Natural Killer T-like Cells: Immunobiology and Role in Disease.

CD56+ T cells are generally recognized as a distinct population of T cells and are categorized as NKT-like cells. Although our understanding of NKT-like cells is far from satisfactory, it has been shown that aging and a number of disease situations have impacted these cells. To construct an overview of what is currently known, we reviewed the literature on human NKT-like cells. NKT-like cells are highly differentiated T cells with "CD1d-independent" antigen recognition and MHC-unrestricted cell killing. The genesis of NKT-like cells is unclear; however, it is proposed that the acquisition of innate characteristics by T cells could represent a remodeling process leading to successful aging. Additionally, it has been shown that NKT-like cells may play a significant role in several pathological conditions, making it necessary to comprehend whether these cells might function as prognostic markers. The quantification and characterization of these cells might serve as a cutting-edge indicator of individual immune health. Additionally, exploring the mechanisms that can control their killing activity in different contexts may therefore result in innovative therapeutic alternatives in a wide range of disease settings.

Dynamics of Soluble Factors and Double-Negative T Cells Associated with Response to Renal Denervation in Resistant Hypertension Patients.

The role of the immune system, and hence inflammation, in the pathophysiology of hypertensive patients is not clear. Until now, most clinical and biochemical parameters have failed to predict a positive response to renal denervation (RDN). Our aim was to evaluate the immune response in a cohort of patients treated by RDN, through the analysis of cytokine, chemokine, and growth factor behavior. A population of 21 resistant hypertension patients, treated by RDN, was evaluated at six months and one year. Response was defined as a drop of ≥5 mmHg in ambulatory blood pressure monitoring. Sixty-seven percent and 81% of patients clinically responded after six months and one year, respectively. There were no complications or safety issues. Plasmatic levels of 45 cytokine, chemokine, and growth factors were quantified at four different times, pre- and post-procedure. Baseline characteristics were similar between groups, except that active smoking was more frequent in non-responders at one year. Regulated on activation, normal T cell expressed, and secreted (RANTES/CCL5) levels were significantly lower in responders, both at baseline and at 30 days (p = 0.037), and a level ≤15,496 pg/mL was the optimal cutoff, for prediction of a response. IL-15, IL-17A, IL-27, and leukemia inhibitory factor varied significantly in time, with an acute rise being observed 24 h after RDN. Our group has previously showed that HLA-DR+ double-negative (DN) T cells were significantly lower in responders. There was a positive correlation between IL-13, -27, and -4, and DN T cells, and a negative correlation between the latter and SDF-1α and TNF-α, at baseline. Low plasmatic levels of the chemokine RANTES/CCL5 was the most significant result associated with RDN response and may help to identify the best candidates among patients with true resistant hypertension. Pro-inflammatory cytokines correlated negatively with DN T cells in responders, a finding compatible with an enhanced inflammatory milieu present in this extremely high cardiovascular risk cohort.

Tumor-Infiltrating Lymphocytes and Cancer Markers in Osteosarcoma: Influence on Patient Survival.

Osteosarcoma (OST) is the most common type of high-grade primary bone tumor, which mainly affects young adults. The current standard of care for OST combines surgical resection with chemotherapy. The clinical outcomes and the current options to treat OST patients are unsatisfactory and novel treatment strategies are needed. The crosstalk between tumor cells and immune cells is essential to the OST microenvironment. Despite the efforts that have been made to address the importance of immune-related factors in OST, there is still a lot to understand. The purpose of the current study was to evaluate the tumor-infiltrating lymphocytes (TIL), the expression of proteins involved in tumor biology, and their impact on the clinical outcome of OST patients. We studied 93 samples of OST patients using immunohistochemistry and histomorphometry. We looked for the infiltration of CD3+, CD4+, CD8+, TIA1+ and CD20+ cells and for the expression of CD44 standard (CD44s) and variant 6 (CD44v6), CD95/Fas, Fas-L, p53 and p-glycoprotein. All the parameters were analyzed for the influence on the occurrence of death and metastasis, plus patient overall survival (OS) and progression-free survival (PFS). The effect of sex, age, tumor location (distal femur or proximal tibia) and the combination with neoadjuvant chemotherapy was also assessed. Our results suggest that the presence of tumor-infiltrating CD4+ cells provides protection to OST patients, and that CD8+ cells have a significant impact on the patient's overall survival (OS) and progression-free survival (PFS), which is more evident in male patients. In addition, a strong association between tumor-infiltrating CD4+ cells and the presence of CD44s expression in tumor samples was observed. Analysis of TIL and tumor markers related to tumor biology could be useful to stratify patients and monitor the response to therapy, as well as to assist with the development of immunotherapy strategies to improve the effects of cytotoxic TIL to eradicate the tumor cells.

The Role of Natural Killer Cells in Soft Tissue Sarcoma: Prospects for Immunotherapy.

Soft-tissue sarcomas (STS) represent about 80% of sarcomas, and are a heterogeneous group of rare and malignant tumors. STS arise from mesenchymal tissues and can grow into structures such as adipose tissue, muscles, nervous tissue and blood vessels. Morphological evaluation has been the standard model for the diagnosis of sarcomas, and even in samples with similar characteristics, they present a diversity in cytogenetic and genetic sequence alterations, which further increases the diversity of sarcomas. This variety is one of the main challenges for the classification and understanding of STS patterns, as well as for their respective treatments, which further decreases patient survival (<5 years). Despite some studies, little is known about the immunological profile of STS. As for the immunological profile of STS in relation to NK cells, there is also a shortage of studies. Observations made in solid tumors show that the infiltration of NK cells in tumors is associated with a good prognosis of the disease. Notwithstanding the scarcity of studies to characterize NK cells, their receptors, and ligands in STS, it is noteworthy that the progression of these malignancies is associated with altered NK phenotypes. Despite the scarcity of information on the function of NK cells, their phenotypes and their regulatory pathways in STS, the findings of this study support the additional need to explore NK cell-based immunotherapy in STS further. Some clinical trials, very tentatively, are already underway. STS clinical trials are still the basis for adoptive NK-cell and cytokine-based therapy.

Tumor and Peripheral Immune Status in Soft Tissue Sarcoma: Implications for Immunotherapy.

Soft Tissue Sarcomas (STS) are a heterogeneous and rare group of tumors. Immune cells, soluble factors, and immune checkpoints are key elements of the complex tumor microenvironment. Monitoring these elements could be used to predict the outcome of the disease, the response to therapy, and lead to the development of new immunotherapeutic approaches. Tumor-infiltrating B cells, Natural Killer (NK) cells, tumor-associated neutrophils (TANs), and dendritic cells (DCs) were associated with a better outcome. On the contrary, tumor-associated macrophages (TAMs) were correlated with a poor outcome. The evaluation of peripheral blood immunological status in STS could also be important and is still underexplored. The increased lymphocyte-to-monocyte ratio (LMR) and neutrophil-to-lymphocyte ratio (NLR), higher levels of monocytic myeloid-derived suppressor cells (M-MDSCs), and Tim-3 positive CD8 T cells appear to be negative prognostic markers. Meanwhile, NKG2D-positive CD8 T cells were correlated with a better outcome. Some soluble factors, such as cytokines, chemokines, growth factors, and immune checkpoints were associated with the prognosis. Similarly, the expression of immune-related genes in STS was also reviewed. Despite these efforts, only very little is known, and much research is still needed to clarify the role of the immune system in STS.

Type 2 and type 3 innate lymphoid cells at the maternal-fetal interface: implications in preterm birth.

BACKGROUND: Preterm birth (PTB) is one of the major causes of neonatal morbidity and mortality worldwide. It is commonly accepted that the act of giving birth is the final step in a proinflammatory signaling cascade, orchestrated by an intrauterine milieu coupled to hormonal cues. Consequently, the inflammatory process plays a pivotal role during the pathogenesis of human labor, both in term and preterm deliveries. The ability of innate lymphoid cells (ILCs) to act as pro-inflammatory mediators arose the interest to study their role in normal and pathological pregnancies. The aim of this work was to analyze the relative frequencies of ILCs subsets in pregnancy and the levels of IL-4, IL-17, IL-22, and IFN-γ as inflammatory mediators. Accordingly, we hypothesized that changes in the proportions of ILCs subpopulations could be related to preterm birth. METHODS: We analyzed 15 full-term delivery samples and six preterm delivery samples. In the full-term group (FTB) peripheral blood was taken during routine blood analysis, on 3 occasions: 1st, 2nd and 3rd trimester. After delivery, peripheral blood, cord blood and placenta were collected. In PTB group, peripheral blood samples were obtained on two occasions: before and 24 h after treatment with progesterone. We used flow cytometry to analyze ILCs in maternal peripheral blood, placenta, and cord blood samples. Maternal peripheral blood and cord blood samples were analyzed by enzyme-linked immunosorbent assay for IL-4, IL-17, IL-22, and IFN-γ plasma levels at the time of labor. RESULTS: We observed significantly increased relative frequencies of ILC2 and ILC3 in the decidua, as well as an increase of ILC2 in cord blood samples in PTB group, compared to FTB samples. We also found a decrease in IFN-γ in peripheral blood samples of the PTB group, suggesting a functional withdrawal. Additionally, IL-4, IL-17, IL-22 levels were similar in PTB and FTB groups, denoting a relevant role in mediating labor. CONCLUSION: Our results suggest that ILC2 and ILC3 play a role in PTB by mediating an inflammatory response. Further work is necessary to evaluate the importance of ILCs in the regulation of labor.

Immunotherapy and predictive immunologic profile: the tip of the iceberg.

The interplay between cancer and the immune system has been under investigation for more than a century. Immune checkpoint inhibitors have changed the outcome of several tumors; however, there is a significant percentage of patients presenting resistance to immunotherapy. Besides the action mechanism, it is essential to unravel this complex interplay between host immune system and tumorigenesis to determine an immune profile as a predictive factor to immune checkpoint blockade agents. Tumor expression of programmed death-ligand 1 (PD-L1), tumor mutational burden, or mismatch repair deficiency are recognized predictive biomarkers to immunotherapy but are insufficient to explain the response rates and heterogeneity across tumor sites. Therefore, it is crucial to explore the role of the tumor microenvironment in the diversity and clonality of tumor-infiltrating immune cells since different checkpoint molecules play an influential role in cytotoxic T cell activation. Moreover, cytokines, chemokines, and growth factors regulated by epigenetic factors play a complex part. Peripheral immune cells expressing PD-1/PD-L1 and the biologic roles of soluble immune checkpoint molecules are the subject of new lines of investigation. This article addresses some of the new molecules and mechanisms studied as possible predictive biomarkers to immunotherapy, linked with the concept of immune dynamics monitoring.

Activated double-negative T cells (CD3+CD4-CD8-HLA-DR+) define response to renal denervation for resistant hypertension.

PURPOSE: To explore the cellular immune response of patients with resistant hypertension treated with renal denervation (RDN). METHODS AND RESULTS: Twenty-three patients were included and blood samples were obtained in six timings, pre and post procedure. Response was evaluated at six-months and one year and was observed in 69.6% and 82.6% of patients, respectively. Absolute values of HLA-DR+ double negative (DN) T cells were significantly lower in the group of 'responders' at one year, and interaction between the timings were found in three T cell subsets (T CD4, T CD8 and naïve T CD8 cells), with the 'responders' tending to present with lower absolute values and little inter-timing variation. CONCLUSIONS: 'Responders' significantly present with lower absolute values of activated DN T cells and have lower and more stable values of total T CD8+, CD4+, and naïve T CD8+ cells. These cell types may be able to predict response to RDN.

NKT-Like (CD3+CD56+) Cells in Chronic Myeloid Leukemia Patients Treated With Tyrosine Kinase Inhibitors.

Therapy with Tyrosine Kinase Inhibitors (TKI) aiming stable deep molecular response is the gold standard to treat Chronic Myeloid Leukemia (CML). NKT-like cells (CD3+CD56+) combine characteristics of T and NK cells. The physiopathological role of these cells remains unknown although the literature refers their association with inflammation, autoimmune diseases, and cancer. Since the information regarding the role of NKT-like cells in CML is rare, we aimed at the characterization of these cells in CML patients treated with TKIs. Peripheral blood NKT-like cells from 48 CML patients and 40 healthy donors were analyzed by multiparametric flow cytometry. Functional tests consisting of co-culture with leukemic target cells (K562 cell line) were used to measure degranulation and cytokine production. Our results revealed that NKT-like cells are decreased in treated CML patients, although they present increased expression of activation markers (CD69 and HLA-DR), increased degranulation (CD107a) and impaired IFN-γ production. Significantly alterations on the expression of tumor recognition (NCRs and NKp80), and immune regulation receptors (LAG-3, TIM-3, and CD137) by NKT-like cells were observed in CML patients. Second generation TKIs increased cell activation (CD69) and decreased expression of NKp44 and NKp80 by NKT-like cells from CML patients when compared to Imatinib. CML patients that achieved deep molecular response (MR4.5) presented downregulation of NKp44 and LAG-3. Further studies are needed to clarify the role of these cells as biomarkers of therapy response and also to evaluate their value for discrimination of better candidates for sustained treatment-free remission after TKI discontinuation.

Effect of Age on NK Cell Compartment in Chronic Myeloid Leukemia Patients Treated With Tyrosine Kinase Inhibitors.

Natural killer (NK) cells are a very important component of the innate immune response involved in the lysis of virus infected and tumor cells. Aging has a profound impact in the frequency, phenotype and function of NK cells. Chronic Myeloid Leukemia (CML) is caused by the BCR-ABL gene formation encoding aberrant oncoprotein tyrosine kinase. Treatment with tyrosine kinase inhibitors (TKIs) induces durable deep molecular response. The response to treatment and life expectancy is lower in older patients with chronic phase of CML than in younger patients. In this work we analyse NK cells from TKI-treated CML patients and healthy controls stratified according to age. We have analyzed the expression of NK receptors, activation markers, NK cell differentiation in CD56bright and CD56dim NK cell subsets and the expression of CD107a and IFN-γ in NK cells stimulated with K562. Whereas significant differences on the phenotype and function of NK cells were found between middle-aged (35-65 years old) and elderly (older than 65) healthy individuals, NK cells from TKI-treated CML patients do not show significant differences related with age in most parameters studied, indicating that age is not a limitation of the NK cell recovery after treatment with TKI. Our results also revealed differences in the expression of NK receptors, activation markers and functional assays in NK cells from TKI-treated CML patients compared with age-matched healthy controls. These results highlight the relevance of NK cells in TKI-treated patients and the need of an extensive analysis of the effect of aging on NK cell phenotype and function in these patients in order to define new NK-cell based strategies directed to control CML progression and achieve long-term disease remission after TKI cessation.