Clonal Cytotoxic T Cells in Myeloma

Natural Killer Cells and Cytotoxic T Cells: Complementary Partners against Microorganisms and Cancer

Natural killer (NK) cells and cytotoxic T (CD8+) cells are two of the most important types of immune cells in our body, protecting it from deadly invaders. While the NK cell is part of the innate immune system, the CD8+ cell is one of the major components of adaptive immunity. Still, these two very different types of cells share the most important function of destroying pathogen-infected and tumorous cells by releasing cytotoxic granules that promote proteolytic cleavage of harmful cells, leading to apoptosis. In this review, we look not only at NK and CD8+ T cells but also pay particular attention to their different subpopulations, the immune defenders that include the CD56+CD16dim, CD56dimCD16+, CD57+, and CD57+CD16+ NK cells, the NKT, CD57+CD8+, and KIR+CD8+ T cells, and ILCs. We examine all these cells in relation to their role in the protection of the body against different microorganisms and cancer, with an emphasis on their mechanisms and their clinical importance. Overall, close collaboration between NK cells and CD8+ T cells may play an important role in immune function and disease pathogenesis. The knowledge of how these immune cells interact in defending the body against pathogens and cancers may help us find ways to optimize their defensive and healing capabilities with methods that can be clinically applied.

The Involvement of LAG-3positive Plasma Cells in the Development of Multiple Myeloma

The Lymphocyte-Activation Protein 3 (LAG-3) inhibitory receptor is expressed on regulatory plasma cells (PCs). Micro-environmental cells that express LAG-3 were found to be increased during the progression of smoldering multiple myeloma (SMM). To assess the possible role of LAG-3 expression on regulatory PCs in patients with plasma cell dyscrasia. Purified Cluster of Differentiation 138 (CD138+) PCs from patients with premalignant conditions, active multiple myeloma (MM), and controls were analyzed for the expression of LAG-3 by flow cytometry. Autologous CD8+T cells were incubated with sorted LAG-3pos or LAG-3neg PCs for 24 h. The expression of granzyme (Grz) in CD8+T cells was assessed by flow cytometry. LAG-3 expression on PCs in active MM (newly diagnosed and relapse refractory MM) was significantly increased compared to monoclonal gammopathy of undetermined significance (MGUS)/ SMM. Grz expression was significantly decreased in CD8+T cells incubated with CD138+LAG-3pos PCs, compared to CD138+LAG-3neg PCs in patients with plasma cell dyscrasia, n = 31, p = 0.0041. LAG-3 expression on malignant PCs can be involved in the development of MM from MGUS by decreasing the expression of Grz in CD8+T cells.

Treg and Oligoclonal Expansion of Terminal Effector CD8+ T Cell as Key Players in Multiple Myeloma

The classical paradigm of host-tumor interaction, i.e. elimination, equilibrium, and escape (EEE), is reflected in the clinical behavior of myeloma which progresses from the premalignant condition, Monoclonal Gammopathy of Unknown Significance (MGUS). Despite the role of other immune cells, CD4⁺ regulatory T cells (Treg) and cytotoxic CD8⁺ T cells have emerged as the dominant effectors of host control of the myeloma clone. Progression from MGUS to myeloma is associated with alterations in Tregs and terminal effector CD8⁺ T cells (T_TE). These changes involve CD39 and CD69 expression, affecting the adenosine pathway and residency in the bone marrow (BM) microenvironment, together with oligoclonal expansion within CD8⁺ T_TE cells. In this mini-review article, in the context of earlier data, we summarize our recent understanding of Treg involvement in the adenosine pathway, the significance of oligoclonal expansion within CD8⁺ T_TE cells and BM-residency of CD8⁺ T_TE cells in MGUS and newly diagnosed multiple myeloma patients.

Differences in the Immune Response of the Nonmetastatic Axillary Lymph Nodes between Triple-Negative and Luminal A Breast Cancer Surrogate Subtypes

Breast cancer (BC) comprises four immunohistochemical surrogate subtypes of which triple-negative breast cancer (TNBC) has the highest risk of mortality. Axillary lymph nodes (ALNs) are the regions where BC cells first establish before distant metastasis, and the presence of tumor cells in the ALN causes an immune tolerance profile that contrasts with that of the nonmetastatic ALN (ALN^-). However, few studies have compared the immune components of the ALNs^- in BC subtypes. The present study aimed to determine whether differences between immune populations in the primary tumor and ALNs^- were associated with the luminal A or TNBC subtype. We evaluated a retrospective cohort of 144 patients using paraffin-embedded biopsies. The TNBC samples tended to have a higher histologic grade and proliferation index and had higher levels of immune markers compared with luminal A in primary tumors and ALNs^-. Two methods for validating the multivariate analysis found that histologic grade, intratumoral S100 dendritic cells, and CD8 T lymphocytes and CD57 natural killer cells in the ALNs^- were factors associated with TNBC, whereas CD83 dendritic cells in the ALNs^- were associated with the luminal A subtype. In conclusion, we found that intratumoral regions and ALNs^- of TNBC contained higher concentrations of markers related to immune tolerance than luminal A. This finding partially explains the worse prognosis of patients with TNBC.

Actors on the Scene: Immune Cells in the Myeloma Niche

Two mechanisms are involved in the immune escape of cancer cells: the immunoediting of tumor cells and the suppression of the immune system. Both processes have been revealed in multiple myeloma (MM). Complex interactions between tumor plasma cells and the bone marrow (BM) microenvironment contribute to generate an immunosuppressive milieu characterized by high concentration of immunosuppressive factors, loss of effective antigen presentation, effector cell dysfunction, and expansion of immunosuppressive cell populations, such as myeloid-derived suppressor cells, regulatory T cells and T cells expressing checkpoint molecules such as programmed cell death 1. Considering the great immunosuppressive impact of BM myeloma microenvironment, many strategies to overcome it and restore myeloma immunosurveillance have been elaborated. The most successful ones are combined approaches such as checkpoint inhibitors in combination with immunomodulatory drugs, anti-monoclonal antibodies, and proteasome inhibitors as well as chimeric antigen receptor (CAR) T cell therapy. How best to combine anti-MM therapies and what is the optimal timing to treat the patient are important questions to be addressed in future trials. Moreover, intratumor MM heterogeneity suggests the crucial importance of tailored therapies to identify patients who might benefit the most from immunotherapy, reaching deeper and more durable responses.

MED15, transforming growth factor beta 1 (TGF-β1), FcγRIII (CD16), and HNK-1 (CD57) are prognostic biomarkers of oral squamous cell carcinoma

Owing to the high incidence and mortality of oral squamous cell carcinoma (OSCC), knowledge of its diagnostic and prognostic factors is of significant value. The biomarkers 'CD16, CD57, transforming growth factor beta 1 (TGF-β1), and MED15' can play crucial roles in tumorigenesis, and hence might contribute to diagnosis, prognosis, and treatment. Since there was no previous study on MED15 in almost all cancers, and since the studies on diagnostic/prognostic values of the other three biomarkers were a few in OSCC (if any) and highly controversial, this study was conducted. Biomarker expressions in all OSCC tissues and their adjacent normal tissues available at the National Tumor Bank (n = 4 biomarkers × [48 cancers + 48 controls]) were estimated thrice using qRT-PCR. Diagnostic values of tumors were assessed using receiver-operator characteristic (ROC) curves. Factors contributing to patients' survival over 10 years were assessed using multiple Cox regressions. ROC curves were used to estimate cut-off points for significant prognostic variables (α = 0.05). Areas under the curve pertaining to diagnostic values of all markers were non-significant (P > 0.15). Survival was associated positively with tumoral upregulation of TGF-β1 and downregulation of CD16, CD57, and MED15. It was also associated positively with younger ages, lower histological grades, milder Jacobson clinical TNM stages (and lower pathological Ns), smaller and thinner tumors, and surgery cases not treated with incisional biopsy (Cox regression, P < 0.05). The cut-off point for clinical stage -as the only variable with a significant area under the curve- was between the stages 2 and 3. Increased TGF-β1 and reduced CD16, CD57, and MED15 expressions in the tumor might independently favor the prognosis. Clinical TNM staging might be one of the most reliable prognostic factors, and stages above 2 can predict a considerably poorer prognosis.

Implementing liquid biopsies into clinical decision making for cancer immunotherapy

During the last decade, novel immunotherapeutic strategies, in particular antibodies directed against immune checkpoint inhibitors, have revolutionized the treatment of different malignancies leading to an improved survival of patients. Identification of immune-related biomarkers for diagnosis, prognosis, monitoring of immune responses and selection of patients for specific cancer immunotherapies is urgently required and therefore areas of intensive research. Easily accessible samples in particular liquid biopsies (body fluids), such as blood, saliva or urine, are preferred for serial tumor biopsies.

Although monitoring of immune and tumor responses prior, during and post immunotherapy has led to significant advances of patients’ outcome, valid and stable prognostic biomarkers are still missing. This might be due to the limited capacity of the technologies employed, reproducibility of results as well as assay stability and validation of results. Therefore solid approaches to assess immune regulation and modulation as well as to follow up the nature of the tumor in liquid biopsies are urgently required to discover valuable and relevant biomarkers including sample preparation, timing of the collection and the type of liquid samples. This article summarizes our knowledge of the well-known liquid material in a new context as liquid biopsy and focuses on collection and assay requirements for the analysis and the technical developments that allow the implementation of different high-throughput assays to detect alterations at the genetic and immunologic level, which could be used for monitoring treatment efficiency, acquired therapy resistance mechanisms and the prognostic value of the liquid biopsies.

Enumeration, functional responses and cytotoxic capacity of MAIT cells in newly diagnosed and relapsed multiple myeloma

Mucosal-associated invariant T (MAIT) cells are T cells that recognise vitamin-B derivative Ag presented by the MHC-related-protein 1 (MR1) antigen-presenting molecule. While MAIT cells are highly abundant in humans, their role in tumour immunity remains unknown. Here we have analysed the frequency and function of MAIT cells in multiple myeloma (MM) patients. We show that MAIT cell frequency in blood is reduced compared to healthy adult donors, but comparable to elderly healthy control donors. Furthermore, there was no evidence that MAIT cells accumulated at the disease site (bone marrow) of these patients. Newly diagnosed MM patient MAIT cells had reduced IFNγ production and CD27 expression, suggesting an exhausted phenotype, although IFNγ-producing capacity is restored in relapsed/refractory patient samples. Moreover, immunomodulatory drugs Lenalidomide and Pomalidomide, indirectly inhibited MAIT cell activation. We further show that cell lines can be pulsed with vitamin-B derivative Ags and that these can be presented via MR1 to MAIT cells in vitro, to induce cytotoxic activity comparable to that of natural killer (NK) cells. Thus, MAIT cells are reduced in MM patients, which may contribute to disease in these individuals, and moreover, MAIT cells may represent new immunotherapeutic targets for treatment of MM and other malignancies.

CD57 in human natural killer cells and T-lymphocytes

The CD57 antigen (alternatively HNK-1, LEU-7, or L2) is routinely used to identify terminally differentiated 'senescent' cells with reduced proliferative capacity and altered functional properties. In this article, we review current understanding of the attributes of CD57-expressing T-cells and NK cells in both health and disease and discuss how this marker can inform researchers about their likely functions in human blood and tissues in vivo. While CD57 expression on human lymphocytes indicates an inability to proliferate, these cells also display high cytotoxic potential, and CD57(pos) NK cells exhibit both memory-like features and potent effector functions. Accordingly, frequencies of CD57-expressing cells in blood and tissues have been correlated with clinical prognosis in chronic infections or various cancers and with human aging. Functional modulation of senescent CD57(pos) T-cells and mature CD57(pos) NK cells may therefore represent innovative strategies for protection against human immunological aging and/or various chronic diseases.

Absolute lymphocyte count as predictor of overall survival for patients with multiple myeloma treated with single autologous stem cell transplant

Post-autologous stem cell transplant (ASCT) studies have demonstrated that absolute lymphocyte count (ALC) recovery is associated with prolonged survival in some hematological malignancies. To assess whether ALC recovery has prognostic significance in patients with multiple myeloma (MM) undergoing single ASCT, we conducted a retrospective analysis of ALC at different time-points in patients with MM. In total 769 consecutive patients who underwent single ASCT from January 2000 to December 2007 were evaluated. An ALC of ≥ 1400 cells/μL at day 0, day 15 and day 90 significantly correlated with a better overall survival (OS) (median OS of 111, 90.7 and 84 months vs. 74, 70.5 and 65 months, respectively, p < 0.001 for all time-points). Multivariate analysis showed that ALC is an independent prognostic factor for OS after ASCT. In conclusion, ALC is a surrogate marker of the host immune system that correlates with better survival in patients with MM undergoing single ASCT. Immunomodulatory drugs, vaccination strategies and cellular therapies in MM should be investigated.

Functional Significance of CD57 Expression on Human NK Cells and Relevance to Disease

Historically, human NK cells have been identified as CD3(-)CD56(+)CD16(±) lymphocytes. More recently it has been established that CD57 expression defines functionally discrete sub-populations of NK cells. On T cells, CD57 expression has been regarded as a marker of terminal differentiation and (perhaps wrongly) of anergy and senescence. Similarly, CD57 expression seems to identify the final stages of peripheral NK cell maturation; its expression increases with age and is associated with chronic infections, particularly human cytomegalovirus infection. However, CD57(+) NK cells are highly cytotoxic and their presence seems to be beneficial in a number of non-communicable diseases. The purpose of this article is to review our current understanding of CD57 expression as a marker of NK cell function and disease prognosis, as well as to outline areas for further research.

Long-term survival in multiple myeloma is associated with a distinct immunological profile, which includes proliferative cytotoxic T-cell clones and a favourable Treg/Th17 balance

Despite improved outcomes in multiple myeloma (MM), a cure remains elusive. However, even before the current therapeutic era, 5% of patients survived >10 years and we propose that immune factors contribute to this longer survival. We identified patients attending our clinic, who had survived >10 years (n=20) and analysed their blood for the presence of T-cell clones, T-regulatory cells (Tregs) and T helper 17 (Th17) cells. These results were compared with MM patients with shorter follow-up and age-matched healthy control donors. The frequency of cytotoxic T-cell clonal expansions in patients with <10 years follow-up (MM patients) was 54% (n=144), whereas it was 100% (n=19/19) in the long-survivors (LTS-MM). T-cell clones from MM patients proliferated poorly in vitro, whereas those from LTS-MM patients proliferated readily (median proliferations 6.1% and 61.5%, respectively (P<0.0001)). In addition, we found significantly higher Th17 cells and lower Tregs in the LTS-MM group when compared with the MM group. These results indicate that long-term survival in MM is associated with a distinct immunological profile, which is consistent with decreased immune suppression.

Analysis of the immune system of multiple myeloma patients achieving long-term disease control by multidimensional flow cytometry

Multiple myeloma remains largely incurable. However, a few patients experience more than 10 years of relapse-free survival and can be considered as operationally cured. Interestingly, long-term disease control in multiple myeloma is not restricted to patients with a complete response, since some patients revert to having a profile of monoclonal gammopathy of undetermined significance. We compared the distribution of multiple compartments of lymphocytes and dendritic cells in the bone marrow and peripheral blood of multiple myeloma patients with long-term disease control (n=28), patients with newly diagnosed monoclonal gammopathy of undetermined significance (n=23), patients with symptomatic multiple myeloma (n=23), and age-matched healthy adults (n=10). Similarly to the patients with monoclonal gammopathy of undetermined significance and symptomatic multiple myeloma, patients with long-term disease control showed an expansion of cytotoxic CD8(+) T cells and natural killer cells. However, the numbers of bone marrow T-regulatory cells were lower in patients with long-term disease control than in those with symptomatic multiple myeloma. It is noteworthy that B cells were depleted in patients with monoclonal gammopathy of undetermined significance and in those with symptomatic multiple myeloma, but recovered in both the bone marrow and peripheral blood of patients with long-term disease control, due to an increase in normal bone marrow B-cell precursors and plasma cells, as well as pre-germinal center peripheral blood B cells. The number of bone marrow dendritic cells and tissue macrophages differed significantly between patients with long-term disease control and those with symptomatic multiple myeloma, with a trend to cell count recovering in the former group of patients towards levels similar to those found in healthy adults. In summary, our results indicate that multiple myeloma patients with long-term disease control have a constellation of unique immune changes favoring both immune cytotoxicity and recovery of B-cell production and homing, suggesting improved immune surveillance.

Clonal expansions of cytotoxic T cells exist in the blood of patients with Waldenström macroglobulinemia but exhibit anergic properties and are eliminated by nucleoside analogue therapy

T cells contribute to host-tumor interactions in patients with monoclonal gammopathies. Expansions of CD8+CD57+ T-cell receptor Vβ–positive (TCRVβ+)–restricted cytotoxic T-cell (CTL) clones are found in 48% of patients with multiple myeloma and confer a favorable prognosis. We now report that CTL clones with varying TCRVβ repertoire are present in 70% of patients with Waldenström macroglobulinemia (WM; n = 20). Previous nucleoside analog (NA) therapy, associated with increased incidence of transformation to aggressive lymphoma, significantly influenced the presence of TCRVβ expansions (χ2 = 11.6; P < .001), as 83% of patients without (n = 6) and only 7% with (n = 14) TCRVβ expansions had received NA. Clonality of CD3+CD8+CD57+TCRVβ+-restricted CTLs was confirmed by TCRVβ CDR3 size analysis and direct sequencing. The differential expression of CD3+CD8+CD57+TCRVβ+ cells was profiled using DNA microarrays and validated at mRNA and protein level. By gene set enrichment analysis, CTL clones expressed not only genes from cytotoxic pathways (GZMB, PRF1, FGFBP2) but also genes that suppress apoptosis, inhibit proliferation, arrest cell-cycle G1/S transition, and activate T cells (RAS, CSK, and TOB pathways). Proliferation tracking after stimulation confirmed their anergic state. Our studies demonstrate the incidence, NA sensitivity, and nature of clonal CTLs in WM and highlight mechanisms that cause anergy in these cells.

CD57+ T lymphocytes and functional immune deficiency

CD57(+) expression in T lymphocytes has been recognized for decades as a marker of in vitro replicative senescence. In recent years, accumulating evidences have pointed on the utility of this marker to measure functional immune deficiency in patients with autoimmune disease, infectious diseases, and cancers. We review here the relevant literature and implications in clinical settings.

High-throughput screening platform for anticancer therapeutic drug cytotoxicity

There are substances that kill cancer cells, but induce T cell proliferation, like thalidomide. To find more of these, a new anticancer drug screening strategy is vital. In this study we report the development of a differential cytotoxicity screening or evaluation platform using the CellTiter-Glo (Promega, Annandale, NSW, Australia) luminescent cell viability assay (ATP assay) and also the CellTiter 96 AQueous (Promega) one solution cell proliferation assay [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay]. The results suggested the platform consisting of the combination of the ATP assay be used for quantifying peripheral blood mononuclear cells, while the more economic MTS colorimetric assay is well suited to be used detecting cell viability of cancer cells. In addition, we found paclitaxel (Taxol, MP Biomedicals Australasia Pty Ltd., Seven Hills, NSW, Australia) to be a useful control for this routine screening methodology. Taxol exhibits the desirable in vitro feature of differential cytotoxicity that spares the immunological cells, when used at a concentration that will kill the majority of the cancer cell population.

Supplements for immune enhancement in hematologic malignancies

This brief review aims to discuss the various cellular immunological aspects and related mechanisms of the use of specific components from traditional herbal medicines. We begin with lessons learned from thalidomide as an effective single drug with multiple mechanisms of action to treat multiple myeloma. Examples of “supplements” or integrative therapy will be drawn from arsenic trioxide, medicinal mushrooms including Coriolus vesicular and Ganoderma lucidum, followed by the discussion of beta-glucans affecting various immunological important cellular subsets. Different classes of compounds may enhance distinct immune cell populations that might contribute to a multi-targeted holistic effects on anti-cancer treatment. Finally, we conclude by highlighting an herbal formulation PHY906 as a potential adjunct to chemotherapy that might become one of the first US Food and Drug Administration (FDA) approved oral herbal medicines for anti-cancer adjunct treatment.

A patient with paroxysmal nocturnal hemoglobinuria, T cell large granular lymphocyte clonal expansion, and monoclonal gammopathy of undetermined significance

Paroxysmal nocturnal hemoglobinuria (PNH) has been described in association separately with T cell large granular lymphocyte (LGL) clonal expansions and plasma cell dyscrasias. We describe a patient with anemia related to hemolytic PNH, with concurrent T cell LGL oligoclonal expansion and IgG lambda monoclonal gammopathy of undetermined significance. Peripheral blood flow cytometry revealed decreased expression of CD55 and CD59 on erythrocytes and decreased expression of CD55 and CD66 on neutrophils. An LGL population was present in the peripheral blood and was characterized as oligoclonal by polymerase chain reaction-based analysis of the T cell receptor gamma-chain variable region. Serum protein electrophoresis with immunofixation showed a low level IgG lambda monoclonal protein. We describe the diagnostic evaluation of this patient and provide a brief review of the reported associations among PNH, LGL clonal expansion, and monoclonal gammopathy.

Visualization of 5T33 myeloma cells in the C57BL/KaLwRij mouse: establishment of a new syngeneic murine model of multiple myeloma

OBJECTIVE

Lack of good models for in vivo detection of multiple myeloma (MM) cells hampers our understanding of the disease. Our objective was to establish a murine model for MM, allowing sensitive and labor-free tracing and quantification of MM cells in an immunocompetent host.

METHODS

5T33MM cells were retrovirally transduced, expressing enhanced green fluorescent protein (eGFP) and/or herpes simplex virus thymidine kinase (HSV-tk) as a control. Flow cytometric eGFP detection accuracy and sensitivity were assessed. Functional characteristics of transduced cells, including growth rate and production of IgG2b paraprotein and interleukin-6, were compared to those of nontransduced cells in vitro. For induction of MM, C57BL/KaLwRij mice were injected intravenously with transduced and nontransduced cells. Survival kinetics and distribution of eGFP cells in tissues were evaluated.

RESULTS

Flow cytometric eGFP detection was accurate at 1:1000 transduced/nontransduced cell ratio. Transduced and nontransduced 5T33MM cells exhibited similar growth rates, producing comparable IgG2b and interleukin-6 levels. Intravenous injection of both nontransduced and eGFP-transduced MM cells to C57BL/KaLwRij mice resulted in paraplegia. At the time of paraplegia, eGFP-transduced MM cells were detected substantially in the bone marrow, spleen, and liver, less in lymph nodes, but not in the thymus. The bone marrow of paraplegic mice contained higher eGFP-transduced MM cells compared to that of nonparaplegic animals.

CONCLUSIONS

In the established eGFP-5T33 MM model, MM cells are easily traced in an immunocompetent host. This model simplifies the analysis of homing pattern studies, the evaluation of therapeutic effects of various treatment approaches and contributes towards better understanding of MM.