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Although anti-CD20 monoclonal antibodies (mAbs) show promise for the treatment of chronic lymphocytic leukemia (CLL), the success of the anti-CD20 mAb rituximab in CLL treatment has been limited. Novel anti-CD20 mAbs with more potent cytotoxic activity have recently been engineered, but so far most have only been tested in vitro with natural killer (NK) cells from healthy donors. Because it is still unclear whether these optimized cytotoxic mAbs will improve NK-cell killing of tumor cells in CLL patients, we characterized the relevant phenotypic and functional features of NK cells from CLL patients in detail. Expression of inhibitory and activating NK-cell receptors and of Fc gamma receptor IIIA (FcγRIIIA) is well preserved in CD16+CD56dim cytotoxic NK cells from these patients, independently of disease progression. These cells are fully functional following cytokine stimulation. In addition, the FcγRIIIA-optimized LFB-R603 anti-CD20 mAb mediates 100 times greater antibody-dependent cell-mediated cytotoxicity by NK cells from CLL patients and healthy donors than rituximab. Enhanced degranulation against autologous B-CLL cells is observed at lower concentrations of LFB-R603 than rituximab, regardless of CLL prognostic factors. These findings strongly justify further clinical development of anti-CD20 mAbs optimized for FcγR engagement in CLL patients. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukemia (CLL)-B-cells are quiescent differentiated cells that produce interleukin (IL)-10 and accumulate due to resistance to apoptosis. The mechanisms underlying such resistance are poorly understood. Herein we show that all CLL B-cells tested (30/30) display high mRNA and protein expression of the tumor suppressor Mda-7/IL-24, an IL-10 family member, in comparison to normal B cells. A downstream Mda-7 signaling target, p38 mitogen-activated protein kinase (MAPK) was highly phosphorylated in all CLL cells but not in normal B-cells. Mda-7 expression and p38 MAPK phosphorylation diminished in culture and the latter could be reinduced by recombinant (r)-IL-24 or LPS and Mda-7 transfection. Mda-7/IL-24 siRNA specifically inhibited p38 MAPK phosphorylation in CLL without affecting p38 MAPK, bcl2, or Lyn expression, further demonstrating the direct role of Mda-7/IL-24 in p38 MAPK activation. Both pharmacological inhibition of p38 MAPK and Mda-7 silencing augmented spontaneous apoptosis by three-fold in CLL cells cultured in autologous serum, which was reversed by LPS and r-IL-24. We established the role of p38 MAPK in CLL cell survival and demonstrated a paradoxical effect, whereby Mda-7 and IL-24, inducers of apoptosis in diverse cancer cells, promote the survival of CLL B-cells through p38 MAPK activation.Leukemia (2006) 20, 498–504. doi:10.1038/sj.leu.2404073; published online 12 January 2006 [ABSTRACT FROM AUTHOR]

Our recent work has shown that theophylline which inhibits intracellular cyclic adenosine monophosphate (cAMP) degradation is able to kill chronic lymphocytic leukemia (CLL) cells in vitro and synergizes in vitro and in vivo with chlorambucil. In order to test the hypothesis that theophylline works through an indirect increase in cAMP, we have investigated the role of several molecules on B-CLL cells from 20 patients. Direct cAMP inducers such as dibutyryl-cAMP (db-cAMP), prostaglandin-E2 (PGE2) and forskolin induced moderate apoptosis but extremely high levels of intracellular cAMP. By contrast theophylline was highly apoptotic but did not synergize with cAMP inducers. Apoptosis was completely reversed by a cAMP antagonist when induced by PGE2 or forskolin, but was only partially antagonized when induced by theophylline. Since CD38+ CLL cells are more sensitive to apoptosis and since CD38 is enhanced by cAMP inducing agents its expression was investigated. In our hands CD38 was not induced by the above pharmacological compounds. Exogenous IL-10 has been shown to induce CLL cell death; however, apoptosis following treatment with theophylline or cAMP inducers could not be ascribed to endogenous production of IL-10. This ruled out the involvement of cytokines or of an activation or differentiation process in apoptosis. Altogether our data show that an increase in intracellular cAMP mediates apoptosis in vitro but accounts only partly for theophylline-mediated apoptosis. [ABSTRACT FROM AUTHOR]

Given the generally poor outcome of advanced B cell chronic lymphocytic leukemia, experimental approaches are warranted, especially for younger patients in whom classical treatments have failed. We therefore conducted a prospective single-center study, using polychemotherapy (ESHAP) to prepare patients for hematopoietic stem cell collection and autologous stem cell transplantation as consolidation therapy. Twenty patients entered the study. An adequate response to ESHAP was obtained in 13 patients, and sufficient stem cells for grafting were obtained in eight of the 12 patients who underwent the collection procedure. Six of these grafted patients are alive in complete clinical remission a median of 30 months after transplantation. It should be noted that we were only able to graft 40% of the patients enrolled in this study, either because a new remission could not be obtained or because not enough hematopoietic stem cells could be collected. This argues for stem cell collection as soon as a first remission is obtained, even if the autograft is done later in the course of the disease. [ABSTRACT FROM AUTHOR]

In this report we reviewed the recent data regarding the involvement of apoptosis or progammed cell death in hematological diseases. We summarized new features of apoptosis including high molecular weight DNA fragmentation and programmed cell death of enucleated cells. We described the recent contributions about the three oncogenes bcl-2, p53 and c-myc. New inducers and inhibitors of apoptosis have been reported, particularly the role of stromal environment, thrombopoietin, erythropoïetin and flt-3 ligand has been mentioned. Apoptosis has been studied in red cell pathology: polycythemia, thalassemia and deficiency in folates, vitamin B12, iron and G6PD. Recently, the involvement of programmed cell death has been documented in bone marrow failure and myelodysplasia. In Acute Leukemia, the therapeutic action of numerous drugs has been proven by their in vitro apoptotic effect. The resistance of malignant cells to apoptosis, in Chronic Myeloid Leukemia, due to bcr-abl oncogene, has been partially explained by conformational changes in p53 expression and is reversed by retinoic acid. Numerous reports in Chronic Lymphocytic Leukemia have documented the major role of apoptosis in this disease, especially in therapeutic efficacy of Chlorambucil, Fludarabine and Methylxanthine derivatives. At least, in Myeloma, it has been shown that apoptosis is induced by dexamethasone and HMBA, and inhibited by interleukine 6 that prevents activation of SAP Kinases. [ABSTRACT FROM AUTHOR]

Presents a study on the association of human herpesvirus 8 or Kaposi's sarcoma-associated herpesvirus infection to the plasma-cell lineage. Similarity of the gene expression profile of primary effusion lymphoma to that of transformed plasma cells; Details on the pathogenesis of tumoral lymphoproliferations; Occurrence of multiple infection events in a single tumor cell.

INTRODUCTION:: Among patients with indolent form of B-cell chronic lymphocytic leukemia, some of them will progress into more advanced stages. To better define this subpopulation of patients, we attempted to define some parameters capable of predicting a pejorative clinical outcome. MATERIALS AND METHODS:: Eighty-eight previously untreated patients with B-cell chronic lymphocytic leukemia in Binet stage A were analysed to study the prognostic value of simple serological variables: soluble CD23 (sCD23), β2 microglobulin (β2m), lactate-dehydrogenase activities and albumin level. Results were compared to other conventional clinical and biological parameters by univariate and multivariate statistical analysis. RESULTS:: Our data show that: (1) among those studied, sCD23 >50 u/ml was the only serological significant parameter clearly correlated with disease progression and (2) stage A′′ patients (hemoglobin level between 100 and 120 g/l and/or lymphocytosis >30.109/l), axillary lymph nodes and hypogammaglobulinemia were found to be other variables associated with a pejorative outcome. These four variables enabled the establishment of a scoring system, capable of predicting disease progression since 66% of the patients with a score 2 are going to evolve into advanced stages vs 12% with a score <2. Furthermore, the time to progression is shortened when the score is increasing. CONCLUSION:: Our findings show the prognostic relevance of a scoring system including sCD23 level. This score could be taken into account in the treatment strategy of B-cell chronic lymphocytic leukemia.The Hematology Journal (2000) 1, 301–306 [ABSTRACT FROM AUTHOR]