Heterogeneity in expression of human leukocyte antigens and melanoma-associated antigens in advanced melanoma

The study of tumor immunology has led to many innovative therapeutic strategies for the treatment of melanoma. The strategies are primarily dependent on melanoma-associated antigen peptide vaccination or T-cell-based therapy. These immunotherapies are totally reliant on proper copresentation of human leukocyte antigen class I molecules in sufficient quantity and the presence and availability of melanoma-associated antigenic peptides. Altered expression of either HLA class I molecules or melanoma antigens is known to occur. These defects lead to altered manufacture and copresentation of HLA class I molecules with melanoma-associated antigens to T-cells. Defects in any one combination can lead to loss of recognition of melanoma cells and their subsequent destruction by cytotoxic T-lymphocytes. Thus, these immunotherapy strategies can be thwarted by defects or heterogeneity of expression of human leukocyte antigen class I or of melanoma-associated antigens.     

A 23Na NMR study of the effect of D(+) and L(-) arabitol on NaDNA in aqueous solution.

The 23Na NMR quadrupolar relaxation in NaDNA aqueous solutions has been investigated in the presence of D(+) and L(-) arabitol. Quite different results were produced by the enantiomers, i.e. the addition of D(+) arabitol produced a small increase of the 23Na NMR relaxation rates, while in the presence of L(-) arabitol a significant decrease was observed. These findings were analysed and discussed in terms of an effective interaction of L(-) arabitol with DNA.     

The role of thallium-201 and pentavalent dimercaptosuccinic acid for staging cartilaginous tumours

INTRODUCTION: Heterogeneity of cartilage tumours may confound accurate diagnosis and grading resulting in under and over treatment. Improved preoperative assessment of malignancy and grade would be invaluable for developing a rational plan for treatment. We examined correlations between nuclear tracer avidity and malignancy grade in cartilage tumours. METHODS: Between 1996 and 2000, 92 consecutive patients with cartilaginous tumours (50 benign, 42 non-metastatic malignant) underwent nuclear scanning. Thallium-201 (TL-201) and pentavalent dimercaptosuccinic acid (DMSAV) were used as nuclear isotopes. Scanning with these agents was performed on separate days 48 hours apart. Static and SPECT images were obtained at 30 m and 4 h after injection of nuclear tracer. Pathology review was undertaken blinded to the results of the nuclear scans and correlations between histologic results and trace uptake at 4 hours examined. RESULTS: 25 patients with negative DMSAV had benign tumours. 15/17 tumours with positive TL-201 had malignant tumours. 11/13 patients with both positive DMSAV and TL-201 scans had intermediate or high grade tumours and 4 of these developed metastases. We have developed an algorithm for the management of patients with tumours that aims to avoid over treatment of low grade tumours and under treatment of high grade tumours. CONCLUSION: Functional nuclear scanning with TL-201 and DMSAV complements other imaging modalities in the management of cartilaginous tumours.     

HLA class I antigen downregulation in human cancers: T-cell immunotherapy revives an old story

Human leukocyte antigen (HLA) class I molecule downregulation occurs frequently in many cancers, and this abnormality might adversely affect the clinical course of cancer and the outcome of T-cell-based immunotherapy. Mutations in the HLA class I genes themselves, abnormalities in their regulation and/or defects in HLA class I-dependent antigen processing can underlie HLA class I downregulation. These mutations modulate the susceptibility of tumor cells to in vitro lysis by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Immune selection of CTL- and NK-cell-resistant tumor cells might explain the rapid progression and poor prognosis of cancers that exhibit HLA class I downregulation. These findings provide compelling evidence that HLA class I downregulation represents a significant challenge for the successful application of T-cell-based immunotherapy of cancer.     

Autophagy and genomic integrity

DNA lesions, constantly produced by endogenous and exogenous sources, activate the DNA damage response (DDR), which involves detection, signaling and repair of the damage. Autophagy, a lysosome-dependent degradation pathway that is activated by stressful situations such as starvation and oxidative stress, regulates cell fate after DNA damage and also has a pivotal role in the maintenance of nuclear and mitochondrial genomic integrity. Here, we review important evidence regarding the role played by autophagy in preventing genomic instability and tumorigenesis, as well as in micronuclei degradation. Several pathways governing autophagy activation after DNA injury and the influence of autophagy upon the processing of genomic lesions are also discussed herein. In this line, the mechanisms by which several proteins participate in both DDR and autophagy, and the importance of this crosstalk in cancer and neurodegeneration will be presented in an integrated fashion. At last, we present a hypothetical model of the role played by autophagy in dictating cell fate after genotoxic stress.     

A human memory T cell subset with stem cell-like properties

Immunological memory is thought to depend on a stem cell-like, self-renewing population of lymphocytes capable of differentiating into effector cells in response to antigen re-exposure. Here we describe a long-lived human memory T cell population that has an enhanced capacity for self-renewal and a multipotent ability to derive central memory, effector memory and effector T cells. These cells, specific to multiple viral and self-tumor antigens, were found within a CD45RO(-), CCR7(+), CD45RA(+), CD62L(+), CD27(+), CD28(+) and IL-7Rα(+) T cell compartment characteristic of naive T cells. However, they expressed large amounts of CD95, IL-2Rβ, CXCR3, and LFA-1, and showed numerous functional attributes distinctive of memory cells. Compared with known memory populations, these lymphocytes had increased proliferative capacity and more efficiently reconstituted immunodeficient hosts, and they mediated superior antitumor responses in a humanized mouse model. The identification of a human stem cell-like memory T cell population is of direct relevance to the design of vaccines and T cell therapies.     

Impaired response to influenza vaccine associated with persistent memory B cell depletion in non-Hodgkin's lymphoma patients treated with rituximab-containing regimens

Influenza vaccination is generally recommended for non-Hodgkin's lymphoma (NHL) patients, but no data are available about the activity of this vaccine after treatment with rituximab-containing regimens. We evaluated the humoral response to the trivalent seasonal influenza vaccine in a group of NHL patients in complete remission for ≥6 mo (median, 29 mo) after treatment with rituximab-containing regimens (n = 31) compared with age-matched healthy subjects (n = 34). B cell populations and incidence of influenza-like illness were also evaluated. For each viral strain, the response was significantly lower in patients compared with controls and was particularly poor in patients treated with fludarabine-based regimens. In the patient group, the response to vaccination did not fulfill the immunogenic criteria based on the European Committee for Medicinal Products for Human Use requirements. Among the patients, CD27(+) memory B cells were significantly reduced, and their reduction correlated with serum IgM levels and vaccine response. Episodes of influenza-like illness were recorded only in patients. These results showed that NHL patients treated with rituximab-containing regimens have persisting perturbations of B cell compartments and Ig synthesis and may be at particular risk for infection, even in long-standing complete remission.     

International Meeting “Immunotherapy of Cancer: Challenges and Needs”

The main aims of the international meeting “Immunotherapy of Cancer: Challenges and Needs” were to review the state of the art of cancer immunotherapy and to identify critical issues which deserve special attention for promoting progress of research in this field, with a particular focus on the perspectives of clinical research. Novel concepts and strategies for identifying, monitoring and predicting effective responses to cancer immunotherapy protocols were presented, focused on the use of adjuvants (CpG oligonucleotides) or cytokines (IFN-alpha) to enhance the efficacy of cancer vaccines. Moreover, the possible advantages of using different types of dendritic cells (for active immunization strategies) or T cells (for adoptive immunotherapy protocols) were debated. A consensus was achieved on the need for enhancing the efficacy of cancer vaccines or adoptive cell immunotherapy by combining these strategies with other anti-cancer treatments, including chemotherapy. Finally, initiatives for promoting clinical research by establishing a strategic cooperation in the field of cancer immunotherapy based on the active participation of all the relevant actors, including public institutions responsible of Public Health, National Cancer Institutes, industry, representatives of regulatory bodies, and patients’ organizations were proposed.