scholarly journals Cell Enrichment for FISH: A Novel Diagnostic Tool in Challenging Cases of Low Bone Marrow Involvement By Mature B-Cell Neoplasms

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2992-2992
Author(s):  
Farzad Nooraie ◽  
J. Dianne Keen-Kim ◽  
Derek Denton Lyle ◽  
Shannon Dingivan ◽  
Austin Mauch ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Detection Rate ◽  
Cell Detection ◽  
Employment Equity ◽  
Cell Enrichment ◽  
Equity Ownership ◽  
Blood Specimens

Abstract Cytogenetic studies are useful tools which can provide diagnostic, prognostic and management information for mature B-cell neoplasms. Mature B-cells do not grow well in cytogenetic cultures. Therefore, detection, characterization and differentiation of scant mature B-cell neoplasms or minimal residual disease can be difficult in bone marrow or peripheral blood specimens. FISH provides more sensitive information than G-band chromosome analysis. However, in cases with low-level involvement of the marrow, abnormal FISH results may be missed or not reported when abnormalities do not exceed experimentally determined cut-off values. To increase the sensitivity of abnormal mature B-cell detection, we developed an enrichment method utilizing pan B-cell antibodies. This method separates mature B-cells from the remaining bone marrow and/or peripheral blood cells. We selected 59 bone marrow and peripheral blood specimens from patients referred for mature B-cell neoplasms (except for myeloma) for use in the validation. These specimens had 1% to 10% monoclonal mature B-cells detected by flow cytometry and were enriched using cell-separating technologies. Each specimen was divided into four equal portions, with three of four portions undergoing enrichment using different pan B-cell antibodies. The fourth portion was reserved for standard non-enriched testing and was used for comparison to results obtained in the enriched portions. A variety of corresponding FISH analyses were performed in each of the four portions, based upon the disease state. FISH results were obtained by two independent scoring technologists. Enrichment with B-cell antibodies improved detection of FISH abnormalities that may not have otherwise been observed in the patient specimens. 42% (25/59) of samples had abnormalities detected within the enriched portion that were not detected in the standard non-enriched portion. Of these, 64% (16/25) had a FISH abnormality that was a critical finding for the final diagnosis, prognosis and/or management of the patient. Enrichment also increased the sensitivity of FISH abnormality detection. 29% (17/59) of samples had abnormalities that were detected in both the enriched and non-enriched portions. However, detection was on average 15-fold more sensitive. The average detection rate of FISH abnormalities in the non-enriched portion was 3%, which is at or near the experimentally determined cut-off value for most FISH probes. In contrast, the average detection rate of FISH abnormalities in the enriched portion was 56%. In 5% (3/59) of cases, detection of FISH aberrations in enriched specimens helped to distinguish two separate neoplastic processes in the bone marrow. These results demonstrate the increased opportunity for detecting FISH aberrations in enriched versus non-enriched specimens. Mature B-cell enrichment and subsequent FISH testing in cases of scant mature B-cell neoplastic involvement of the bone marrow and/or peripheral blood is a novel and powerful cytogenetic technique. This technique enriches bone marrow and/or peripheral blood specimens for targeted abnormal cells and increases the number of those cells analyzed by FISH testing, thus allowing for a higher detection rate of genetic abnormalities. Disclosures Nooraie: Genoptix Inc., A Novartis Company: Employment, Equity Ownership. Keen-Kim:Genoptix Inc., A Novartis Company: Employment, Equity Ownership. Lyle:Genoptix Inc., A Novartis Company: Employment, Equity Ownership. Dingivan:Genoptix Inc., A Novartis Company: Employment, Equity Ownership. Mauch:Genoptix Inc., A Novartis Company: Employment, Equity Ownership. Lynes:Genoptix Inc., A Novartis Company: Employment. Castillo:Genoptix Inc., A Novartis Company: Employment. Kolker:Genoptix Inc., A Novartis Company: Employment. Cancino:Genoptix Inc., A Novartis Company: Employment, Equity Ownership.

CC-122 Degrades the Lymphoid Transcription Factor Aiolos (IKZF3) By Modulating Cereblon and Shows Clinical Activity in a Phase Ib Study of Subjects with Relapsed or Refractory Non-Hodgkin’s Lymphoma and Multiple Myeloma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3500-3500 ◽  
Author(s):  
Vincent Ribrag ◽  
Silvia Damien ◽  
Mecide Gharibo ◽  
Mercede Gironella ◽  
Armando Santoro ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
Single Dose ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Memory T Cells ◽  
Cell Lymphoma ◽  
Employment Equity ◽  
Equity Ownership

Abstract Background: CC-122 is a novel non-phthalimide analog of the IMiDs® immunomodulatory drugs (lenalidomide and pomalidomide) and a first in class PPMTM (Pleiotropic Pathway Modifier) compound with multiple biological activities including potent anti-proliferative activity against B-lineage cells (10-fold greater than lenalidomide), anti-angiogenic activity (100-fold greater than lenalidomide) and immunomodulatory effects (10-fold greater than lenalidomide). The molecular target of CC-122 is cereblon (CRBN), a substrate receptor of the Cullin ring E3 ubiquitin ligase complex (CRL4CRBN). CC-122 promotes ubiquitination of lymphoid transcription factors Ikaros (IKZF1) and Aiolos (IKZF3) in a CRBN-dependent manner, leading to their subsequent degradation. Following establishment of 3mg once daily (QD) as the maximum tolerated dose (Blood 122:2905 2013), patients with advanced aggressive non-Hodgkin lymphoma (NHL), multiple myeloma (MM), and select solid tumors were enrolled in parallel expansion cohorts of up to 20 evaluable patients. CC-122 was dosed at 3 mg QD in 28-day cycles until disease progression. Results: As of May 1, 2014, 93 total patients were enrolled in the expansion phase of the study. The NHL cohort included 21 patients with diffuse large B-cell lymphoma (DLBCL) and 1 patient with mantle cell lymphoma, and twenty-four patients were enrolled in the MM cohort. Results in solid tumor cohorts will be reported separately. All patients were ECOG performance status 0-2, the median number of prior systemic therapies was 4 (NHL) and 6 (MM). The most common (> 20%) adverse events (AEs) (grades 1-4) included neutropenia (69.6%), anemia (52%), asthenia (50%), pyrexia (35%), diarrhea (30%), cough (30%), thrombocytopenia (28%), and constipation (22%). Grade 3/4 AEs occurring in more than one patient were neutropenia (52%), anemia (26%), febrile neutropenia (13%), and thrombocytopenia (7%). CC-122 dose reduction was required in 36.4% of patients with NHL and 63% of patients with MM, the majority of which was due to neutropenia and occurred during cycle 1 or 2. CC-122 systemic exposure in NHL and MM patients was generally comparable after administration of single and multiple doses. Peak concentrations were observed between 30 minutes and 2 hours (median Tmax concentration = 1.5 h). Four treated patients with DLBCL had objective responses; one patient with complete response (CR) and 3 with partial responses (PR). Responses were observed in patients with germinal center B cell (GCB), non-GCB and Myc/Bcl2 over-expressing DLBCL. Four treated patients with MM had PR, and two of these responders were progression free beyond 10 cycles. A single dose of CC-122 3mg resulted in decreased Aiolos protein expression at 1.5 and 5 hours compared with baseline in peripheral B cells (median 38% and 53%) and T cells (median 31% and 54%) in the combined NHL (n = 16) and MM (n = 19) cohorts. Decrease in expression of Aiolos protein from baseline was also observed in lymph node biopsies of patients with DLBCL. Furthermore, CC-122 treatment decreased CD19+ B cells (median = 57% of baseline), expanded CD4-/CD8+/CD45RA-/CD45RO+ cytotoxic memory T cells (median = 320% of baseline), and expanded CD4+/CD8-/CD45RA-/CD45RO+ helper memory T cells (median = 154% of baseline) in peripheral blood samples from patients with MM (n = 9) and NHL (n = 3-12) subjects. Additionally, ex vivo activation of T cells after a single dose of CC-122 compared with baseline, as measured by IL-2 production, increased by a median of 776% (NHL n = 3 and MM n = 7). Conclusions: CC-122 shows promising initial clinical and pharmacodynamic activity in heavily pretreated relapse/refractory NHL and MM patients. Biomarker analysis indicates that the 3 mg QD dose of CC-122 results in rapid CRBN target engagement and Aiolos degradation in the peripheral blood lymphocytes of patients with NHL and MM patients and in NHL tumor tissue. Exploration of an intermittent dosing to mitigate neutropenia-related dose reductions and interruptions is ongoing and clinical studies exploring drug combinations with CC-122 are underway. Disclosures Ribrag: Celgene Corp: Consultancy. Rasco:Celgene Corp: Membership on an entity's Board of Directors or advisory committees. Wei:Celgene Corp: Employment, Equity Ownership. James:Celgene Corp: Employment. Hagner:Celgene Corp: Employment, Equity Ownership. Gandhi:Celgene Corp: Employment, Equity Ownership. Chopra:Celgene Corp: Employment, Equity Ownership. DiMartino:Celgene Corp: Employment, Equity Ownership. Pourdehnad:Celgene Corp: Employment, Equity Ownership. Stoppa:Celgene Jansen: Honoraria.

Targeted Depletion of B-Cell Subsets by Anti-CD22 and Anti-CD79bAntibody Drug Conjugates: Illumination of the Mechanism of Action through Pharmacodynamic Biomarkers

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3923-3923
Author(s):  
Franklin Fuh ◽  
Caroline Looney ◽  
Dongwei Li ◽  
Kirsten Achilles Poon ◽  
Randall Dere ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Mechanism Of Action ◽  
Peripheral Blood ◽  
Employment Equity ◽  
Ki 67 ◽  
Cynomolgus Monkeys ◽  
Drug Conjugates ◽  
Equity Ownership

Abstract Abstract 3923 CD22 and CD79b are cell surface receptors whose expression is limited to B-cells. Both CD22 and CD79b are expressed on NHL and CLL patient B-cells, as well as on relapsed NHL B-cells (Dornan et al., 2009; Polson et al., 2010). In order to develop a target specific therapy for the treatment of CLL and NHL, we generated anti-CD22 and anti-CD79b antibody drug conjugates (ADCs) linked to an auristatin, a potent anti-mitotic drug that disrupts cellular mitosis through inhibition of tubulin polymerization. Preliminary efficacy data have shown that these ADCs have significant activity in preclinical xenograft models of NHL, while minimal activity was observed with the unconjugated antibody (AG Polson et al, 2010). To evaluate the cellular effects and characterize the mechanism of action (MOA) of these ADCs, we have examined the pharmacokinetics and the pharmacodynamic effects in non-human primates. Substantial B cell depletion was observed after administration of either anti-CD22-ADC or anti-CD79b-ADC to cynomolgus monkeys. By comparison, the extent and duration of B cell depletion was less substantial in animals dosed with unconjugated anti-CD22 or anti-CD79b antibodies. We evaluated several potential mechanisms for the depletion, including antibody opsonization, antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and internalization of drug conjugates which leads to subsequent intracellular release of cytotoxic drug and cell death. Our data from in vitro anti-CD22 studies showed minimal to no ADCC or CDC activity, suggesting that these mechanisms play little to no role in vivo. Consistent with the expected MOA of ADCs, we observed depletion of proliferating splenic follicular germinal center B cells in cynomolgus monkeys following dosing with anti-CD22 ADC. Furthermore, in studies with either anti-CD22-ADC or anti-CD79b-ADC, preferential depletion of proliferating Ki67+ B lymphocytes (compared to Ki67- B lymphocytes) was observed in peripheral blood of ADC-dosed animals, and not in animals dosed with the unconjugated antibody or with vehicle control. This preferential depletion was observed on Days 8 and 15, but was not seen on Day 21 or at subsequent time points, which correlated with the expected serum clearance of the ADC. In contrast, we observed that administration of either ADC resulted in a dose-dependent decrease in circulating non-proliferating B cells one day after dosing. Taken together, these observations agree with the proposed mechanism of action of initial depletion of both proliferating and non-proliferating B cells via antibody-mediated opsonization at early time points after dosing (1-2 days) with subsequent preferential depletion of proliferating B lymphocytes mediated by the auristatin component of the anti-CD22 and anti-CD79b ADCs. These data support CD22 and CD79b ADCs as promising candidate therapeutics for the treatment of NHL and CLL, as both anti-CD22 and anti-CD79b drug conjugates are capable of targeting Ki-67+ (proliferating) B cells in lymphoid tissues and peripheral blood. In CLL, Ki-67+ cells in bone marrow have been hypothesized to represent pathogenic ‘stem’ cells, and our preliminary data indicate increased percentages of Ki-67+ B cells in the peripheral blood of CLL patients compared to normal healthy adults. As both anti-CD22 and anti-CD79b ADCs specifically deplete proliferating B cells, the development of these ADCs represents an effective way to target proliferating pathogenic B cells in NHL and CLL, and offers a more favorable risk-benefit profile than traditional chemotherapeutic agents. Disclosures: Fuh: Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Looney:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Li:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Poon:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Dere:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Ramakrishnan:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Polson:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Prabhu:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership. Williams:Genentech/Hoffmann-La Roche Inc.: Employment, Equity Ownership.

scholarly journals Preclinical Mechanistic Studies Investigating Neutrophil and Lymphoid Cell Depletion By IMGN529, a CD37-Targeting Antibody-Drug Conjugate (ADC)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3119-3119 ◽  
Author(s):  
Jutta Deckert ◽  
Jose F. Ponte ◽  
Jennifer A. Coccia ◽  
Leanne Lanieri ◽  
Sharon Chicklas ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cell ◽  
Peripheral Blood ◽  
Blood Cells ◽  
Peripheral Blood Cells ◽  
Employment Equity ◽  
Normal Human ◽  
Equity Ownership

Abstract CD37 is a surface antigen widely expressed on malignant B cells in non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). In normal tissues, CD37 expression is restricted to lymphoid tissues and blood cells, with high levels of expression on B lymphocytes and low levels on non-B lymphoid and myeloid cells. IMGN529 is a CD37-targeting ADC currently in a Phase I clinical study in adult patients with relapsed or refractory NHL (NCT01534715). This ADC uniquely combines the intrinsic pro-apoptotic and immune effector activities of its anti-CD37 antibody component with the potent cytotoxic mechanism provided by targeted delivery of its maytansinoid payload, DM1. In the Phase I study, IMGN529 has demonstrated early evidence of clinical activity. A reduction in lymphocyte counts was also observed in the majority of patients after dosing, consistent with the proposed mechanism of action of a CD37-targeted therapy. However, in the initial dose-escalation phase, some patients experienced transient, early-onset neutropenia. To investigate the potential mechanisms of this transient neutropenia observed in patients, different pre-clinical models were considered and utilized to recapitulate clinical findings. In vitro studies with peripheral blood cells from normal human donors demonstrated that incubation with IMGN529 for 1 hour or 24 hours resulted in significant B-cell depletion with no apparent neutrophil depletion detected, similar to observations after rituximab treatment. In contrast, alemtuzumab treatment in vitro resulted in both B-cell and neutrophil depletion. This is consistent with the high level of CD37 expression on target B cells and the relatively low CD37 expression level on other blood cells. Analysis of cytokine release by normal human donor peripheral blood cells incubated with IMGN529 revealed increased levels of IL-8, CCL2 (MCP-1) and CCL4 (MIP-1β), but not IL-6 or TNF, to a similar extent as rituximab but less pronounced than alemtuzumab. An anti-murine CD37 antibody was identified to enable in vivo studies in a murine model and characterize CD37 expression on murine blood cells. Similar to the expression profile of CD37 in human peripheral blood cells, CD37 expression on murine peripheral blood cells was highest in B cells, with much lower expression seen on T cells and granulocytes. In vivo activity of the anti-muCD37 antibody and the corresponding ADC, with the same SMCC-DM1 linker-payload combination as IMGN529, was evaluated to discern antibody and payload-mediated events in comparison to the classic cytotoxic cyclophosphamide (CPA). Treatment of C57/B6 mice with 1-10 mg/kg of anti-muCD37 antibody or anti-muCD37 ADC resulted in a significant decrease in absolute lymphocyte counts (ALC) lasting greater than 7 days and a transient decrease in absolute neutrophil counts (ANC) lasting 1-2 days. A non-targeted control SMCC-DM1 ADC had no effect on ALC or ANC counts, suggesting the decrease is a CD37-mediated effect. In contrast, treatment with CPA resulted in an ALC decrease with similar kinetics but a more pronounced ANC decline. No impact on bone marrow lymphocyte, myeloid or erythroid precursor cell counts was observed in response to the anti-muCD37 antibody or anti-muCD37 ADC, whereas CPA treatment caused reduced cellularity with a decrease in the percentage of mature myeloid precursors and neutrophils in bone marrow. Elevated levels of CCL2 and CCL4 chemokines were detected in mouse plasma after anti-muCD37 ADC treatment, which may contribute to a redistribution of circulating neutrophils into peripheral tissues. Studies are currently underway to assess neutrophil distribution in murine tissues post anti-muCD37 ADC treatment. Current preclinical studies provide no clear evidence for direct IMGN529-mediated depletion of normal human neutrophils in the context of B-cell depletion in vitro. In vivo studies with an anti-muCD37 ADC recapitulate transient peripheral lymphopenia and neutropenia with no impact on bone marrow precursors observed, indicative of a different mechanism than classic chemotherapy-induced bone marrow myelosuppression. These preliminary results suggest a role for chemokine-mediated neutrophil redistribution following CD37 engagement, which is the subject of further studies. Disclosures Deckert: ImmunoGen, Inc.: Employment, Equity Ownership. Ponte:ImmunoGen, Inc.: Employment, Equity Ownership. Coccia:ImmunoGen, Inc.: Employment, Equity Ownership. Lanieri:ImmunoGen, Inc.: Employment, Equity Ownership. Chicklas:ImmunoGen, Inc.: Employment, Equity Ownership. Yi:ImmunoGen, Inc.: Employment, Equity Ownership. Watkins:ImmunoGen, Inc.: Employment, Equity Ownership. Ruiz-Soto:ImmunoGen, Inc.: Employment, Equity Ownership; sanofi: Employment. Romanelli:ImmunoGen, Inc.: Employment, Equity Ownership; sanofi: Employment. Lutz:ImmunoGen, Inc.: Employment, Equity Ownership.

scholarly journals Sequence Level Analysis of Hodgkin Lymphoma Clonotypes Detected in Peripheral Blood Using a Next-Generation Sequencing Approach

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1610-1610
Author(s):  
Yasuhiro Oki ◽  
Sattva S. Neelapu ◽  
Michelle Fanale ◽  
Larry W. Kwak ◽  
Luis Fayad ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Expression Level ◽  
Employment Equity ◽  
Tumor Biopsy ◽  
Cellular Compartment ◽  
Equity Ownership ◽  
Level Analysis

Abstract Background: Classical Hodgkin lymphoma (CHL) has been established as B-cell malignancy characterized by a clonal expansion of pathognomonic Reed Sternberg cells (Marafioti et al. Blood 2000). A previous report suggests that clonotypic B-cells may be present in the blood of patients with CHL; however, the relationship between these circulating clonotypic B-cells and CHL is unclear. We utilized the LymphoSIGHT™ method, a next-generation sequencing approach, to detect lymphoma-specific clonotypes in peripheral blood in patients with CHL at diagnosis or disease recurrence as well as in follow-up blood samples. This method has the sensitivity to detect one lymphoma cell per million leukocytes in peripheral blood, and has been applied to minimal residual disease (MRD) detection in multiple B-cell malignancies. We evaluated the extent of somatic hypermutation in the lymphoma clonotypes, and performed sequence and expression level analyses of the lymphoma clonotype repertoire. Methods: Frozen primary tumor biopsy samples were first analyzed for clonality at the immunoglobulin heavy chain (IGH) and kappa chain (IGK) loci using the LymphoSIGHT method. Rearranged immunoglobulin gene segments (IGH-VDJ, IGH-DJ and IGK) in the genomic DNA and/or RNA were amplified with locus-specific primer sets, sequenced, and analyzed using standardized algorithms for clonotype determination. Clonotypes with a frequency >5% in the B-cell repertoire of the tumor biopsy were considered to represent tumor clonotypes. IGH-VDJ clonotypes with a frequency >2% in DNA were deemed to be cancer-specific if the clonotype was not present in the RNA. Such clonotypes were then quantitated in serum and peripheral blood mononuclear cells (PBMC), and DNA sequence and/or RNA expression level analysis was performed. Results: A total of 17 CHL patients were analyzed. A high-frequency clonal rearrangement was identified for at least one receptor (IGH-VDJ, IGH-DJ and IGK) in 12 of 17 cases (71%). Lymphoma-specific clonotypes were detected in blood samples from 8 of 11 patients (73%). Notably, a lymphoma-specific clonotype was detected in the serum compartment in 8 of 9 cases (89%) tested (Figure 1A), while it was detected in PBMC only in 3 of 9 cases (33%) tested (Figure 1B). Follow-up samples obtained from three patients in remission were negative for the tumor-specific clonotype in both the serum and cellular compartments. We conducted sequence and expression level analysis of each IGH-VDJ clonal rearrangement. We calculated the number of somatic mutations in each lymphoma-specific clonotype compared to the germline sequence in the interrogated region. In the ten patients with IGH-VDJ clonal rearrangements, we observed a median of 14 somatic mutations (range 0 to 27). This confirms that HRS cells correspond in their developmental stage to germinal or post-germinal center B-cells. While IGH-VDJ clonotypes were observed frequently in DNA obtained at diagnosis, IGH-VDJ clonotypes were not detected in the RNA from the same sample. We evaluated the relationship between the presence of lymphoma-specific clonotypes in the cellular compartment at diagnosis and eventual progression. All three untreated patients that were positive at baseline in the cellular compartment experienced relapse or progression (at 3, 11 and 17 months). In contrast, zero of 5 patients without detectable lymphoma-specific clonotypes in their cellular compartment at baseline experienced relapse (follow up duration 23-45 months, log-rank test p=0.004). Conclusions: This is the first clinical assay that can be used to detect and monitor MRD in CHL. Lymphoma-specific sequences can be identified in serum in 80% of cases. Our preliminary analysis suggests that the presence of lymphoma-specific clonotypes in PBMCs may indicate high risk for recurrence. This study demonstrates proof-of-principle and underscores the promise of a new methodology to measure disease burden and provide prognostic information from a blood test in patients with CHL. Figure 1. Lymphoma clonotype levels in A) cell-free plasma and B) PBMC samples are shown for the different patients. Figure 1. Lymphoma clonotype levels in A) cell-free plasma and B) PBMC samples are shown for the different patients. Figure 2 Figure 2. Disclosures Klinger: Sequenta, Inc.: Employment, Equity Ownership. Carlton:Sequenta, Inc.: Employment, Equity Ownership. Kong:Sequenta, Inc.: Employment, Equity Ownership. Faham:Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Detection of Diffuse Large B-Cell Lymphoma in Peripheral Blood Using High-Throughput Sequencing Assay.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2666-2666
Author(s):  
Yasuhiro Oki ◽  
Malek Faham ◽  
Victoria Carlton ◽  
Sattva S. Neelapu ◽  
Anas Younes
Keyword(s):  
B Cell ◽  
Peripheral Blood ◽  
High Throughput Sequencing ◽  
B Cell Lymphoma ◽  
Lymph Node Biopsy ◽  
Employment Equity ◽  
Tumor Biopsy ◽  
Blood Samples ◽  
Large B Cell Lymphoma ◽  
Equity Ownership

Abstract Abstract 2666 Background: In patients with diffuse large B-cell lymphoma (DLBCL), circulating lymphoma cells in the bloodstream are rarely detected by conventional morphology or flow cytometry evaluation. We developed a high-throughput sequencing based platform, LymphoSIGHT, to detect evidence of lymphoid malignancies in peripheral blood samples, as this could potentially be used for detection of minimal residual disease after treatment. This sequencing method has a sensitivity to detect one lymphoma cell per million leukocytes in peripheral blood. We herein report the results of our pilot study assessing the ability of this method to detect the lymphoma clone in peripheral blood samples from 5 DLBCL patients at the time of diagnosis. Methods: This study has been approved by IRB and consent has been obtained from patients. Using universal primer sets, we amplified immunoglobulin heavy chain (IgH@) variable, diversity, and joining gene segments from genomic DNA in tumor biopsy and peripheral blood samples (plasma and peripheral blood mononuclear cell (PBMC) compartments) collected at initial diagnosis. Amplified products were sequenced to obtain >1 million reads (>10× sequencing coverage per IgH molecule), and were analyzed using standardized algorithms for clonotype determination. Tumor-specific clonotypes were identified for each patient based on their high-frequency within the B-cell repertoire in the lymph node biopsy sample. The presence of the tumor-specific clonotype was then quantitated in cell-free and PBMC compartments from the diagnostic blood sample. A quantitative and standardized measure of clone level among all leukocytes in the diagnostic sample was determined using internal reference DNA. Results: We detected a high-frequency IgH clonal rearrangement in all 5 lymph node biopsy samples. The lymphoma clonotype that was identified in the tumor biopsy was also detected in the plasma and/or PBMC compartment in all 5 patients at diagnosis. Specifically, the lymphoma clonotype was detected in the plasma compartment in 4 patients, while 3 patients demonstrated the presence of the lymphoma clonotype in the PBMC compartment (Table 1). We hypothesize that the positive lymphoma clone in the plasma is due to rapid proliferation and necrosis of the primary tumor, releasing the degraded component of lymphoma into the blood stream. However, in this small sample size, we did not observe an obvious correlation between the level of detection (PBMC or plasma) and clinical parameters (LDH, stage, size of tumor, tumor Ki67, cell-of-origin). All patients achieved complete response after initial treatment and four are being followed. We plan to analyze blood specimens while they are in remission. Conclusions: IgH clonal rearrangements were detected by sequencing in all tumor biopsy samples. Importantly, all peripheral blood samples showed signs of circulating lymphoma material in either the plasma or PBMC compartment at diagnosis. Analysis of diagnostic and post-therapy samples from additional DLBCL patients is ongoing. These data will determine whether the sequencing assay is a strong indicator for response to therapy and relapse monitoring. Disclosures: Faham: Sequenta, Inc.: Employment, Equity Ownership, Research Funding. Carlton:Sequenta, Inc.: Employment, Equity Ownership, Research Funding.

scholarly journals Regulated Expression of Human Histocompatibility Leukocyte Antigen (HLA)-DO During Antigen-dependent and Antigen-independent Phases of B Cell Development

2002 ◽  
Vol 195 (8) ◽  
pp. 1053-1062 ◽  
Author(s):  
Xinjian Chen ◽  
Oskar Laur ◽  
Taku Kambayashi ◽  
Shiyong Li ◽  
Robert A. Bray ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Class Ii ◽  
Cell Development ◽  
B Cell Development ◽  
Negative Regulator ◽  
Leukocyte Antigen ◽  
Peptide Loading

Human histocompatibility leukocyte antigen (HLA)-DO, a lysosomal resident major histocompatibility complex class II molecule expressed in B cells, has previously been shown to be a negative regulator of HLA-DM peptide loading function. We analyze the expression of DO in human peripheral blood, lymph node, tonsil, and bone marrow to determine if DO expression is modulated in the physiological setting. B cells, but not monocytes or monocyte-derived dendritic cells, are observed to express this protein. Preclearing experiments demonstrate that ∼50% of HLA-DM is bound to DO in peripheral blood B cells. HLA-DM and HLA-DR expression is demonstrated early in B cell development, beginning at the pro-B stage in adult human bone marrow. In contrast, DO expression is initiated only after B cell development is complete. In all situations, there is a striking correlation between intracellular DO expression and cell surface class II–associated invariant chain peptide expression, which suggests that DO substantially inhibits DM function in primary human B cells. We report that the expression of DO is markedly downmodulated in human germinal center B cells. Modulation of DO expression may provide a mechanism to regulate peptide loading activity and antigen presentation by B cells during the development of humoral immune responses.

scholarly journals An All Antibody Approach for Conditioning Bone Marrow for Hematopoietic Stem Cell Transplantation with Anti-cKIT and Anti-CD47 in Non-Human Primates

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4428-4428
Author(s):  
Kristopher D Marjon ◽  
James Y Chen ◽  
Jiaqi Duan ◽  
Timothy S Choi ◽  
Kavitha Sompalli ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Stem Cell ◽  
Peripheral Blood ◽  
Research Funding ◽  
Mast Cell Degranulation ◽  
Employment Equity ◽  
Cell Counts ◽  
Equity Ownership

Background Hematopoietic stem cell (HSC) transplantation (HSCT) is a well-established procedure that, with or without gene therapy, is curative for numerous severe life-threatening diseases including genetic blood disorders and blood cancers. While advances have been made, there are still substantial concerns since these chemo- and radiation therapy based procedures cause long-term toxicities such as infertility and secondary malignancies or even result in high mortality. We have previously established in a series of preclinical studies a novel chemo- and radiation-free non-toxic monoclonal antibody (Ab) -based conditioning regimen for autologous and allogeneic HSCT (Czechowicz et al., Akanksha et al. and George et al.). This cKIT-CD47 Ab-based regimen selectively depletes host HSCs for HSCT while sparing off-target toxicities caused by chemotherapy/radiation. By significantly decreasing morbidity/mortality associated with traditional conditioning regimens, antibody-mediated conditioning could expand the patient population eligible to receive HSCT for a variety of disorders. We developed a novel cKIT Ab (FSI-174), with an active Fc, and in combination with our CD47 magrolimab (previously 5F9, blocks the don't eat me pathway) could be utilized to translate the promising preclinical findings into clinical studies for safe and less toxic bone marrow conditioning for HSCT. Here we present the functional characterization of FSI-174 as single Ab and in combination with magrolimab in vitro and in non-human primate (NHP) studies. Methods We tested if FSI-174 could block stem cell factor signaling and we explored if FSI-174 alone or in combination with magrolimab could promote phagocytosis of cKIT positive cells (Kasumi-1). In addition, we determined if FSI-174 could cause mast cell degranulation. Subsequently, we explored the potential of FSI-174 alone (Phase A) or in combination with magrolimab (Phase B) to deplete HSCs in NHPs (rhesus macaques)in vivo. In Phase A, single doses of FSI-174 (0.3, 1, or 3 mg/kg) were administered alone. In Phase B, FSI-174 (0.3 or 3 mg/kg) was administered in combination with magrolimab (5mg/kg priming and 20 mg/kg maintenance dose). Bone marrow aspirates and core biopsies and peripheral blood were sampled before the study start and throughout the study. Frequency of bone marrow HSCs and cKIT receptor occupancy (RO) was determined by flow cytometry. In addition, the PK profile of FSI-174 was determined. Results In-vitro analysis demonstrated that FSI-174 decreases proliferation of HSPCs and enhances phagocytosis of cKIT positive cells, and the addition of magrolimab synergistically enhances the phagocytosis. Strikingly, FSI-174 did not cause mast cell degranulation in vitro. In the NHPs, complete (100%) cKIT receptor occupancy was achieved at all FSI-174 dose levels and was maintained for 1 to 9 days correlating with increasing doses and pharmacokinetics. The FSI-174 Cmax was found to be proportional to dose and mean Cmax increased from 6.25 ug/mL to 49.2 ug/mL. In Phase A, FSI-174 alone did not decrease the frequency of bone marrow HSCs compared to PBS control and had no effect on the peripheral blood cell counts. However, in Phase B, when FSI-174 was combined with magrolimab it significantly decreased the frequency of bone marrow HSCs with the nadir at day 9 and no recovery over 85 days compared to PBS control. Notably, there were no changes in peripheral blood cell counts over the course of the studies with no cytopenias in combination treatment. Conclusions We have developed a novel cKIT Ab (FSI-174) that meets the desired profile of stem cell factor block, promotion of phagocytosis, but without promoting mast cell degranulation. Furthermore, in the NHPs studies we have confirmed our chemo- and radiation-free cKIT-CD47 Ab -based conditioning approach with FSI-174 and magrolimab. As anticipated by our previous preclinical studies, monotherapy with FSI-174 does not deplete bone marrow HSCs in NHPs. Notably, no cytopenias are observed with either monotherapy or combination therapy. These data demonstrate the specificity, efficacy and safety of FSI-174/ magrolimab combination have great potential for conditioning regimen for HSCT in a chemotherapy and radiation free manner. Given the favorable safety profile of magrolimab across several clinical studies, these results are paving the way to the first-in-human trials for this novel conditioning for HSCT. Disclosures Marjon: Forty Seven Inc: Employment, Equity Ownership. Chen:Forty Seven Inc.: Consultancy, Equity Ownership. Duan:Forty Seven Inc.: Employment, Equity Ownership. Choi:Forty Seven inc: Employment, Equity Ownership. Sompalli:Forty Seven Inc: Employment, Equity Ownership. Feng:Forty Seven Inc: Employment, Equity Ownership. Mata:Forty Seven inc: Employment, Equity Ownership. Chen:Forty Seven Inc: Employment, Equity Ownership. Kean:HiFiBio: Consultancy; BlueBirdBio: Research Funding; Gilead: Research Funding; Regeneron: Research Funding; EMDSerono: Consultancy; FortySeven: Consultancy; Magenta: Research Funding; Bristol Meyers Squibb: Patents & Royalties, Research Funding; Kymab: Consultancy; Jazz: Research Funding. Chao:Forty Seven Inc: Employment, Equity Ownership. Chao:Forty Seven, Inc.: Employment, Equity Ownership, Patents & Royalties. Takimoto:Forty Seven, Inc.: Employment, Equity Ownership, Patents & Royalties. Agoram:Forty Seven Inc.: Employment, Equity Ownership. Majeti:FortySeven: Consultancy, Equity Ownership, Other: Board of Director; BioMarin: Consultancy. Weissman:Forty Seven Inc.: Consultancy, Equity Ownership, Patents & Royalties. Liu:Forty Seven Inc: Employment, Equity Ownership, Patents & Royalties. Volkmer:Forty Seven, Inc.: Employment, Equity Ownership, Patents & Royalties.

scholarly journals A Novel CD20xCD3 Bispecific Fully Human Antibody Induces Potent Anti-Tumor Effects Against B Cell Lymphoma in Mice

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4501-4501 ◽  
Author(s):  
Bindu Varghese ◽  
Jayanthi Menon ◽  
Luis Rodriguez ◽  
Lauric Haber ◽  
Kara Olson ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Tumor Cells ◽  
Bispecific Antibody ◽  
Tumor Regression ◽  
Employment Equity ◽  
Cynomolgus Monkeys ◽  
Nsg Mice ◽  
Equity Ownership

Abstract Bispecific antibodies that redirect effector T cells to kill tumor cells have shown considerable promise in both pre-clinical and clinical studies. However, these bispecific formats can have short half-lives necessitating constant infusion of the molecules into patients. We report here on a novel full-length human IgG CD20xCD3 bispecific antibody (REGN1979) that targets CD20 expressed on normal and malignant B cells and CD3 expressed on T cells in humans and cynomolgus monkeys. Our results demonstrate CD20-target cell-dependent activation and cytokine release by T cells, and efficient redirected T cell lysis of target tumor cells. Raji B cell lymphomas grown as tumors in NOD SCID IL2R gamma deficient (NSG) mice and co-implanted with human peripheral blood mononuclear (PBMC) cells were completely inhibited when treated at the time of implantation with a low dose (0.004 mg/kg; 2x/week) of REGN1979. As expected, T cells were required for this tumor inhibition, since treatment in the absence of human T cells was not effective. REGN1979 bispecific antibody also demonstrated potent activity against other tumor cells expressing CD20, as it significantly delayed CD20-transduced B16F10.9 tumor growth in immune-competent mice. Most importantly, REGN1979 induced dramatic tumor regression in large advanced (500-900 mm3) Raji tumors, associated with long-lasting tumor control. The tumor-infiltrating lymphocytes (TILs) in B cell lymphomas in these untreated NSG mice were found to express the inhibitory receptors Tim-3 and PD-1 and were the predominant fraction of T cells in the tumors and in the circulation. T cells in mice treated with REGN1979 showed decreased Tim-3 and PD-1 expression in the circulation accompanied by complete tumor regression. In further studies, REGN1979 (dosed at 0.4 mg/kg; 2x/week) was superior to rituximab therapy (dosed at 8 mg/kg; 5x/week) and comparable to the CD19xCD3 BiTE (dosed at 0.5 mg/kg; 5x/week) in suppressing established Raji tumors (200-400mm3). Pre-clinical studies in cynomolgus monkeys to assess activity of the bispecific antibody for depleting B cells in circulation and various lymphoid organs showed that a single injection of REGN1979 (0.1 mg/kg) was more potent at depleting CD20+ B cells in the mesenteric lymph nodes than a high dose of rituximab (30 mg/kg). In separate studies, REGN1979 was also found to have a long half-life (>14 days) in the circulation of monkeys following depletion of B cells. These studies show potent activity of a new class of fully human bispecific antibodies for treating tumors, and support clinical testing of REGN1979 in patients with CD20+ cancers. Figure 1 Figure 1. Disclosures Varghese: Regeneron Pharmaceuticals: Employment, Equity Ownership. Menon:Regeneron Pharmaceuticals: Employment, Equity Ownership. Rodriguez:Regeneron Pharmaceuticals: Employment, Equity Ownership. Haber:Regeneron Pharmaceuticals: Employment, Equity Ownership. Olson:Regeneron Pharmaceuticals: Employment, Equity Ownership. Duramad:Regeneron Pharmaceuticals: Employment, Equity Ownership. Oyejide:Regeneron Pharmaceuticals: Employment, Equity Ownership. Smith:Regeneron Pharmaceuticals: Employment, Equity Ownership. Thurston:Regeneron Pharmaceuticals: Employment, Equity Ownership. Kirshner:Regeneron Pharmaceuticals: Employment, Equity Ownership.

scholarly journals First-in-Human, Phase 1/2 Trial to Assess the Safety and Clinical Activity of Subcutaneous GEN3013 (DuoBody®-CD3×CD20) in B-Cell Non-Hodgkin Lymphomas

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 758-758 ◽  
Author(s):  
Pieternella Lugtenburg ◽  
Rogier Mous ◽  
Michael Roost Clausen ◽  
Martine E.D. Chamuleau ◽  
Peter Johnson ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Board Of Directors ◽  
Dose Escalation ◽  
Research Funding ◽  
Clinical Activity ◽  
Employment Equity ◽  
Advisory Committees ◽  
Equity Ownership

Introduction: CD20-specific monoclonal antibodies (mAbs) have demonstrated efficacy in the treatment of B-cell non-Hodgkin lymphomas (B-NHL); however, a significant proportion of patients (pts) present with refractory disease or will experience relapse. GEN3013 (DuoBody®-CD3×CD20) is the first subcutaneously administered IgG1 bispecific antibody (bsAb) that targets the T-cell surface antigen CD3 and the B-cell surface antigen CD20, triggering T-cell-mediated killing of B cells. In vitro, GEN3013 efficiently activates and induces cytotoxic activity of CD4+ and CD8+ T cells in the presence of B cells (Hiemstra et al. Blood 2018), and results in long-lasting depletion of B cells in cynomolgus monkeys. Subcutaneous (SC) GEN3013 in cynomolgus monkeys resulted in lower plasma cytokine levels, and similar bioavailability and B-cell depletion, compared with intravenous administration. GEN3013 has higher potency in vitro than most other CD3×CD20 bsAbs in clinical development (Hiemstra et al. HemaSphere 2019). SC GEN3013 in pts with B-NHL is being evaluated in a first-in-human, Phase 1/2 trial (NCT03625037), which comprises a dose-escalation part and a dose-expansion part. Here we report preliminary dose-escalation data. Methods: Pts with CD20+ B-NHL with relapsed, progressive, or refractory disease following anti-CD20 mAb treatment, and ECOG PS 0-2 were included. During dose escalation, pts received SC GEN3013 flat dose in 28-day cycles (q1w: cycle 1-2; q2w: cycle 3-6; q4w thereafter) until disease progression or unacceptable toxicity. Risk of cytokine release syndrome (CRS) was mitigated with the use of a priming dose and premedication with corticosteroids, antihistamines, and antipyretics. Primary endpoints were adverse events (AEs) and dose-limiting toxicities (DLTs). Secondary endpoints included pharmacokinetics (PK), immunogenicity (anti-drug antibodies [ADA]), pharmacodynamics (PD) (cytokine measures; laboratory parameters), and anti-tumor activity (tumor size reduction; objective and best response). Results: At data cut-off (June 28, 2019), 18 pts were enrolled into the dose-escalation part of the trial, with safety data available for pts receiving doses starting at 4 µg. Most pts had diffuse large B-cell lymphoma (DLBCL; n=14) and were heavily pre-treated; 10 pts had received ≥3 prior lines of therapy (overall median [range]: 3 [1-11]). The median age was 58.5 years (range: 21-80), and 13 pts were male. At a median follow-up of 1.9 months, pts received a median of 5 doses (range: 1-14); treatment is ongoing in 6 pts. Twelve pts discontinued treatment due to progressive disease. Six pts died (2 during treatment, 4 during survival follow-up), all due to disease progression and unrelated to treatment. The most common (n≥5) treatment-emergent AEs were pyrexia (n=8), local injection-site reactions (n=7), diarrhea (n=5), fatigue (n=5), and increased aspartate aminotransferase (n=5). The most common Grade (G) 3/4 AEs were anemia (n=3) and neutropenia (n=3). Despite increasing GEN3013 doses, all CRS events were non-severe (initial observation: 3/8 pts, G1: n=1, G2: n=2; following modification of premedication plan [corticosteroids for 3 days]: 6/10 pts, G1: n=4, G2: n=2). Increases in peripheral cytokine (IL6, IL8, IL10, IFNγ, TNFα) concentrations after GEN3013 dosing correlated with clinical symptoms of CRS in most pts. No pts had tumor lysis syndrome or neurological symptoms. No DLTs were observed. GEN3013 PK profiles reflect SC dosing; Cmax occurred 2-4 days after dosing. No ADAs were detected. PD effects following GEN3013 dosing were observed at dose levels as low as 40 µg and included rapid, complete depletion of circulating B cells (if present after prior anti-CD20 therapy) and peripheral T-cell activation and expansion. The first evidence of clinical activity was observed at a dose level of 120 µg, with complete metabolic response observed in a pt with DLBCL. Conclusions: Subcutaneously administered GEN3013, a potent CD3×CD20 bsAb, shows good tolerability and early evidence of clinical activity at low dose levels in heavily pretreated pts with relapsed or refractory B-NHL. All CRS events were non-severe and did not lead to discontinuation. No DLTs were observed. Dose escalation is ongoing; updated data will be presented. Dose expansion will begin upon determining the recommended Phase 2 dose (RP2D) (NCT03625037). Disclosures Lugtenburg: Janssen Cilag: Honoraria; Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria; Servier: Consultancy, Honoraria, Research Funding; Genmab: Consultancy, Honoraria; BMS: Consultancy; Takeda: Consultancy, Honoraria, Research Funding. Mous:Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Sandoz: Honoraria; Roche: Honoraria; Abbvie: Honoraria; Takeda: Honoraria, Research Funding; Janssen Cilag: Consultancy, Honoraria; MSD: Honoraria; Gilead: Consultancy, Honoraria, Research Funding. Clausen:Abbvie: Other: Travel grant to attend ASH 2019. Johnson:Boehringer Ingelheim: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Honoraria; Epizyme: Honoraria, Research Funding; Incyte: Honoraria; Takeda: Honoraria; Genmab: Honoraria; Bristol-Myers Squibb: Honoraria; Kite: Honoraria; Novartis: Honoraria. Rule:Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Astra-Zeneca: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pharmacyclics: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria; TG Therapeutics: Consultancy, Honoraria; Napp: Consultancy; Kite: Consultancy. Oliveri:Genmab: Employment, Equity Ownership. DeMarco:Genmab: Employment, Equity Ownership. Hiemstra:Genmab: Employment, Equity Ownership, Other: Warrants. Chen:Genmab: Employment. Azaryan:Genmab: Employment. Gupta:Genmab: Employment, Equity Ownership. Ahmadi:Genmab Inc: Employment, Other: stock and/or warrants. Hutchings:Incyte: Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Janssen: Research Funding; Pfizer: Research Funding.

Increased Apoptosis of Peripheral Blood and Bone Marrow B and T Cells Correlates with Advanced Stages and Poor Risk Factors in Patients with B-CLL

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4162-4162
Author(s):  
Malgorzata Sieklucka ◽  
Agnieszka Bojarska-Junak ◽  
Agata Surdacka ◽  
Iwona Hus ◽  
Ewa Wasik-Szczepanek ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Disease Progression ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Lymphocytic Leukemia ◽  
High Rate ◽  
Advanced Stage

Abstract B-cell chronic lymphocytic leukemia (B-CLL), is characterized by the accumulation of long-lived, neoplastic B-lymphocytes in peripheral blood, bone marrow and secondary lymphoid organs. Apoptotic processes have been shown to be altered in leukemic B cells, however, the role of apoptosis in the mechanisms of disease progression remains unclear. Recent studies suggest that the clonal excess of B-cells is caused not only by a decrease in cell death but also by increased cell proliferation. We have recently reported on a high rate of apoptosis leukemic B cells in peripheral blood (PB) of advanced stage patients and that apoptosis of PB lymphocytes from advanced-stage (III–IV acc. Rai) patients is higher than that in early-stage (0–II acc. Rai) patients. However the spontaneous apoptosis in B-CLL patients was significantly lower compared to the healthy controls that confirmed the defective apoptosis as one of the mechanisms of leukemic lymphocytes accumulation in B-CLL. Continuing our research, in the presented study we measured apoptosis of B and T cells in peripheral blood and bone marrow in correlation with the stage of B-CLL and prognostic factors. Materials and methods: Peripheral blood and bone marrow (BM) samples were obtained from 120 previously untreated B-CLL patients. An analysis of apoptosis within the B and T cells population was performed using flow cytometer and chloromethyl-X-rosamine staining (Mito Tracker Red CMXRos). CMXRos was used to detect disruptions in the mitochondrial membrane potential (ΔΨm), which is one of the earliest events in the apoptotic pathway and allow finding apoptotic cells when there are still in PB and BM. We found that ex vivo lymphocyte apoptosis was higher in BM compared to PB (p<0.05). Moreover, both B-cell and T-cell apoptosis in BM was higher than in PB (p<0.0001 and p<0.001, respectively). When compared, ex vivo apoptosis of T cells was found higher than that of B cells, both in BM (p<0.0001) and PB (p<0.0001). The percentage of apoptotic leukemic B cells correlated negatively with Bcl-2/Bax ratio in CD19+ B cells (p<0.05). Similarly, the percentage of apoptotic CD3+ cells correlated negatively with Bcl-2/Bax ratio in CD3+ cells (p<0.01). We also found that the percentage of apoptotic leukemic B cells correlated positively with the expression of proapoptotic protein Par-4 (prostate apoptosis response-4) in CD19+ B cells (p<0.01). The expression of Par-4 protein in CD19+ B cells correlated positively with the percentage of CD38+ cells (p<0.05), and it was higher in patients with CD38+ and ZAP-70+/CD38+ phenotypes (p<0.05 and p<0.01, respectively). There was a positive correlation between the expression of Par-4 protein and the lactate dehydrogenase (LDH) and β2-microglobulin serum concentrations (p<0.01 and p<0.05, respectively). Furthermore, the percentage of apoptotic CD19+ cells correlated positively with the LDH serum level (p<0.05). These data indicate that high amount of apoptotic leukemic cells in PB and BM might be considered as poor prognosis factor. Higher rate of B and T cells apoptosis in BM than in PB suggest the influence of bone marrow microenviroment on this process. Our results indicate also that high rate of T cells apoptosis might be responsible for immune dysfunction including both impaired anti-infection immunity as well as impaired anti-cancer response resulting in disease progression.

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