Dendritic-cell tumor vaccines

Most cancers remain incurable. Introduction of novel therapeutic methods, including new cytostatic regimens and targeted therapies, such as monoclonal antibodies and tyrosine kinase inhibitors, have increased remission rates as well as improved patient survival, but the ability to cure many cancer patients remains elusive. It is thus necessary to further develop alternative strategies to improve patient prognosis. The majority of patients who respond to induction therapy inevitably relapse, mainly because of the proliferation of residual malignant cells that have escaped control by induction chemotherapy. Therefore the eradication of minimal residual disease may be crucial to prevent a relapse and achieve a long-term remission. It seems that an advantageous treatment option may be cellular immunotherapy with dendritic-cell vaccines which might induce long-term specific anticancer responses with immune memory cells, which could contribute to effective and lasting elimination of malignant cells.

Expression of RHAMM/CD168 and other tumor-associated antigens in patients with B-cell chronic lymphocytic leukemia

Antigen targeted immunotherapies might represent a novel treatment for B-cell chronic lymphocytic leukemia (B-CLL). We screened the mRNA expression of tumor-associated antigens (TAAs) from the literature (fibromodulin, survivin, OFA-iLRP, BAGE, G250, MAGE1, PRAME, proteinase, syntaxin, hTERT, WT-1) and TAAs defined previously by serological analysis of cDNA expression libraries from leukemic cells (PINCH, HSJ2, MAZ, MPP11, RHAMM/CD168, NY-Ren60). Peripheral blood mononuclear cells from 43 B-CLL patients and 20 healthy volunteers (HVs) were examined by conventional and quantitative RT-PCR. mRNA of RHAMM/CD168, fibromodulin, syntaxin and NY-Ren60 was expressed in 55-90%, and mRNA of HSJ2, MAZ and OFAiLRP was expressed in 90-100% of the patients. No expression of WT-1, hTERT, BAGE, G250, MAGE1 or survivin was observed. Low (2-20%) expression frequencies of MPP11, PINCH, PRAME and proteinase were detected. RHAMM/CD168, fibromodulin, PRAME and MPP11 showed expression in B-CLL patients, but not in HVs. Because of the exquisite tissue expression of RHAMM/CD168 and its high expression frequency in CLL patients, mixed lymphocyte peptide culture (MLPC), enzyme-linked immunosorbent spot (ELISPOT) and flow cytometry were performed for antigen specific T-cells. In MLPC, RHAMM specific responses by CD8+HLA-A2/R3tetramer+CCR7-CD45RAhigh effector T-cells were detected. RHAMM/CD168 might be a possible target for future immunotherapies in both ZAP-70(+) and ZAP-70(-) B-CLL patients.

The clinical significance of ZAP-70 and CD38 expression in B-cell chronic lymphocytic leukaemia

BACKGROUND

B-cell chronic lymphocytic leukaemia (B-CLL) is a disease with a highly variable clinical course; some patients never need treatment, while others require intensive treatment early after diagnosis. Recently, some new prognostic factors, such as IgVH mutational status, ZAP-70 and the expression of CD38 in leukaemic cells were introduced to identify attenuated versus progressive types of CLL bearing the potential to facilitate risk-adapted treatment strategies.

PATIENTS AND METHODS

To evaluate the clinical value of ZAP-70 and CD38 as predictors of disease progression we assessed the expression of these markers by the flow cytometry method in 156 B-CLL patients.

RESULTS AND CONCLUSIONS

Both ZAP-70 and CD38 expression were shown to predict the clinical course of the disease, while ZAP-70 expression appeared to be more predictive than CD38 expression and more relevant in defining the cases of B-CLL responsive or refractory to first line chemotherapy. A simultaneous evaluation of ZAP-70 and CD38 expression allowed distinguishing the patients groups with the most favourable prognosis as well as those with the worst. Taken together we recommend assessing both ZAP-70 and CD38 protein expression for the definition of prognostic subgroups in patients with B-CLL.

Allogeneic dendritic cells pulsed with tumor lysates or apoptotic bodies as immunotherapy for patients with early-stage B-cell chronic lymphocytic leukemia

Recently, immunotherapies with allogeneic dendritic cells (DCs) pulsed with tumor antigens to generate specific T-cell responses have been tested in clinical trials for patients with solid tumors. This is the first report on a clinical vaccination study with DCs for patients with B-cell chronic lymphocytic leukemia (B-CLL). The potential of allogeneic DCs pulsed ex vivo with tumor cell lysates or apoptotic bodies to stimulate antitumor immunity in patients with B-CLL in early stages was evaluated. Monocyte-derived DCs were obtained from unrelated healthy donors. Nine patients (clinical stage 0 and 1 according to Rai) were vaccinated five times with a mean number of 32 x 10(6) stimulated DCs administered intradermally once every 2-3 weeks. No signs of autoimmunity were detected, and only mild local skin reactions were noted. During the treatment period, we observed a decrease of peripheral blood leukocytes and CD19+/CD5+ leukemic cells. In one patient, a significant increase of specific cytotoxic T lymphocytes against RHAMM/CD168, a recently characterized leukemia-associated antigen, could be detected after DC vaccination. Taken together, the study demonstrated that DC vaccination in CLL patients is feasible and safe. Immunological and to some extent hematological responses could be noted, justifying further investigation on this immuno-therapeutical approach.

An evaluation of factors predicting long-term response to thalidomide in 234 patients with relapsed or resistant multiple myeloma

The aim of this study was to assess the prognostic value of pretreatment clinical and laboratory parameters in refractory or relapsed multiple myeloma (MM) patients who have a long-term response to thalidomide (THAL), lasting at least 18 months. The study was carried out on 234 patients who received THAL for relapsed/refractory myeloma. Out of the 234 patients, 129 patients (55.1%) responded to THAL with a mean response duration of 11.9 months (ranging from 1 to 48) and an overall survival rate of 20.3 months (ranging 1–55 months). In 64 patients (27.4% of the whole group), the response to THAL lasted ⩾18 months with a mean response lasting 24 months. Statistical analysis of the group of nonresponders and patients with long-term response to THAL showed a significantly higher serum albumin level (P=0.0003) and haemoglobin level (P=0.05), as well as a lower β2 microglobulin (β2M) (P=0.022), LDH (P=0.045) serum level in patients with long-term response. In this study, the LDH and serum albumin level were predictors for response to THAL therapy. The β2M serum level was not a predictor for response to THAL. The albumin serum level was the best parameter distinguishing the group of patients with long-term response to THAL from the entire responding group (P=0.02).

Effect of granulocyte-macrophage colony-stimulating growth factor on interferon and tumor necrosis factor production in whole blood cell cultures of patients with acute myelogenous leukemia

The effect of recombinat human granulocyte-macrophage colony-stimulating growth factor (rHuGM-CSF) treatment on in vitro interferon (IFN) and tumor necrosis factor (TNF) production in peripheral blood cells of 46 patients with acute myelogenous leukemia (AML) was examined. GM-CSF significantly enhanced virus-induced IFN-alpha production in blood cells (containing 68% of blasts) of 28 patients with M4-M5 AML according to the French-American-British (FAB) classification and also phytohemagglutinin (PHA)-induced IFN-gamma production in blood cells (containing 70% of blasts) of 18 patients with AML MO-M3 type. In control blood cells (25 healthy persons) GM-CSF enhanced PHA-induced IFN-gamma but did not influence IFN-alpha production. In the presence of GM-CSF, TNF-alpha titers induced with lipopolysaccharide were also higher in control blood cells but not in cells of patients with M0-M3 or M4-M5 type of AML. The significance of GM-CSF-enhanced IFN-alpha and IFN-gamma production in antimicrobial and anti-leukemic immune reactions which can develop during GM-CSF therapy is discussed.

Effect of granulocyte colony stimulating factor treatment on ex vivo cytokine production by blood cells of patients after chemotherapy or radiotherapy

We explored ex vivo alterations in the cytokine release of stimulated blood cells taken from 8 patients with hematological malignancies who, after chemotherapy or radiotherapy developed leukopenia, and were treated for 3-7 days subcutaneously with granulocyte colony stimulating factor (G-CSF), daily, dose of 5 microg/kg of body weight. Blood was also taken from 8 healthy controls not treated with G-CSF and from patients before and 24 h after last dose of G-CSF and ex vivo treated with interferon (IFN) inducers: Newcastle disease virus (NDV), phytohemagglutinin (PHA), concanavalin A (Con A) and with tumor necrosis factor (TNF) inducer--lipopolysaccharide (LPS). Blood cells of patients before G-CSF treatment exhibited ex vivo a low ability to produce IFN-gamma in comparison to controls. After G-CSF therapy a significant increase in IFN-alpha production ability was detected. We conclude that G-CSF treatment for 3-7 days does not only increase the number of white blood cells (WBC) and neutrophilic granulocytes but also modify the host response of patients with hematological malignancies to microbial infections.

Cytokine production in whole blood cell cultures of patients with B-lineage acute lymphoblastic leukemia. The influence of granulocyte-macrophage colony-stimulating factor

We investigated the levels of 6 different cytokines in the sera of 10 newly diagnosed patients with B cell lineage acute lymphoblastic leukemia (ALL) and detected a significant increase in IL-6 and IFN-alpha serum levels in comparison to that of healthy controls. Whole blood cell cultures of 10 ALL patients and 20 control individuals were induced with classical cytokine inducers, such as virus, PHA and LPS, and their ability to produce 9 different cytokines was compared. Blood cells of ALL patients produced significantly less IL-1alpha, IL-1beta, IL-10 and TNF-alpha than control cells and not significanly lower levels of IL-6, but comparable with control levels of IL-2, IL-4. rHuGM-CSF added to cell cultures 24 h before induction significantly enhanced the production of IL-1alpha, IL-1beta and TNF-alpha in controls, but only IL-1alpha and IL-1beta in the blood cell cultures of patients with ALL. GM-CSF did not significantly influence the production of IFN-alpha, IFN-gamma, IL-2, IL-4 and IL-10 in the control cells and the cells of ALL patients. The patients examined differed not only in the expression of CD10 and CD34 antigens on blast cells, but also in the reaction to GM-CSF treatment, which was found as very high standard deviation values. We suppose that these differences can partially explain the different effects of GM-CSF when used to ameliorate neutropenia of ALL patients after chemotherapy and to reduce the incidence of microbial infections.

Interferon gamma as immunomodulator in a patient with multiple myeloma

We describe here a patient with multiple myeloma, who, while in remission after chemotherapy, received 100 micrograms of rIFN-gamma (Imukin, Boehringer, Ingelheim) subcutaneously 3 times a week for 4 weeks as supportive therapy before autologous peripheral blood stem cell transplantation (PBSCT). The patient was monitored for serum IFN, TNF, IL-2 activities and for the ability of peripheral blood leukocytes (PBL) to produce IFN-alpha/beta, IFN-gamma, IL-2 and TNF-alpha after in vitro induction. Changes in the percent of plasma cells in the bone marrow, in the total and differential white blood cell counts, in T cell subsets and NK cells were also monitored. IFN-gamma yielded no clinical antitumor activity. The number of bone marrow plasma cells increased, however, the percentage of blood and bone marrow NK cells and the CD4/CD8 T cell subset ratio decreased. Monitoring the cytokine production ability of PBL during IFN-gamma therapy revealed an increase in IL-2, IFN-gamma and TNF-alpha titers produced upon in vitro induction after 2 weeks of treatment (6 injections of rIFN-gamma). However, after 9 injections there was a significant decrease in IFN-gamma and IL-2 production in the PBL, and at the end of therapy (12 injections) the decrease not only in IL-2 and in IFN-gamma but also in IFN-alpha production was observed. In contrast to these changes, TNF production was strongly enhanced and reached the level observed before the therapy. These data suggest that the schedule of IFN-gamma therapy in multiple myeloma should perhaps be adapted to become more effective, taking advantage from the immunomodulating activity of IFN-gamma.

[Clinical and immunologic characteristics of CD 34 positive acute myeloid leukemia]

Expression of antigen CD 34+ on acute myeloid leukemia is admittedly regarded as a negative prognostic factor, however some authors deny it. The aim of our studies was clinical, morphological and immunological analysis of AML CD 34+. In the group of 39 patients with de novo AML there was 46% of AML CD 34+ (18 cases--14 women and 4 men aged 18 to 80 years--mean 52.5). The diagnosis was made according to FAB criteria and immunophenotype estimation by immunocytochemical method APAAP. The following types of AML were found: MO-4 cases, M1-1, M2-4, M4-8, M5-1. Analysis of clinical features of AML CD 34+ did not show any characteristic features either in peripheral blood smear, or bone marrow smear. Most patients were treated according to the EPR+Ara-C scheme, with addition of VP-16 in M4 types, one patient--IDA+VP-16 + Ara-C, three elderly patients were treated with low doses of Ara-c, one patient refused cytostatic treatment. Three patients achieved complete remission (17.6%), three achieved partial remission (17.6%), four died during the phase of aplasia and seven others (41.2%) were completely resistant for chemotherapy. These results confirm association between CD34 expression and drug resistance.