Vaccine therapy and chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia: the role of T cells in a B cell disease

Chronic lymphocytic leukaemia (CLL) has long been thought to be an immunosuppressive disease and abnormalities in T-cell subset distribution and function have been observed in many studies. However, the role of T cells (if any) in disease progression remains unclear and has not been directly studied. This has changed with the advent of new therapies, such as chimeric antigen receptor-T cells, which actively use retargeted patient-derived T cells as "living drugs" for CLL. However complete responses are relatively low (~26%) and recent studies have suggested the differentiation status of patient T cells before therapy may influence efficacy. Non-chemotherapeutic drugs, such as idelalisib and ibrutinib, also have an impact on T cell populations in CLL patients. This review will highlight what is known about T cells in CLL during disease progression and after treatment, and discuss the prospects of using T cells as predictive biomarkers for immune status and response to therapy.

Autoimmune cytopenias in chronic lymphocytic leukemia

The clinical course of chronic lymphocytic leukemia (CLL) may be complicated at any time by autoimmune phenomena.The most common ones are hematologic disorders, such as autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). Pure red cell aplasia (PRCA) and autoimmune agranulocytosis (AG) are, indeed, more rarely seen. However, they are probably underestimated due to the possible misleading presence of cytopenias secondary to leukemic bone marrow involvement or to chemotherapy cytotoxicity. The source of autoantibodies is still uncertain, despite the most convincing data are in favor of the involvement of resting normal B-cells. In general, excluding the specific treatment of underlying CLL, the managementof these complications is not different from that of idiopathic autoimmune cytopenias or of those associated to other causes. Among different therapeutic approaches, monoclonal antibody rituximab, given alone or in combination, has shown to be very effective.

Maturation of morphology, phenotype and functions of murine bone marrow-derived dendritic cells (DCs) induced by polysaccharide Kureha (PSK)

The aim of this work was to evaluate the influence of protein-bound polysaccharide Kureha(PSK) on murine dendritic cells (DCs). These impacts of PSK on DCs from bone marrow derived DCs(BMDCs) were assessed with inverted phase contrast microscope, conventional scanning electron microscopy (SEM), transmission electron microscopy (TEM) for morphology, fluorescence activated cell sorting (FACS) analysis, cytochemistry assay for key surface molecules, FITC-dextran for phagocytosis, bio-assay and enzyme linked immunosorbent assay (ELISA) for cytokine production. We found that under the influence of PSK, immature DCs changed into mature DCs with decrease of antigens up-taking, simultaneously high expression of key surface molecules of the MHC classII,CD40, CD80, CD86 and CD83 as well as more production of IL-12p70 and tumor necrosis factor α (TNF-α). These data indicate that PSK could markedly promote maturation of DCs and this adjuvant-like activity may have potential therapeutic value in vaccine preparation.

Study of fibromodulin gene expression in B-cell chronic lymphocytic leukemia

BACKGROUND AND OBJECTIVES

It has become evident that fibromodulin and other members of the proteoglycan family are not only involved in collagen fibrillogenesis and cell adhesion but they also contribute to modulation of cytokine activity, suppression of tumor growth, and prevention of apoptosis. Fibromodulin has been characterized as one of the tumor associated antigens (TAA) in B cell chronic lymphocytic leukemia (B-CLL) with the potential to elicit specific antitumor response and it is considered as good candidate for immunotherapy.

AIM OF WORK

to study the expression of fibromodulin at the gene level of B-cell chronic lymphocytic leukemia patients, in comparison to normal controls and to asses its role in the pathophysiology of CLL.

PATIENTS AND METHODS

Fibromodulin gene expression was tested by one step reverse transcription-polymerase chain reaction (RT-PCR) in peripheral blood mononuclear cells of 30 patients with B-CLL as well as in 20 age and sex matched healthy volunteers.

RESULTS

In this study, fibromodulin gene was expressed in 46.7% of patients with B-CLL which was significantly different from the control age and sex matched healthy volunteers in which none of them showed peripheral blood mononuclear cells positivity for fibromodulin gene expression (0%) (p-value =0.006). We also found significant associations between higher fibomodulin gene expression and some risk factors in the studied CLL cases such as hepatomegaly, lower haemoglobin level, lower RBCs count, lower platelet count and borderline significant associations with other risk factors as lymphadenopathy and splenomegaly.

CONCLUSION

Our results suggest that fibromodulin can be used as a target for therapeutic intervention and it may play a role in the pathophysiology of CLL.

Lenalidomide treatment promotes CD154 expression on CLL cells and enhances production of antibodies by normal B cells through a PI3-kinase-dependent pathway

Chronic lymphocytic leukemia (CLL) involves a profound humoral immune defect and tumor-specific humoral tolerance that directly contribute to disease morbidity and mortality. CD154 gene therapy can reverse this immune defect, but attempts to do this pharmacologically have been unsuccessful. The immune-modulatory agent lenalidomide shows clinical activity in CLL, but its mechanism is poorly understood. Here, we demonstrate that lenalidomide induces expression of functional CD154 antigen on CLL cells both in vitro and in vivo. This occurs via enhanced CD154 transcription mediated by a Nuclear Factor of Activated T cells c1 (NFATc1)/Nuclear Factor-kappaB (NF-kappaB) complex and also through phosphoinositide-3 (PI3)-kinase pathway-dependent stabilization of CD154 mRNA. Importantly, CD154-positive CLL cells up-regulate BID, DR5, and p73, become sensitized to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis, and promote costimulatory activation of normal B cells to produce antibodies. In CLL patients receiving lenalidomide, similar evidence of CD154 activation is observed including BID, DR5, and p73 induction and also development of anti-ROR1 tumor-directed antibodies. Our data demonstrate that lenalidomide promotes CD154 expression on CLL cells with subsequent activation phenotype, and may therefore reverse the humoral immune defect observed in this disease. This study is registered at http://clinicaltrials.gov as NCT00466895.