New approaches in the immunotherapy of haematological malignancies

Crosstalk between Metabolic Disorders and Immune Cells

Metabolic syndrome results from multiple risk factors that arise from insulin resistance induced by abnormal fat deposition. Chronic inflammation owing to obesity primarily results from the recruitment of pro-inflammatory M1 macrophages into the adipose tissue stroma, as the adipocytes within become hypertrophied. During obesity-induced inflammation in adipose tissue, pro-inflammatory cytokines are produced by macrophages and recruit further pro-inflammatory immune cells into the adipose tissue to boost the immune response. Here, we provide an overview of the biology of macrophages in adipose tissue and the relationship between other immune cells, such as CD4+ T cells, natural killer cells, and innate lymphoid cells, and obesity and type 2 diabetes. Finally, we discuss the link between the human pathology and immune response and metabolism and further highlight potential therapeutic targets for the treatment of metabolic disorders.

Immunotherapy in Multiple Myeloma Using Cancer-Testis Antigens

Context:

Multiple myeloma (MM) is a B-cell malignancy characterized by monoclonal expansion of abnormal plasma cells in the bone marrow. It accounts for 10% of hematological malignancies. Although patients respond to a wide range of anticancer modalities, relapse occurs in a significant number of the cases. Immunotherapeutic approaches have been evolved to tackle this problem. Cancer-testis antigens CTAs as a group of tumor-associated antigens are appropriate targets for cancer immunotherapy as they have restricted expression pattern in normal tissues except for testis which is an immune-privileged site. Expression of these antigens has been assessed in different malignancies including MM.

Evidence Acquisition:

We performed a computerized search of the MEDLINE/PubMed databases with key words: multiple myeloma, cancer-testis antigen, and cancer stem cell and immunotherapy.

Results:

Several CTAs including NY-ESO-1, MAGE and GAGE family have been shown to be expressed in MM patients. Cellular and humoral immune responses against these antigens have been detected in MM patients.

Conclusions:

The frequent and high expression level of CTAs in MM patients shows that these antigens can be applied as cancer biomarkers as well as targets for immunotherapy in these patients.

T-cell immune suppression in patients with hematologic malignancies: clinical implications

SUMMARY 

The reversion of immune suppression and restoration of T-cell function against leukemia remains a significant clinical challenge. However, the advent of improved antileukemia-specific T-cell induction and the generation of gene-modified T cells has extended cellular immunotherapy to hematological malignancies. Numerous immunotherapeutic protocols have been developed aiming to enhance antileukemia T-cell immune function, eliminate leukemic cells and prevent relapse. By contrast, abnormal expression of CTLA-4 and PD1/PD-L1 plays a critical role in effector T-cell responses and increases Treg suppressive activity in patients with tumors; therefore, blocking CTLA-4, PD1 and PD-L1 is a novel approach for immunotherapy.

Restricted TRBV repertoire in CD4+ and CD8+ T-cell subsets from CML patients

T-cell immunodeficiency is a common feature in cancer patients, which may relate to initiation and development of tumor. In expanding our previous observations in this area, we studied the repertoire of T-cell receptor beta variable region (TRBV) and T-cell proliferative history in CD4+ and CD8+ T cells from chronic myeloid leukemia (CML) patients. The expression and clonality analysis were performed by reverse transcription-polymerase chain reaction (RT-PCR) and GeneScan technique in peripheral blood mononuclear cells (PBMCs), CD4+ and CD8+ subsets of T cells. Nineteen CML cases in chronic phase were selected for this study and 17 healthy individuals served as controls. Marked restriction of TRBV repertoire was observed in both CD4+ and CD8+ T cells from CML. In most CML samples, clonally expanded T cells were identified in CD4+ and CD8+ T cells, predominantly in TRBV19 and TRBV21 (5/19) subfamilies. In conclusion, the restricted expression of TRBV subfamilies indicates the T-cell immunodeficiency in CML patients; however, clonally expanded T cells suggest a specific immune response to leukemia associated antigens.

Deficiency of CD3gamma, delta, epsilon, and zeta expression in T cells from AML patients

In order to elucidate the feature of T-cell receptor (TCR) signal transduction in T-cells from acute myeloid leukemia (AML), the expression levels of CD3gamma, delta, epsilon and zeta chain genes in CD3+ T cells were analyzed using real-time PCR. CD3+ T cells sorted from peripheral blood of 10 AML patients and 10 healthy donors were used in the study. Significantly lower expression levels of all four CD3gamma, delta, epsilon, and zeta chain genes were found in the AML samples. The expression pattern of the four CD3 chains was epsilon>gamma>delta>zeta in CD3+ T cells from AML samples, which was different from the healthy control group. In conclusion, the results provide a global gene expression profile of CD3gamma, delta, epsilon, and zeta chains in AML patients. Deficiency of all four CD3 gene expression levels might represent the feature related to T-cell immunodeficiency.

Dendritic cells (DCs) can be successfully generated from leukemic blasts in individual patients with AML or MDS: an evaluation of different methods

Myeloid-leukemic cells (AML, MDS, CML) can be differentiated to leukemia-derived dendritic cell [DC (DCleu)] potentially presenting the whole leukemic antigen repertoire without knowledge of distinct leukemia antigens and are regarded as promising candidates for a vaccination strategy. We studied the capability of 6 serum-free DC culture methods, chosen according to different mechanisms, to induce DC differentiation in 137 cases of AML and 52 cases of MDS. DC-stimulating substances were cytokines ("standard-medium", "MCM-Mimic", "cytokine-method"), bacterial lysates ("Picibanil"), double-stranded RNA ["Poly (I:C)"] or a cytokine bypass method ("Ca-ionophore"). The quality/quantity of DC generated was estimated by flow cytometry studying (co) expressions of "DC"antigens, costimulatory, maturation, and blast-antigens. Comparing these methods on average 15% to 32% DC, depending on methods used, could be obtained from blast-containing mononuclear cells (MNC) in AML/MDS cases with a DC viability of more than 60%. In all, 39% to 64% of these DC were mature; 31% to 52% of leukemic blasts could be converted to DCleu and DCleu-proportions in the suspension were 2% to 70% (13%). Average results of all culture methods tested were comparable, however not every given case of AML could be differentiated to DC with 1 selected method. However performing a pre-analysis with 3 DC-generating methods (MCM-Mimic, Picibanil, Ca-ionophore) we could generate DC in any given case. Functional analyses provided proof, that DC primed T cells to antileukemia-directed cytotoxic cells, although an anti-leukemic reaction was not achieved in every case. In summary our data show that a successful, quantitative DC/DCleu generation is possible with the best of 3 previously tested methods in any given case. Reasons for different functional behaviors of DC-primed T cells must be evaluated to design a practicable DC-based vaccination strategy.

Decreased level of recent thymic emigrants in CD4+ and CD8+T cells from CML patients

BACKGROUND

T-cell immunodeficiency is a common feature in cancer patients, which may relate to initiation and development of tumor. Based on our previous finding, to further characterize the immune status, T cell proliferative history was analyzed in CD4+ and CD8+ T cells from chronic myeloid leukemia (CML) patients.

METHODS

Quantitative analysis of deltaRec-psiJalpha signal joint T cell receptor excision circles (sjTRECs) was performed in PBMCs, CD3+, CD4+ and CD8+T cells by real-time PCR, and the analysis of 23 TRBV-D1 sjTRECs was performed by semi-nested PCR. Forty eight CML cases in chronic phase (CML-CP) were selected for this study and 17 healthy individuals served as controls.

RESULTS

The levels of deltaRec-psiJalpha sjTRECs in PBMCs, CD3+, CD4+, and CD8+ T cells were significantly decreased in CML patients, compared with control groups. Moreover, the numbers of detectable TRBV subfamily sjTRECs, as well as the frequency of particular TRBV-BD1 sjTRECs in patients with CML were significantly lower than those from healthy individuals.

CONCLUSIONS

We observed decreased levels of recent thymic emigrants in CD4+ and CD8+ T cells that may underlay the persistent immunodeficiency in CML patients.

Evolution of T-cell clonality in a patient with Ph-negative acute lymphocytic leukemia occurring after interferon and imatinib therapy for Ph-positive chronic myeloid leukemia

Introduction

The development of Philadelphia chromosome (Ph) negative acute leukemia/myelodysplastic syndrome (MDS) in patients with Ph-positive chronic myeloid leukemia (CML) is very rare. The features of restrictive usage and absence of partial T cell clones have been found in patients with CML. However, the T-cell clonal evolution of Ph-negative malignancies during treatment for CML is still unknown.

Objective

To investigate the dynamic change of clonal proliferation of T cell receptor (TCR) Vα and Vβ subfamilies in one CML patient who developed Ph-negative acute lymphoblastic leukemia (ALL) after interferon and imatinib therapy.

Methods

The peripheral blood mononuclear cells (PBMC) samples were collected at the 3 time points (diagnosis of Ph-positive chronic phase (CP) CML, developing Ph-negative ALL and post inductive chemotherapy (CT) for Ph-negative ALL, respectively). The CDR3 size of TCR Vα and Vβ repertoire were detected by RT-PCR. The PCR products were further analyzed by genescan to identify T cell clonality.

Results

The CML patient who achieved complete cytogenetic remission (CCR) after 5 years of IFN-α therapy suddenly developed Ph-negative ALL 6 months following switch to imatinib therapy. The expression pattern and clonality of TCR Vα/Vβ T cells changed in different disease stages. The restrictive expression of Vα/Vβ subfamilies could be found in all three stages, and partial subfamily of T cells showed clonal proliferation. Additionally, there have been obvious differences in Vα/Vβ subfamily of T cells between the stages of Ph-positive CML-CP and Ph-negative ALL. The Vα10 and Vβ3 T cells evolved from oligoclonality to polyclonality, the Vβ13 T cells changed from bioclonality to polyclonality, when Ph-negative ALL developed.

Conclusions

Restrictive usage and clonal proliferation of different Vα/Vβ subfamily T cells between the stages of Ph-positive CP and Ph-negative ALL were detected in one patient. These changes may play a role in Ph- negative leukemogenesis.

Reduced levels of recent thymic emigrants in acute myeloid leukemia patients

BACKGROUND

T cell immunodeficiency is a common feature in cancer patients, which may relate to initiation and development of tumor. Our previous study showed skewed expression of T cell receptor beta variable region (TRBV) subfamilies and clonal expansion of T cells in leukemia patients. In the present study, in order to further characterize the T cell immunity in acute myeloid leukemia (AML) patients, the level of recent thymic emigrants (RTE) was analyzed.

MATERIALS AND METHODS

Quantitative analysis of signal joint T cell recombination excision circles (deltaRec-psiJalpha sjTRECs) was performed in peripheral blood mononuclear cells (PBMCs) by real-time PCR (TaqMan), and the analysis of 23 TRBV-BD1 sjTRECs was performed by semi-nested PCR. Eighty-eight cases with AML were selected for this study; ten AML cases in complete remission (AML-CR) and 38 healthy individuals served as controls.

RESULTS

The levels of deltaRec-psiJalpha sjTRECs in PBMCs and CD3+ T cells were significantly decreased in AML patients, compared with healthy individuals and in patients in completive remission. Also the frequency of 23 TRBV-BD1 sjTRECs, and the number of detectable TRBV subfamily sjTRECs were significantly lower in AML patients than in healthy individuals. Moreover, the sjTRECs numbers and the frequency of TRBV-BD1 sjTRECs showed a progressive linear decline with age in AML patients.

CONCLUSIONS

The decreased numbers of universal (deltaRec-psiJalpha) and family-specific (TRBV-BD1) sjTRECs indicate that the severe T cell immunodeficiency in AML patients is associated with reduced levels of recent thymic emigrants. In patients achieving complete remission both sjTREC counts return to normal values indicating the recovery of thymic function. Better understanding of the mechanisms underlying persistent immunodeficiency in leukemia patients may lead to novel treatment strategies to enhance immune competence.

Vaccine with beta-defensin 2-transduced leukemic cells activates innate and adaptive immunity to elicit potent antileukemia responses

Murine beta-defensin 2 (MBD2) is a small antimicrobial peptide of the innate immune system. Recent study showed that MBD2 could not only recruit immature dendritic cells but also activate them by Toll-like receptor 4 and thus may provide a critical link between the innate immune system and the adaptive immune response. In this report, we examined the antileukemia activity of MBD2 in a murine model of acute lymphoid leukemia (ALL) L1210. L1210 cells were engineered to secrete biologically functional MBD2. MBD2-modified L1210 (L1210-MBD2) showed significantly reduced leukemogenecity, resulting in a 80% rate of complete leukemia rejection. Inoculation of mice with L1210-MBD2 induced enhanced CTL and natural killer (NK) activity and augmented interleukin-12 and IFN-gamma production. All the recovered mice from the inoculation showed a protective immunity to the following challenge with parental L1210 cells and generate leukemia-specific memory CTL. Vaccines with irradiated L1210-MBD2 cells could cure 50% leukemia-bearing mice. Depletion of CD8+ T cells but not CD4+ T cells completely abrogated the antileukemia activity of MBD2. Interestingly, NK cells were also required for the MBD2-mediated antileukemia response, although ALL generally display a high degree of resistance to NK-mediated lysis. Our results suggest that MBD2 can activate both innate and adaptive immunity to generate potent antileukemia response, and MBD2 immunotherapy warrants further evaluation as a potential treatment for ALL.

Ondansetron, dexamethasone and an NK1 antagonist block radiation sickness in mice

Radiation sickness is frequently observed in total body irradiation (TBI). We have reported that the kaolin ingestion behavior "pica" may be analogous to nausea and vomiting in mice. We evaluated the effects of anti-emetics on the prevention of radiation-induced pica in mice. After the intraperitoneal injection of ondansetron (OND: 2 mg/kg), dexamethasone (DEX: 2 mg/kg) or CP-99,994 (CP: 15 mg/kg), mice received 9 Gy of TBI, and then kaolin consumption was measured after 24 h. Radiation-induced pica was slightly inhibited by pretreatment with a single administration of OND or DEX, but not by CP (control: 0.69+/-0.19 g, OND: 0.33+/-0.06 g, DEX: 0.39+/-0.07 g, CP: 0.66+/-0.09 g); it was significantly inhibited by the combination treatment of OND and DEX (control: 0.55+/-0.09 g, OND+DEX: 0.30+/-0.06 g, OND+CP: 0.70+/-0.04 g, DEX+CP: 0.58+/-0.02 g). The combination of the three drugs completely abolished the behavior (control: 0.67+/-0.08 g, OND+DEX+CP: 0.10+/-0.05 g). These results suggest that radiation-induced pica in mice may be useful to evaluate drugs for treatment of radiation sickness and that the combination therapy of a serotonin 5-HT3 receptor antagonist and a glucocorticosteroid with a neurokinin NK1 receptor antagonist is effective in reducing the symptom.

Apoptotic killing of B-chronic lymphocytic leukemia tumor cells by allicin generated in situ using a rituximab-alliinase conjugate

Allicin, a highly active component from freshly crushed garlic, is produced upon the reaction of the small molecular weight molecule alliin, with the enzyme alliinase (EC 4.4.1.4). Because allicin was shown to be toxic to various mammalian cells in vitro, we devised a novel approach for the therapy of B-cell malignancies based on site-directed generation of allicin. Alliinase was conjugated to the monoclonal antibody rituximab, which recognizes the CD20 antigen, and the resulting conjugate was targeted to CD20+ B chronic lymphocytic leukemia (B-CLL) and other B-cell lymphomas. Upon addition of alliin, allicin was formed in situ, killing the CD20+ tumor B cells via apoptosis. Following a 72-hour treatment, an 85% and 96% reduction was observed in the number of viable B-CLL and EBV-transformed B cells, respectively. Using the human/mouse radiation chimera for the evaluation of allicin targeting in a preclinical animal model, we showed a significant reduction in the number of recovered B-CLL, mantle cell lymphoma, or EBV-transformed B cells. We conclude that our system offers a new powerful and less toxic therapy for B-CLL and other B-cell malignancies. Furthermore, combining alliinase with the appropriate monoclonal antibody may extend the application of this approach to other conditions in which the elimination of a specific cell population is desired.

A phase-I clinical trial of active immunotherapy for acute leukemia using inactivated autologous leukemia cells mixed with IL-2, GM-CSF, and IL-6

We evaluated the efficacy and toxicity of vaccination in 29 patients with relapsed or refractory acute leukemia using inactivated autologous leukemia cells combined with interleukin-2 (IL-2), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-6. MHC-I, MHC-II, and B7-1 expression status on the surface of leukemia cells and the cytokine profile of IFN-gamma and IL-10 in serum before and after vaccination was detected.

RESULTS

Five achieved a complete remission (CR) and six a partial remission (PR) in this vaccination procedure. Adverse effects were erythema, swelling erosion, and even ulcers at vaccination sites and low grade fever during the first three days of vaccination. No other significant side effects were observed. The expression of MHC-I and MHC-II on leukemia cells was 100% and 90% positive, respectively. B7-1 was exclusively expressed on some cases of M4 and M5. The efficacy of the vaccine was statistically associated with the expression status of B7-1 on leukemia cells (P < 0.01). The serum level of IL-10 reduced significantly in the five patients who achieved complete remission (CR) after vaccination as compared with when they were originally diagnosed (P < 0.01).

CONCLUSION

We presented here a promising immunotherapy in the treatment of acute leukemia, especially for F.A.B. M5.

Comments on the 2001 WHO proposal for the classification of haematopoietic neoplasms

In the preface, the World Health Organization (WHO) classification vows to offer pathologists, oncologists and geneticists worldwide a system of classification for human neoplasms based on histopathological and genetic features. Standardization of nomenclature and agreed-upon criteria for definition of the various types of cancer are felt to be a prerequisite for progress in clinical oncology, multicentre therapy trials and comparative studies in different countries. In fact, the WHO effort represents the first worldwide comprehensive consensus classification of the haematological malignancies. Consensus was reached among a subgroup of investigators, carefully selected for their experience and contributions to existing classifications. In the present climate of daily new discoveries that yield a constant stream of fascinating insights into the biology of leukaemias and lymphomas and, above all, resulting in an explosion of potential therapeutic targets, the WHO system has taken the stand of compiling established classification approaches and providing order to known facts. This furnishes an essential skeleton upon which to build in the future. The WHO committee decided that sorting neoplasms according to prognosis was neither practical nor necessary and could be misleading. While justifiable at the present time, it is important to realize that the classifications of the haematological malignancies are a moving target and that the trend is to move away from currently accepted gold standards, such as morphological evaluations, in favour of genetic characterizations, especially those with therapeutic relevance. The goal of this chapter is to fill in some gaps that, as per the author's opinion, exist in the WHO classification, predominantly, where it concerns the role of immunophenotyping as a complementary discipline for genotyping through its potential to generate surrogate marker profiles for molecular lesions. By introducing some state-of-the-art classification modalities, some of which are still awaiting confirmation, this chapter also aims to spark excitement and provide a glimpse at the future.