CD1d Expression Is Higher In Chronic Lymphocytic Leukemia Patients With Unfavorable Prognosis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5278-5278
Author(s):  
Agnieszka Bojarska-Junak ◽  
Iwona Hus ◽  
Anna Dmoszynska ◽  
Jacek Rolinski
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Disease Progression ◽  
Conflicts Of Interest ◽  
Staining Intensity ◽  
Lymphocytic Leukemia ◽  
Disease Stage ◽  
Inkt Cells ◽  
Cd38 Expression

Abstract Chronic lymphocytic leukemia (CLL) is characterized by a very heterogeneous clinical course, which is slow and indolent in most of the patients, however some patient experience rapid disease progression and anticancer therapy is required shortly after the diagnosis. Many issues in CLL development and progression are still unclear. The functional consequences of CD1d expression on tumour cells are not well understood. However, increasing evidence suggests that they may affect iNKT cells.The role of CD1d expression in CLL immunopathogenesis remains undefined. In this study, we investigated the potential role of CD1d in CLL by analyzing the level of CD1d expression on leukemic B cells in peripheral blood of120 patients and assessed its correlation with prognostic markers such as ZAP-70 and CD38 expression, Rai stages and unfavourable cytogenetic changes.Measuring CD1d expression by flow cytometry and qRT-PCR, we showed lower CD1d molecule and CD1d mRNA expression in B cells of CLL patients than of healthy controls. The frequency of CD1d+/CD19+ cells, CD1d staining intensity and CD1d transcript levels increased with the disease stage. CD1d expression was positively associated with ZAP-70 and CD38 expressions as well as with unfavourable cytogenetic changes (17p deletion, 11q deletio),. We established the relationship between high CD1d expression and shorter time to treatment and overall survival. The percentage of CD1d+/CD19+cells inversely correlated with the percentage of iNKT cells. iNKT cells ζ-chain expression was downregulated in the high-CD1d group.These results suggest that high CD1d expression is associated with poor prognosis of CLL and might be involved in disease progression. Disclosures: No relevant conflicts of interest to declare.

Different Expression of FcgammaRIIb in Chronic Lymphocytic Leukemia and Human Normal B Lymphocytes

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3134-3134
Author(s):  
Carol Moreno ◽  
Rajendra Damle ◽  
Sonia Jansa ◽  
Gerardo Ferrer ◽  
Pau Abrisqueta ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
B Lymphocytes ◽  
Surface Membrane ◽  
Memory B Cells ◽  
Lymphocytic Leukemia ◽  
Cd38 Expression ◽  
B Cell Subsets

Abstract The Fcgamma receptors (FcγRs) are a family of molecules that modulate immune responses. FcγRIIb is an inhibitory FcγR that bears immunoreceptor tyrosine-based inhibitory motifs which transduce inhibitory signals on coligation with the surface membrane Ig of the B-cell antigen receptor (BCR). The role of FcγRIIb in controlling B cell activation through inhibition of BCR signaling has been extensively studied in animal models. Nevertheless, data on FcγRIIb are scant in human normal and neoplastic B cells, this being due to the lack of a specific antibody for human FcγRIIb. Consequently, there is little information on this receptor in chronic lymphocytic leukemia (CLL). Considering the activated nature of CLL cells and the central role of the BCR in the biology of the disease, studies of FcγRs are warranted. We used a novel specific mAb directly conjugated with Alexa 488 fluorophore that solely reacts with the human FcγRIIb (MacroGenics, Inc.) to investigate the receptors expression on CLL and normal human B cells. The study population included 84 patients with CLL and 24 age- and sex-matched controls. FcγRIIb expression was assessed as the mean fluorescence intensity (MFI) of surface membrane staining. In CLL cells, FcγRIIb was measured on CD19+CD5+ cells in combination with CD38, CD49d or CD69. Normal B cells were immunostained for CD19, CD5, IgD and CD38 expression and B cell subsets: naïve (IgD+CD38−), activated (IgD+CD38+) and memory B cells (IgD−CD38−) were studied for their relative expression of FcγRIIb. FcγRIIb expression was found significantly higher in naïve B cells compared to activated and memory B cells [median MFI: 17420 (11960–21180) vs. 11.140 (7899–16970) and 11.830 (6984–17100); p<0.001]. Significant differences were also observed between CD5− and CD5+ normal B cells. In contrast, FcγRIIb expression was lower in CLL cells than in CD5+ and CD5− normal B lymphocytes [median MFI: 6901(1034–42600), 10180 (5856–14820) and 12120 (7776–16040); p<0.05)]. Interestingly, FcγRIIb expression was variable within individual CLL clones, this being higher in CD38+ and CD49d+ cells than in CD38− and CD49d− cells (p<0.05). Furthermore, the highest density of FcγRIIb was observed on those cells which coexpressed CD38 and CD49d. In contrast, no significant differences were observed between FcγRIIb and the expression of the activation antigen CD69. Although CD69 and CD38 expression was significantly higher on unmutated IGHV cases, no correlation was found between FcγRIIb levels and IGHV mutational status. Similarly, there was no correlation between FcγRIIb and other poor prognostic variables such as ZAP-70 (≥20%), CD38 (≥ 30%) or high risk cytogenetics. Nevertheless, cases with ≥ 30% CD49d+ cells had higher FcγRIIb expression than those with <30% CD49d+ cells (p=0.006). The findings presented in this study suggest a hierarchy of FcγRIIb expression in normal B-cells, CLL cells and their subpopulations: circulating normal CD5− B cells > circulating normal CD5+ B cells > circulating CD5+ CLL B cells. In addition, although FcγRIIb is present on all normal B cell subsets its expression is higher in naïve B cells. Furthermore, in CLL FcγRIIb density is greater in CD38+ and CD49d+ cells within the clone. Although CD49d and FcγRIIb on CLL clones is linked in a direct manner, there is no relationship with FcγRIIb density and IGHV mutations, ZAP-70, CD38 and unfavorable cytogenetic markers. Finally, the relationship between FcγRIIb expression on CLL cells and functional responses to BCR and other receptor-mediated signals deserve further investigation.

CD38 Expression above 20% Predicts Disease Progression in Chronic Lymphocytic Leukemia and Is a Useful Prognostic Marker Where Cytogenetic and Molecular Markers Are Not Available

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4190-4190
Author(s):  
Sina Alipour ◽  
Heather Leitch ◽  
Linda M Vickars ◽  
Lynda M Foltz ◽  
Paul F Galbraith ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Disease Progression ◽  
Lymphocyte Count ◽  
Univariate Analysis ◽  
Prognostic Significance ◽  
Progression Free Survival ◽  
Lymphocytic Leukemia ◽  
Disease Stage ◽  
Free Survival ◽  
Cd38 Expression

Abstract The prognostic significance of CD38 expression and the cut off value has not been fully investigated. As CD38 is readily available test in patients with chronic lymphocytic leukemia (CLL), we investigated its role in prediction of disease progression when a cut off value of 20% is used. Progression free survival (PFS) was defined as the time from diagnosis to first treatment or last follow up. An electronic database search of pts with CLL who presented at St Paul’s Hospital between 1969 and 2007 was performed. Among 465 pts with CLL, 161 pts (35%) had their CD38 expression measured by flow cytometry. CD38 expression and its association with other prognostic factors such as age, Rai stage, lymphocyte count at diagnosis, gender and other immunophenotypic makers were analyzed. Out of 161 pts, positive CD38 expression (>20%) was found in 36 patients (22%). Comparing the baseline characteristics of the CLL pts with CD38+ and negative disease, we found CD38 positivity more common in male pts than in female pts (p=0.03). Also patients with CD38 positive disease tend to present with more advanced stage disease (p=0.056). Progression free survival at 2, 5 and 10y for the CD38+ CLL pts was 89%, 61% and 41% respectively compared with 95%, 81% and 62% for the CD38 negative group (p=0.03). Univariate analysis revealed the following factors as significant or marginally significant for disease progression: CD38+ (p=0.03), male gender (p=0.07), Rai stage (p<0.0001), lymphocyte count above 20 ×109/l at diagnosis (p<0.0001), CD5 expression <10% (p=0.01). On multivariate analysis, only disease stage at diagnosis (p<0.0001) and CD38 expression above 20% (p=0.04) retained significant and were predictive for disease progression. We conclude that CD38 expression above 20% at the time of diagnosis can be prognostically useful and predicts for disease progression and along with Rai staging can provide inexpensive tool to follow and monitor patients with CLL. Table: Characteristics of patients with CLL based on CD38 ≥20% and <20% Parameter CD38 ≥20% (%) CD38<20% (%) p value* *for differences between the groups. Number 36 125 Sex: M/F (ratio) 22/14 (1.6:1) 66/60 (1.1:1) 0.03 Age above 60 y 21 (58) 81 (65) 0.2 Rai stage: 0, 1+2, 3+4 20, 11, 5 (55, 31, 14) 100, 17, 1 (80, 14, 0) 0.056 Lymphocyte count above 20×109/l 9 (25) 23 (18) 0.3 CD5 <10% 6 (16) 29 (23) 0.3 Fig: Progression free survival for patients with CLL based on CD38 expression, cut off level 20%. Fig:. Progression free survival for patients with CLL based on CD38 expression, cut off level 20%.

Association of a novel regulatory polymorphism (−938C>A) in the BCL2 gene promoter with disease progression and survival in chronic lymphocytic leukemia

Blood ◽  
2006 ◽  
Vol 109 (1) ◽  
pp. 290-297 ◽  
Author(s):  
Holger Nückel ◽  
Ulrich H. Frey ◽  
Maja Bau ◽  
Ludger Sellmann ◽  
Jens Stanelle ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Cox Regression ◽  
Gene Promoter ◽  
Lymphocytic Leukemia ◽  
Disease Stage ◽  
Genotype Distribution ◽  
Single Nucleotide ◽  
Regulatory Polymorphism ◽  
Time To First Treatment

Abstract Bcl-2 plays a key role in the regulation of apoptosis. We investigated the role of a novel regulatory single-nucleotide polymorphism (−938C>A) in the inhibitory P2 BCL2 promoter in B-cell chronic lymphocytic leukemia (B-CLL). The −938C allele displayed significantly increased BCL2 promoter activity and binding of nuclear proteins compared with the A allele. Concomitantly, Bcl-2 protein expression in B cells from CLL patients carrying the −938 AA genotype was significantly increased compared with CC genotypes. Genotype distribution between 123 CLL patients (42 AA, 55 AC, 26 CC) and 120 genotyped healthy controls (36 AA, 63 AC, 21 CC) was not significantly different, suggesting that genotypes of this polymorphism do not increase the susceptibility for B-CLL. However, median time from first diagnosis to initiation of chemotherapy and median overall survival were significantly shorter in patients with −938AA genotype (38 and 199 months, respectively) compared with AC/CC genotypes (120 and 321 months, respectively; P = .008 and P = .003, respectively). Multivariable Cox regression identified the BCL2−938AA genotype as an independent prognostic factor for the time to first treatment (hazard ratio [HR] 1.9; P = .034) together with disease stage at diagnosis (HR 2.5; P = .004) and ZAP-70 status (HR 3.0; P = .001). The BCL2−938AA genotype is associated with increased Bcl-2 expression and a novel unfavorable genetic marker in patients with B-CLL.

Chronic Lymphocytic Leukemia (CLL) Cells Require Microenvironmental Stimuli to Resist Apoptosis through Activation of STAT3 Mediated by VEGF.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1069-1069
Author(s):  
Iris Gehrke ◽  
Julian Paesler ◽  
Rajesh Kumar Gandhirajan ◽  
Regina Razavi ◽  
Alexandra Filipovich ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Cell Survival ◽  
Lymphocytic Leukemia ◽  
Vegf Receptor ◽  
Mrna Levels ◽  
Activated State ◽  
Survival Effect

Abstract B-cell chronic lymphocytic leukemia (CLL) is characterized by an accumulation of mature, but incompetent B-cells due to a decrease of apoptosis rather than an increase in proliferation. Vascular endothelial growth factor (VEGF) has been suggested to play an important role in this so called apoptotic block. However, so far little is understood whether VEGF is acting mainly as a microenvironmental stimulus and/or whether CLL cells themselves contribute to the enhanced apoptotic resistance by maintaining an autocrine VEGF loop. Moreover, it is unknown by which mechanisms VEGF prevents apoptosis and whether this can be circumvented by inhibition of VEGF signaling. By quantitative real time PCR we found no significant difference in mRNA VEGF levels in B-cells from CLL patients and healthy donors after isolation from blood. In contrast, ELISA revealed clearly increased levels of secreted VEGF in plasma of CLL patients and in the supernatant under culture conditions compared to healthy individuals. In addition, we found the VEGF receptor 2 (VEGFR2), which is existent in CLL and healthy B-cells, in a phosphorylated, hence activated state, to a significantly higher extent in CLL cells as assessed by intracellular phospho flow cytometry. In conclusion, despite its expression in healthy B-cells VEGF does not seem to be secreted and therefore, no VEGF receptor phosphorylation takes place. Whereas CLL cells exhibit a long life span in vivo, they die rapidly in vitro, suggesting major survival factors being existent in the CLL cells microenvironment. We found levels of secreted VEGF in supernatant decreasing with time in culture, going along with decreasing levels of phosphorylated VEGFR2 and increasing cell death as assessed by Annexin V-FITC/PI staining. This further supports the role of VEGF in CLL cell survival. Coculturing primary CLL cells with the bone marrow stromal derived cell line HS5 dramatically increased VEGF transcription and secretion and improved cell survival. Hence, VEGF expression in CLL cells is not only mediated by autocrine, but also paracrine stimuli involving bone marrow stromal. Knocking down VEGF in HS5 cells and subsequent coculture with CLL cells might prove the major role of VEGF in this survival supporting coculture setting. Besides coculturing also supplement of culture medium with recombinant human VEGF (rhVEGF) increased survival, but to a lesser extent than coculture, indicating a direct cell-cell interaction as advantageous. Furthermore, we found a downregulation of anti apoptotic proteins, such as X-linked inhibitor of apoptosis protein (XIAP), myeloid cell leukemia 1 (MCL1) and BclXL upon VEGF stimulation. Also cyclinD1 was upregulated as seen by immunoblotting. We further tried to discover the underlying mechanism of how VEGF mediates its pro survival effect and found STAT3 to become phosphorylated on tyrosine 705 upon VEGF stimulation. In CLL STAT3 is known to be constitutively phosphorylated on serine 727. This phosphorylation is not sufficient to induce target gene expression though. We could show that Y705 phosphorylation of STAT3 is responsible for upregulation of anti apoptotic BCLXL and cyclinD1. A PCR array detecting mRNA levels of 84 transcription factors in untreated and VEGF stimulated CLL cells shall provide more information about mechanistical details how VEGF mediates it pro survival effect. Since VEGF seems to be a major player in CLL cell survival it might be a suitable target to overcome the apoptotic block. In first experiments we found an induction of apoptosis after neutralization of VEGF or inhibition of the VEGF receptor. This additionally highlights the severe importance of VEGF in the apoptotic block in CLL cells. Therefore, VEGF might serve as an excellent therapeutic target in CLL.

CD72 Expression Patterns in ZAP70 Positive and Negative Chronic Lymphocytic Leukemia: Potential Regulatory Role in BCR Signalling

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4159-4159
Author(s):  
Francisco P. Careta ◽  
Rodrigo A. Panepucci ◽  
Daniel M Matos ◽  
Rodrigo Proto-Siqueira ◽  
Wilson A. Silva-Junior ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Expression Patterns ◽  
Surrogate Marker ◽  
Lymphocytic Leukemia ◽  
Negative Regulator ◽  
Beta Catenin ◽  
Cell Surface Glycoprotein ◽  
Expression Levels

Abstract Introduction: Absence of mutations in IgVH genes or higher number of ZAP70+ cells (as a surrogate marker) in chronic lymphocytic leukemia (CLL) B-cells defines a patient group with a poorer clinical course. These features relate to the role of BCR signalling in the proliferation and survival of CLL B-cells, and establish a link between these markers and the biology of CLL prognostic subgroups. The identification of additional players in this context may help to better understand the molecular basis of this disease and contribute to develop new therapeutic approaches. A search for genes potentially related to BCR signalling, when comparing mutated and unmutated CLL cases using serial analysis of gene expression, revealed a 4-fold increase of CD72 tags in unmutated samples, a specific B cell surface glycoprotein known to transmit both positive and negative signals in BCR signalling. Objective: This finding lead us to explore the potential role of CD72 on BCR signalling in distinct CLL prognostic subgroups, as defined by ZAP70 expression. Methods: Percentage of ZAP70+ and CD72+ cells were evaluated by flow cytometry on gated CD19+CD5+ cells in 25 CLL samples. Positive cases for ZAP70 and CD72 were defined using a cut-off of 35% and 40% positive cells, respectively. Real time PCR was used to quantify the expression levels of 3 genes related to proliferation and survival, RELB, Beta-Catenin (CTNNB1) and AKT1, on 16 CD19+ enriched (purity > 90%) CLL samples. Results: Samples were classified as 11 ZAP70+ and 14 ZAP70−. Median percentage of CD72+ cells in ZAP70+ was significantly higher than for ZAP70− cases (82% compared to 39%, respectively, P=0.0029). Furthermore, percentages of CD72 and ZAP70 were positively correlated (r=0.5930 and P=0.0009). Interestingly, ZAP70+ cases were restricted to CD72+ cases (n=11, CD72+ZAP70+ [+/+]), whereas six CD72+ cases were ZAP70− (ZAP70−CD72+ [−/+]). Finally, there were 8 cases CD72−ZAP70− [−/−]. No differences among these 3 groups were observed in regard to laboratory parameters (white blood cells, total lymphocytes, lymphocyte percentage, haemoglobin, haematocrit and platelet number). Despite the reduced number of samples analysed (6 +/+, 6 −/− and 4 −/+), transcripts for RELB (P<0.05), CTNNB1 (P<0.05), and AKT1(P=0.057) were expressed at higher levels in ZAP70+CD72+ than in ZAP70−CD72+ samples. Additionally, the transcripts were expressed at higher levels in ZAP70−CD72− than in ZAP70−CD72+ samples, and this difference was statistically significant (P<0.05) for CTNB1 and AKT1, but not for RELB (P=0.054). Conclusion: Our data indicate that higher percentages of ZAP70+ cells are associated with higher expression levels of transcripts related to proliferation and survival of CLL B-cells. In the absence of ZAP70 expression, CD72 may act as a negative regulator of the BCR pathway, as indicated by the lowest levels of transcripts on ZAP70−CD72+ cases.

Abnormal Free Light Chain Ratios in Chronic Lymphocytic Leukemia: A New Prognostic Factor?.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1237-1237 ◽  
Author(s):  
Johannes Matschke ◽  
Lewin Eisele ◽  
Ludger Sellmann ◽  
Ulrich Duehrsen ◽  
Jan Duerig ◽  
...  
Keyword(s):  
Prognostic Factor ◽  
Chronic Lymphocytic Leukemia ◽  
Conflicts Of Interest ◽  
Prognostic Significance ◽  
Risk Groups ◽  
Typical Feature ◽  
Lymphocytic Leukemia ◽  
Al Amyloidosis ◽  
Abnormal Ratio

Abstract Abstract 1237 Poster Board I-259 Introduction Free light chains (FLC) have prognostic significance in monoclonal gammopathy of undetermined significance, solitary plasmocytoma of bone, smouldering myeloma, multiple myeloma, Waldenstroms macroglobulinaemia and AL amyloidosis. Although monoclonal protein secretion is a typical feature of plasma cell dyscrasias, it can also be detected in other B cell malignancies including chronic lymphocytic leukemia (CLL). Recent data suggest a significant correlation between abnormal ratio of FLC and outcome. Therefore, we investigated FLC in a large cohort of 120 patients in order to assess the role of FLC in CLL. Methods and Results Plasma samples which had been previously cryopreserved and collected at the time before the initiation of therapy or six months after finishing therapy were used. The levels of FLC were assessed using nephelometric immunoassays (The Binding Site) and quantified nephelometrically with the BNII analyser. A normal FLC range (κlγ) was defined as 0.26-1.65. Moreover, in all cases we evaluated the M band on immunofixation (IF). Abnormal FLC ratios were found in 71 patients (59%) whereas the IF was positive in only 32 cases (27%). In 48 cases the FLC ratio was positive while IF was negative and in only 9 cases the IF was positive while the FLC ratio was normal. In total, 23 patients had both a positive IF and an abnormal FLC ratio. Patients with an abnormal FLC ratio for γ had a significantly shorter treatment-free survival (TFS) than patients with an abnormal ratio for κ or with a normal FLC ratio (median TFS: 34 versus 78 versus 109 months, p=0.042). Evaluation of several disease characteristics in association with FLC of the patients' B-CLL cells showed no significant differences for FLC in the different risk groups (ZAP-70 status, CD38 status, cytogenetics and Binet stage) suggesting no correlation of the FLC with these already established adverse prognostic factors. Conclusion FLC can be detected in a substantial fraction of patients with CLL and the FLC technique improves detection of M-proteins. Moreover, an abnormal FLC ratio is associated with worse outcome, particularly those with a low abnormal FLC ratio. Evaluation of the prognostic significance of abnormal FLC in a larger cohort is currently under way. This data will be presented at the meeting. Future studies are warranted to elucidate the role of FLC as biomarkers of disease and as a prognostic factor for response. Disclosures No relevant conflicts of interest to declare.

B Cell Activating Factor and c-Myc Regulate the Progression of Chronic Lymphocytic Leukemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 359-359
Author(s):  
Weizhou Zhang ◽  
Arnon P. Kater ◽  
Han-Yu Chuang ◽  
Thomas Enzler ◽  
George F. Widhopf ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Disease Progression ◽  
Cell Population ◽  
Lymphocytic Leukemia ◽  
Leukemia Cells ◽  
Low Grade ◽  
B Cell Activating Factor

Abstract Abstract 359 Chromosomal translocations involving c-Myc are frequently found in high grade lymphoma and multiple myeloma. In contrast, c-Myc translocations rarely occur in low-grade lymphomas/leukemias like chronic lymphocytic leukemia (CLL), but when present they are associated with rapid disease progression and bad prognosis. Overexpression of c-myc may also be the result of increased transcription by several proto-oncogene transcription factors, including NF-kB. Mice with c-Myc de-regulation at different stages of B cell development develop either aggressive B cells lymphomas or plasma cell neoplasm. So far, no c-Myc mouse model developed low-grade lymphoma/leukemia. iMycCa mice develop an expansion of CD5+ peritoneal B1 cells, as compared with WT littermates mice. These mice have a normal life-span and very rarely develop B cell lymphoma at older age. Interestingly, in iMycCa mice mature B cells, but not plasma cells,could be rescued from apoptosis by administration of B cell-activating factor belonging to the TNF family (BAFF). To our surprise, double transgenic iMycCa/Baff-Tg (Myc/Baff) mice developed a disease resembling human CLL, with dramatically shorter mean survival than parental strains, due to early onset and rapid clonal expansion of a mature CD5+B220low B cell population. Those cells transferred the disease into Baff-Tg (Baff) mice with marked infiltration in lymphoid organs and bone marrow. Gene-expression analyses revealed that among the genes altered in Myc/Baff CD5+B220lowleukemia cells were those with known relevance to human CLL disease, including elevated anti-apoptotic Bcl2 family members. Apart from studies on individual genes, sub-network analysis was performed which showed enrichment of apoptosis-related and stress-induced gene sets in Myc/Baff CD5+CD3- leukemia cells. The NF-kB gene set, a major target downstream of BAFF signaling, was also enriched in Myc/Baff CD5+CD3- leukemia cells. We observed a continuum in levels of c-MYC mRNA in 166 samples using Affymetrix array analyses. Changes in c-Myc protein expression were confirmed by immunoblot analyses and correlated with disease progression. In accordance with the functions of c-Myc as a promoter of cell cycle progression, as well as apoptosis, we found enhanced spontaneous cell death in vitro in CLL cells expressing high levels of c-Myc, which could be abrogated by co culture with BAFF expressing nurse-like cells (NLC) or recombinant BAFF. In addition to its anti-apoptotic role, BAFF treatment of primary human CLL cells led to dramatically enhanced expression of c-Myc through the IKK/NF-kB pathway. Inhibition of the NF-kB pathway significantly reduced viability of both Myc/Baff CD5+CD3- leukemia cells and human CLL cells co-cultured with NLC. Also it significantly lowered CD5+B220low leukemia cell population in blood and spleen, and prevented the infiltration of leukemia cells into lymph nodes and bone marrow of transplanted mice. This study demonstrates a potential pathologic role for c-Myc, in the pathogenesis and progression of CLL. Disclosures: No relevant conflicts of interest to declare.

Dysregulation of TNFα-Induced Necroptotic Signaling In Chronic Lymphocytic Leukemia: Suppression of CYLD Gene by LEF1

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 377-377 ◽  
Author(s):  
Peng Liu ◽  
Bei Xu ◽  
Jianyong Li
Keyword(s):  
Cell Death ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Death Receptors ◽  
Lymphocytic Leukemia ◽  
Ros Production ◽  
A Genome ◽  
Stimulation Of

Abstract Abstract 377 Impaired cell death program has been noted as one of the hallmarks of Chronic lymphocytic leukemia (CLL) and contributes to its accumulation of malignant monoclonal B cells as well as to chemotherapy resistance. A cell can die through apoptosis or necrosis pathway. While apoptosis is known as a regulated cellular program, necrosis is known as an accidental event caused by overwhelming stress. However, accumulating evidence suggests that necrosis can also be executed by regulated mechanisms, especially in apoptotic-deficient conditions. Recently, the term necroptosis has been used to designate one particular form of programmed necrosis induced by stimulating death receptors with agonists such as TNFα, FasL, and TRAIL. Apoptosis suppression by caspase inhibitors such as zVAD may switch apoptotic response to necroptosis or enhance necroptosis. In contrast to well-characterized apoptotic pathway, the detailed molecular mechanisms underlying necroptosis are still not fully understood. A genome wide siRNA screen revealed two members of the receptor interacting protein (RIP) kinase family, RIP1 and RIP3P, to be essential for necroptosis. Upon stimulation of death receptors, RIP3 is recruited to RIP1 to form a necroptosis-inducing complex which is essential for cell death execution. The deubiquitinase cylindromatosis (CYLD) is recruited to TNFα receptor upon its activation and directly regulates RIP1 ubiquitination. In addition, by activating key enzymes of metabolic pathways, RIP3 regulates TNFα-inducing mitochondrial reactive oxygen species (ROS) production, which partly accounts for its ability to potentiate necroptosis. Until now, much less is known about the significance of necroptosis in malignant disease. Here we demonstrate that primary CLL cells failed to undergo necroptosis upon stimulation of TNFα combined with pan-caspase inhibitor zVAD. Upon TNFα+zVAD stimulation, normal CD19+ B cells increased ROS production > 8 fold, while same treatment only resulted in ∼ 2 fold induction in ROS generation in CLL samples. Two core components of necroptotic machine, RIP3 and CYLD, are markedly down-regulated in CLL compared with normal B cells, at both protein and transcription levels. Moreover, we identified LEF1, a downstream effector of Wnt/β-catenin pathway, as a transcription repressor of CYLD in CLL. LEF1 is highly expressed in CLL cells, whereas normal B cells have very low levels of LEF1 expression. Attenuation of LEF1 expression through RNAi technology resulted in a dramatic increase in CYLD levels in CLL cells, as determined by western blot and real time RT-PCR analysis. Dual-luciferase assays showed that forced expression of LEF1 markedly decreased CYLD promoter activity compared with controls. Mutation of LEF1 responsive elements (LERs) on CYLD promoter significantly abolished transcriptional repression of CYLD by LEF1. Chromatin immunoprecipitation assays showed that LEF1 is recruited to LER region within the CYLD promoter in CLL cells. Additionally, Knocking down LEF1 sensitizes CLL cells to TNFα-induced necroptosis. The present investigation provides the first evidence that CLL cells have defects not only in apoptotic program but also in necroptotic signaling. Targeting the key regulators of necroptotic machine such as LEF1 to restore this pathway may represent a novel approach for CLL treatment. Disclosures: No relevant conflicts of interest to declare.

CCR4:CCL17 Interaction Influences TLR-9 Mediated Cell Survival and Proliferation In Chronic Lymphocytic Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3593-3593
Author(s):  
Sonal C. Temburni ◽  
Ryon M. Andersen ◽  
Luke Janson ◽  
Xiao-Jie Yan ◽  
Barbara Sherry ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Conflicts Of Interest ◽  
Dose Range ◽  
Serum Levels ◽  
Lymphocytic Leukemia ◽  
Novel Therapy

Abstract Abstract 3593 Unlike other hematologic disorders, chronic lymphocytic leukemia(CLL) exhibits remarkable heterogeneity in the rates of disease progression among cases. CLL cells survive by receiving signals from the microenvironment via various receptors: B-cell antigen receptor (BCR), Toll-like receptors (TLRs) and cytokine and chemokine receptors. We previously reported that CLL clones with somatically mutated IGHVs and high (≥30%) percentage of CD38 expressing cells have the highest percentage of CCR4-expressing cells. To further explore the functional contribution of the CCR4:CCL17 axis in CLL, we studied CCL17-induced chemotactic behavior in 16 CLL cases. In transwell cultures we observed a bimodal migratory response to CCL17 at 2 doses in a dose range of 0.78– 25ng/ml, in ~60% of cases; the remaining cases showed maximal migration at a single dose (1.56 or 3.12ng/ml). A comparison of phenotypes of the migrated and non-migrated cell populations was undertaken in 10 cases, analyzing CXCR3, CXCR4, CCR4 and CCR7 that are involved in homing of cells to sites favoring growth, and CD31, CD38 and CD69, activation related molecules. The migrated cells consistently showed significantly higher percentages and densities of CD38 expression than the non-migrated cells suggesting a role for CD38 in the CCR4-mediated downstream pathway. CCR4 ligand, CCL17, is constitutively expressed in the thymus and is produced by dendritic cells, endothelial cells, keratinocytes and fibroblasts, whereas CCL22 is produced by tumor cells and the tumor microenvironment. Serum levels of both these ligands in untreated patients were quantified by ELISA. CCL17 levels ranged between 45-1, 229 pg/ml in U-CLL cases (n=23) and between 43-1, 418 pg/ml in M-CLL cases (n=30). CCL22 levels ranged between 121-5, 497 pg/ml in U-CLL cases (n=23) and 409-5, 502 pg/ml in M-CLL cases (n=30). The percentages of CCR4- expressing B cells directly correlated with percentages of T cells expressing CCR4 in individual cases, whereas they inversely correlated with both, serum levels of CCL17 (p< 0.01) and CCL22 (p< 0.05). CCL17 produced by DCs in peripheral organs may exert an accessory role in BCR- and TLR-9-mediated immune responses in B cells. We therefore tested if CCL17 supported BCR- and TLR-mediated proliferative responses in a cohort of 31 (16 U-CLL and 15M-CLL) CLL cases. CCL17 augmented BCR-mediated B-cell proliferation in 9/16 (56%) U-CLL cases, but only in 3/15 (20%) M-CLL cases. On the other hand, CCL17 showed an additive effect in promoting TLR-9-mediated cell proliferation in 13/15 (87%) M-CLL cases at a dose of 2ng/nl (approximating that detected in serum); it also augmented TLR-9 mediated B cell proliferation in 6/16 U-CLL cases but at a 5-fold or higher dose (10-25 ng/ml). In a subset of this cohort (8 cases) CCL17-induced modulation of molecules involved in the apoptotic process was studied. We found upregulation of anti-apoptotic proteins Mcl-1 and Bcl2 and down-regulation of pro-apoptotic molecules Bim, PUMA, and Bid in 5 of these cases. The pro-survival effects of CCL17 were partially abrogated by the blocking anti-CCR4 mAb (1G1). Taken together, these findings suggest that CCL17 plays a role in modulating TLR-9-mediated signaling and migration in CLL. Therefore, inhibition of CCR4:CCL17 interaction in vivo represents a novel therapy by preventing migration of CLL cells towards an environment that promotes their survival. Disclosures: No relevant conflicts of interest to declare.

Immune Thrombocytopenia Associated to Low-Dose Alemtuzumab Therapy in Chronic Lymphocytic Leukemia: A Single Retrospective Center Experience

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4598-4598
Author(s):  
Gianluigi Reda ◽  
Francesco Maura ◽  
Giuseppe Gritti ◽  
Daniele Vincenti ◽  
Mariarita Sciumé ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Disease Progression ◽  
Cumulative Dose ◽  
Immune Thrombocytopenia ◽  
Low Dose ◽  
Conflicts Of Interest ◽  
Autoimmune Disorder ◽  
Intravenous Immunoglobulins ◽  
Lymphocytic Leukemia ◽  
Platelet Counts

Abstract Abstract 4598 Immune thrombocytopenia (ITP) is a common autoimmune complication in chronic lymphocytic leukemia (CLL), occurring in up to 5% of patients. The occurrence of alemtuzumab-associated ITP have been rarely reported in CLL and it has never been reported so far as a significant event complicating alemtuzumab treatment in clinical trials. Recently, a new distinctive form of secondary ITP occurring in 6 out of 215 patients with relapsing-remitting multiple sclerosis treated with alemtuzumab in a randomized, controlled phase II trial has been reported (Cuker et al, Blood 2011). We investigated the incidence of ITP in a cohort of 64 consecutive patients treated with low-dose alemtuzumab for relapsed/refractory CLL from 2003 to 2010. Subcutaneous alemtuzumab was administered at the dose of 10 mg three times a week, up to 18 weeks. ITP was documented in 12/64 patients: in 3 patients (4.7%) ITP developed before alemtuzumab treatment and no relapses of the autoimmune disorder were observed during the treatment; in 9 patients (14.8%, with an incidence of 5.7 events/100 patient-year) ITP developed after alemtuzumab treatment. Median time to ITP from initial alemtuzumab exposure was 12 months (range 1–42 months). Concomitant hemolytic anemia (Evans syndrome) was observed in one patient. At ITP onset, median platelet counts were 11×109/L (range 3–70) and anti-platelet antibodies (Capture P® Method, ImmucorGamma, Norcross GA, USA) were found in 7 of the 8 patients tested. No patients showed severe or life-threatening bleeding. Three of nine patients who developed ITP after alemtuzumab therapy, experienced CLL progression requiring chemo-immunotherapy after 3, 4 and 13 months from ITP onset, respectively. One patient achieved a partial remission of CLL with ITP resolution, while the other two died of disease progression. In the remaining six cases, ITP was not associated with disease progression and was treated with corticosteroids and/or intravenous immunoglobulins. Five patients achieved normal platelet counts, while one patient did not respond. Low-dose alemtuzumab (theoretical cumulative dose 540 mg, equal to half of the classic cumulative dose and one-third of the individual dose) is an effective, safe and well tolerated treatment for CLL, as reported by several recent studies (Cortelezzi et al, Leukemia 2009; Brit J Haematol 2011). In our cohort of CLL patients treated with alemtuzumab, the incidence of ITP was 14.8% that is almost three times higher than previously reported in CLL. These data may indicate a role of T-lymphocyte dysregulation induced by alemtuzumab in the pathogenesis of ITP. Our data also suggested the importance of monitoring platelet counts during follow-up in patients treated with low-dose alemtuzumab for both haematological and non-haematological diseases. Disclosures: No relevant conflicts of interest to declare.

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