γδ T cells, CD4⁺ T cells and CD8⁺ T cells. For CD4⁺ T cells or CD8⁺ T cells, the panel includes markers for further characterization by including a selection of activation status(CD44, CD62L, CD69, Ki67, CD127, KLRG1 and CXCR3), costimulatory/co-inhibitory molecules (ICOS, OX-40, PD-1, LAG3, TIM-3, CTLA-4 and TIGIT), pro-inflammatory/anti-inflammatory cytokines (IFN-γ, TNF-α and IL-10) and cytotoxic molecules (Perforin, Granzymes B and CD107a). The panel has been tested on the tumor infiltrating T cells and corresponding spleen T cells in B16-F10 murine melanoma models.

A Comprehensive Analysis of Immune Response in Patients with Non-Muscle-Invasive Bladder Cancer

BACKGROUND

Bladder carcinoma has elevated morbimortality due to its high recurrence and progression in localized disease. A better understanding of the role of the tumor microenvironment in carcinogenesis and response to treatment is needed.

METHODS

Peripheral blood and samples of urothelial bladder cancer and adjacent healthy urothelial tissue were collected from 41 patients and stratified in low- and high-grade urothelial bladder cancer, excluding muscular infiltration or carcinoma in situ. Mononuclear cells were isolated and labeled for flow cytometry analysis with antibodies aimed at identifying specific subpopulations within T lymphocytes, myeloid cells and NK cells.

RESULTS

In peripheral blood and tumor samples, we detected different percentages of CD4+ and CD8+ lymphocytes, monocyte and myeloid-derived suppressor cells, as well as differential expression of activation- and exhaustion-related markers. Conversely, only a significant increase in bladder total monocytes was found when comparing bladder and tumor samples. Interestingly, we identified specific markers differentially expressed in the peripheral blood of patients with different outcomes.

CONCLUSION

The analysis of host immune response in patients with NMIBC may help to identify specific markers that allow optimizing therapy and patient follow-up. Further investigation is needed to establish a strong predictive model.

Decoding CAR T cell phenotype using combinatorial signaling motif libraries and machine learning

Chimeric antigen receptor (CAR) costimulatory domains derived from native immune receptors steer the phenotypic output of therapeutic T cells. We constructed a library of CARs containing ~2300 synthetic costimulatory domains, built from combinations of 13 signaling motifs. These CARs promoted diverse human T cell fates, which were sensitive to motif combinations and configurations. Neural networks trained to decode the combinatorial grammar of CAR signaling motifs allowed extraction of key design rules. For example, non-native combinations of motifs that bind tumor necrosis factor receptor-associated factors (TRAFs) and phospholipase C gamma 1 (PLCγ1) enhanced cytotoxicity and stemness associated with effective tumor killing. Thus, libraries built from minimal building blocks of signaling, combined with machine learning, can efficiently guide engineering of receptors with desired phenotypes.

Phenotype, Function, and Clinical Significance of CD26+ and CD161+Tregs in Splenic Marginal Zone Lymphoma

PURPOSE

Regulatory T-cells (Treg) are essential to Tregs homeostasis and modulate the antitumor immune response in patients with lymphoma. However, the biology and prognostic impact of Tregs in splenic marginal zone lymphoma (SMZL) have not been studied.

EXPERIMENTAL DESIGN

Biopsy specimens from 24 patients with SMZL and 12 reactive spleens (rSP) from individuals without lymphoma were analyzed by using CITE-seq (cellular indexing of transcriptomes and epitopes by sequencing), CyTOF (mass cytometry) analysis, and flow cytometry to explore the phenotype, transcriptomic profile, and clinical significance of intratumoral Tregs and their subsets. The biological characteristics and cell signaling pathways of intratumoral Treg subsets were confirmed by in vitro functional assays.

RESULTS

We found that Tregs are more abundant in SMZL patients' spleens than rSP, and Tregs from patients with SMZL and rSP can be separated into CD161+Treg and CD26+Treg subsets. CD161+Tregs are increased in SMZL but have dysregulated immune function. We found that CD161+Treg and CD26+Tregs have unique gene expression and phenotypic profiles and are differentially correlated with patient outcomes. Specifically, increased CD161+Tregs are significantly associated with a favorable prognosis in patients with SMZL, whereas CD26+Tregs are associated with a poor prognosis. Furthermore, activation of the IL2/STAT5 pathway contributes to the induction of CD26+Tregs and can be reversed by STAT5 inhibition.

CONCLUSIONS

IL2/STAT5-mediated expansion of CD26+Tregs contributes to a poor clinical outcome in SMZL and may represent a therapeutic opportunity in this disease.

Effects of B-Cell Lymphoma on the Immune System and Immune Recovery after Treatment: The Paradigm of Targeted Therapy

B-cell lymphoma and lymphoproliferative diseases represent a heterogeneous and complex group of neoplasms that are accompanied by a broad range of immune regulatory disorder phenotypes. Clinical features of autoimmunity, hyperinflammation, immunodeficiency and infection can variously dominate, depending on the immune pathway most involved. Immunological imbalance can play a role in lymphomagenesis, also supporting the progression of the disease, while on the other hand, lymphoma acts on the immune system to weaken immunosurveillance and facilitate immunoevasion. Therefore, the modulation of immunity can have a profound effect on disease progression or resolution, which makes the immune system a critical target for new therapies. In the current therapeutic scenario enriched by chemo-free regimens, it is important to establish the effect of various drugs on the disease, as well as on the restoration of immune functions. In fact, treatment of B-cell lymphoma with passive immunotherapy that targets tumor cells or targets the tumor microenvironment, together with adoptive immunotherapy, is becoming more frequent. The aim of this review is to report relevant data on the evolution of the immune system during and after treatment with targeted therapy of B-cell lymphomas.