scholarly journals bcl-2 gene hypomethylation and high-level expression in B-cell chronic lymphocytic leukemia

Blood ◽  
1993 ◽  
Vol 82 (6) ◽  
pp. 1820-1828 ◽  
Author(s):  
M Hanada ◽  
D Delia ◽  
A Aiello ◽  
E Stadtmauer ◽  
JC Reed
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Lines ◽  
Methylation Status ◽  
Peripheral Blood Lymphocytes ◽  
Lymphocytic Leukemia ◽  
Low Grade ◽  
Gene Rearrangements ◽  
Normal Peripheral Blood ◽  
Cell Chronic Lymphocytic Leukemia

The bcl-2 gene becomes transcriptionally deregulated in the majority of low-grade non-Hodgkin lymphomas as a result of t(14;18) translocations that place the bcl-2 gene at 18q21 into juxtaposition with the Ig heavy- chain locus at 14q32. This chromosomal translocation or similar bcl-2 gene rearrangements involving the Ig light-chain genes have been reported to occur in some cases of B-cell chronic lymphocytic leukemia (B-CLL). We analyzed the structure, methylation, and expression of the bcl-2 gene in 20 cases of B-CLL or closely related variants of this lymphoproliferative disorder, including at least 16 typical examples of CD5+ B-CLL. None of the 20 specimens had evidence of bcl-2 gene rearrangements, based on Southern blot analysis using three different bcl-2 probes. However, immunoblot analysis using antibodies specific for the Bcl-2 protein showed that 14 of 20 cases (70%) contained levels of p26-Bcl-2 that were equal to or greater than those found in a t(14;18)-bearing lymphoma cell line. Furthermore, in 19 of 20 cases (95%), the Bcl-2 protein was present at levels that were 1.7- to 25- fold higher than in normal peripheral blood lymphocytes. These differences in the relative levels of Bcl-2 protein among cases of B- CLL appeared to be functionally significant, in that a preliminary analysis of 3 representative cases showed that CLL cells with higher levels of Bcl-2 protein survived longer in culture and were delayed in their onset of DNA degradation relative to CLL cells with lower Bcl-2 protein levels. Evaluation of the methylation status of the bcl-2 gene using the isoschizomers Msp I and Hpa II, and a probe corresponding to the first major exon of the gene showed complete demethylation of both copies of the bcl-2 gene in a region corresponding to a 2.4-kb Msp I fragment in all 20 cases of B-CLL. In contrast, analysis of 6 of 6 B- cell lines that harbor a t(14;18) was consistent with hypomethylation of only one of the two bcl-2 alleles. Neither copy of the bcl-2 gene was demethylated in this region in 5 of 5 lymphoid cell lines that lack this translocation. However, hypomethylation of the bcl-2 gene did not necessarily correlate with the relative levels of Bcl-2 protein present in the B-CLL cells, suggesting that additional mechanisms for regulating bcl-2 expression are involved.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals bcl-2 gene hypomethylation and high-level expression in B-cell chronic lymphocytic leukemia

Blood ◽  
1993 ◽  
Vol 82 (6) ◽  
pp. 1820-1828 ◽  
Author(s):  
M Hanada ◽  
D Delia ◽  
A Aiello ◽  
E Stadtmauer ◽  
JC Reed
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Lines ◽  
Methylation Status ◽  
Peripheral Blood Lymphocytes ◽  
Lymphocytic Leukemia ◽  
Low Grade ◽  
Gene Rearrangements ◽  
Normal Peripheral Blood ◽  
Cell Chronic Lymphocytic Leukemia

Abstract The bcl-2 gene becomes transcriptionally deregulated in the majority of low-grade non-Hodgkin lymphomas as a result of t(14;18) translocations that place the bcl-2 gene at 18q21 into juxtaposition with the Ig heavy- chain locus at 14q32. This chromosomal translocation or similar bcl-2 gene rearrangements involving the Ig light-chain genes have been reported to occur in some cases of B-cell chronic lymphocytic leukemia (B-CLL). We analyzed the structure, methylation, and expression of the bcl-2 gene in 20 cases of B-CLL or closely related variants of this lymphoproliferative disorder, including at least 16 typical examples of CD5+ B-CLL. None of the 20 specimens had evidence of bcl-2 gene rearrangements, based on Southern blot analysis using three different bcl-2 probes. However, immunoblot analysis using antibodies specific for the Bcl-2 protein showed that 14 of 20 cases (70%) contained levels of p26-Bcl-2 that were equal to or greater than those found in a t(14;18)-bearing lymphoma cell line. Furthermore, in 19 of 20 cases (95%), the Bcl-2 protein was present at levels that were 1.7- to 25- fold higher than in normal peripheral blood lymphocytes. These differences in the relative levels of Bcl-2 protein among cases of B- CLL appeared to be functionally significant, in that a preliminary analysis of 3 representative cases showed that CLL cells with higher levels of Bcl-2 protein survived longer in culture and were delayed in their onset of DNA degradation relative to CLL cells with lower Bcl-2 protein levels. Evaluation of the methylation status of the bcl-2 gene using the isoschizomers Msp I and Hpa II, and a probe corresponding to the first major exon of the gene showed complete demethylation of both copies of the bcl-2 gene in a region corresponding to a 2.4-kb Msp I fragment in all 20 cases of B-CLL. In contrast, analysis of 6 of 6 B- cell lines that harbor a t(14;18) was consistent with hypomethylation of only one of the two bcl-2 alleles. Neither copy of the bcl-2 gene was demethylated in this region in 5 of 5 lymphoid cell lines that lack this translocation. However, hypomethylation of the bcl-2 gene did not necessarily correlate with the relative levels of Bcl-2 protein present in the B-CLL cells, suggesting that additional mechanisms for regulating bcl-2 expression are involved.(ABSTRACT TRUNCATED AT 400 WORDS)

Cytokine-Release Syndrome in Patients With B-Cell Chronic Lymphocytic Leukemia and High Lymphocyte Counts After Treatment With an Anti-CD20 Monoclonal Antibody (Rituximab, IDEC-C2B8)

Blood ◽  
1999 ◽  
Vol 94 (7) ◽  
pp. 2217-2224 ◽  
Author(s):  
U. Winkler ◽  
M. Jensen ◽  
O. Manzke ◽  
H. Schulz ◽  
V. Diehl ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Adverse Events ◽  
B Cell ◽  
Tumor Cells ◽  
Lymphocytic Leukemia ◽  
Low Grade ◽  
Cytokine Release ◽  
Cytokine Release Syndrome ◽  
Anti Cd20 ◽  
Cell Chronic Lymphocytic Leukemia

Eleven patients with relapsed fludarabine-resistant B-cell chronic lymphocytic leukemia (CLL) or leukemic variants of low-grade B-cell non-Hodgkin’s lymphoma (NHL) were treated with the chimeric monoclonal anti-CD20 antibody rituximab (IDEC-C2B8). Peripheral lymphocyte counts at baseline varied from 0.2 to 294.3 × 109/L. During the first rituximab infusion, patients with lymphocyte counts exceeding 50.0 × 109/L experienced a severe cytokine-release syndrome. Ninety minutes after onset of the infusion, serum levels of tumor necrosis factor- (TNF-) and interleukin-6 (IL-6) peaked in all patients. Elevated cytokine levels during treatment were associated with clinical symptoms, including fever, chills, nausea, vomiting, hypotension, and dyspnea. Lymphocyte and platelet counts dropped to 50% to 75% of baseline values within 12 hours after the onset of the infusion. Simultaneously, there was a 5-fold to 10-fold increase of liver enzymes, d-dimers, and lactate dehydrogenase (LDH), as well as a prolongation of the prothrombin time. Frequency and severity of first-dose adverse events were dependent on the number of circulating tumor cells at baseline: patients with lymphocyte counts greater than 50.0 × 109/L experienced significantly more adverse events of National Cancer Institute (NCI) grade III/IV toxicity than patients with less than 50.0 × 109/L peripheral tumor cells (P= .0017). Due to massive side effects in the first patient treated with 375 mg/m2 in 1 day, a fractionated dosing schedule was used in all subsequent patients with application of 50 mg rituximab on day 1, 150 mg on day 2, and the rest of the 375 mg/m2 dose on day 3. While the patient with the leukemic variant of the mantle-cell NHL achieved a complete remission (9 months+) after treatment with 4 × 375 mg/m2 rituximab, efficacy in patients with relapsed fludarabine-resistant B-CLL was poor: 1 partial remission, 7 cases of stable disease, and 1 progressive disease were observed in 9 evaluable patients with CLL. On the basis of these data, different infusion schedules and/or combination regimens with chemotherapeutic drugs to reduce tumor burden before treatment with rituximab will have to be evaluated.

Pharmacokinetic Study of Single Doses of Oral Fludarabine Phosphate in Patients With “Low-Grade” Non-Hodgkin's Lymphoma and B-Cell Chronic Lymphocytic Leukemia

1999 ◽  
Vol 17 (5) ◽  
pp. 1574-1574 ◽  
Author(s):  
James M. Foran ◽  
David Oscier ◽  
Jennifer Orchard ◽  
Stephen A. Johnson ◽  
Mary Tighe ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Intravenous Administration ◽  
Pharmacokinetic Study ◽  
Lymphocytic Leukemia ◽  
Hodgkin's Lymphoma ◽  
Low Grade ◽  
Fludarabine Phosphate ◽  
Non Hodgkin's Lymphoma ◽  
Cell Chronic Lymphocytic Leukemia

PURPOSE: Fludarabine phosphate (F-AMP), a purine analog, requires daily intravenous administration. A pharmacokinetic study of an oral formulation (10 mg immediate-release tablet) was undertaken in patients with “low-grade” non-Hodgkin's lymphoma and B-cell chronic lymphocytic leukemia. PATIENTS AND METHODS: Oral F-AMP was incorporated into the “conventional” treatment schedule. Single oral trial doses of 50, 70, and 90 mg of F-AMP were given on the first day of three cycles of treatment; a comparative 50-mg intravenous trial dose was given on the first day of the fourth cycle. Intravenous F-AMP (25 mg/m2) was given on days 2 to 5 at 4-week intervals. Pharmacokinetic samples taken after each trial dose were analyzed for plasma 2-fluoro-arabinofuranosyl-adenine (2F-ara-A) concentration (its main metabolite); area under the curve 0 to 24 hours (AUC(0-24h)) and maximum concentration (Cmax) were calculated. Eighteen patients received all three oral trial doses, and bioavailability was determined in 15 patients who completed four courses of therapy. RESULTS: Oral administration of F-AMP resulted in a dose-dependent increase in Cmax and AUC(0-24h) of 2F-ara-A and achieved an AUC(0-24h) similar to intravenous administration, although at a lower Cmax. The linear increase in mean AUC(0-24h) by factors of 1.36 ± 0.22 (mean ± SD) and 1.72 ± 0.31 corresponded well with the increase in oral dose from 50 to 70 mg (factor of 1.4) and 90 mg (factor of 1.8), respectively. Bioavailability (approximately 55%, with low intraindividual variation) and time to Cmax were dose independent. CONCLUSION: Oral doses of F-AMP can achieve an AUC(0-24h) of 2F-ara-A similar to intravenous administration, with dose-independent bioavailability. The tablet will greatly enhance the use of F-AMP in a palliative setting.

Comprehensive Analysis of BAFF Binding Receptor Profiles and Receptor Occupancy in B Cell Chronic Lymphocytic Leukemia: Identification of Discrete Phenotypic Subgroups.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1135-1135
Author(s):  
Renee C. Tschumper ◽  
Jaime R. Darce ◽  
Xiaosheng Wu ◽  
Stephen A. Mihalcik ◽  
Diane F. Jelinek
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Activation ◽  
Receptor Occupancy ◽  
Lymphocytic Leukemia ◽  
B Cell Activation ◽  
Normal Peripheral Blood ◽  
Fold Induction ◽  
Cell Chronic Lymphocytic Leukemia

Abstract B cell-activating factor (BAFF) is known to regulate normal B cell development and homeostasis primarily by signaling through the high affinity receptor, BAFF-R, one of three BAFF binding receptors (BBRs). BAFF also binds two other receptors, BCMA and TACI with lesser affinity. We have recently shown that normal peripheral blood (PB) B cells express high levels of prebound soluble BAFF, which is lost upon B cell activation. Because of BAFF’s activity on normal B cells, we have been interested in the roles of BAFF and BBRs in B cell chronic lymphocytic leukemia (B-CLL). We and others have demonstrated that BAFF promotes primary CLL B cell survival and that serum BAFF levels are elevated in some patients. Although CLL B cells are known to express BBRs, a comprehensive and quantitative analysis of BBR levels and CLL B cell capacity to bind BAFF has not yet been done. We began this study by characterizing the level of soluble BAFF bound to freshly isolated CLL B cells, measured by both western blot analysis and flow cytometry. To assess receptor occupancy, cells were incubated with or without exogenous BAFF before assessing anti-BAFF reactivity and changes in median fluorescence intensity (ΔMFI; defined by dividing the MFI of the anti-BAFF antibody by the MFI of the isotype matched control antibody) were calculated. Normal B cells have higher detectable levels of bound BAFF with a ΔMFI ranging from 16 to 35 (mean=22.2). Upon addition of exogenous BAFF, the ΔMFI range increased to 27–96.6 (mean=49.1; n=8). Thus, despite evidence of prebound BAFF, clearly not all BBRs were occupied on normal PB B cells. By contrast, the levels of prebound BAFF on CLL B cells were significantly lower with a ΔMFI ranging from 1 to 13.1 (mean=2.7; n=36). Of note, 10/36 patients did not exhibit increased anti-BAFF reactivity upon incubation with exogenous BAFF (mean fold induction=0.8) whereas 26/36 patients displayed a mean fold induction of anti-BAFF reactivity of 3.5. These observations prompted us to next quantitate CLL B cell BBR expression. All patient CLL B cells expressed BAFF-R but at significantly lower levels than observed in normal B cells (p=0.0009). When CLL patients were categorized into IGHV mutated (M; n=22) and unmutated (UM; n=24), UM patients were observed to express higher levels of BAFF-R (ΔMFI =8.9) than M patients (ΔMFI =5.24). Regarding TACI, we previously demonstrated that normal memory B cells uniformly express TACI (ΔMFI =12.7; n=10) and there is a small population of activated naïve B cells that express TACI at lower levels (ΔMFI =8.3; n=10). In our CLL cohort, 14/22 M patients were TACI+ (ΔMFI =7.0) and 19/24 UM patients were TACI+ (ΔMFI =4.7). Finally, whereas normal PB B cells completely lack BCMA expression, 7/22 M and 4/22 UM patients expressed BCMA. Thus, using the BBR profile and analysis of expression levels relative to normal PB B cells, the following subgroups of B-CLL can be defined: BAFF-R+; BAFF-R/TACI+; BAFF-R/BCMA+; BAFF-R/TACI/BCMA+. It remains to be determined if these BBR profiles correlate with aspects of clinical disease. In addition, given the putative importance of BAFF in this disease, it is interesting to note that in general, CLL B cells display overall lower levels of prebound BAFF. Current studies are focused on determining whether this reflects CLL B cell activation status, increased competition for BAFF, and/or reduced levels of BBR expression.

scholarly journals Changes in Glycanic Determinants of Lymphocytes Membranes in Peripheral Blood in Patients with B-Cell Chronic Lymphocytic Leukemia under Antitumor Therapy

2021 ◽  
Vol 6 (6) ◽  
pp. 141-147
Author(s):  
G. S. Maslak ◽  
◽  
G. P. Chernenko ◽  
V. M. Baibakov ◽  
A. D. Viselko ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Peripheral Blood ◽  
Peripheral Blood Lymphocytes ◽  
Lymphocytic Leukemia ◽  
Cytostatic Therapy ◽  
Tn Antigen ◽  
Antitumor Therapy ◽  
Blood Lymphocytes ◽  
Cell Chronic Lymphocytic Leukemia

The purpose of the study was to study the nature of changes in the exposure of surface glycans of peripheral blood lymphocytes in patients with B-cell chronic lymphocytic leukemia under conditions of antitumor therapy. Materials and methods. We studied the features of exposure of surface glycotopes of peripheral blood lymphocytes in patients with B-cell chronic lymphocytic leukemia under conditions of antitumor therapy using a set of seven lectins labeled with FITC and monoclonal antibodies to Tn-antigen- FITC for the detection of Tn antigen and CD43 exposure on blood lymphocytes. Cytostatic therapy included cyclophosphamide, vincristine (oncovin), prednisolone. Data were recorded on a Beckman Coulter EPICS flow cytometer. The results were processed using FCS3 Express. Results and discussion. The number of lymphocytes of healthy donors with a positive reaction to ConA, PHA-L, SNA, MAA-II and α1-acid glycoprotein amounted to 16.0±3.0%, 23.0±2.3%, 15.0±1.5%, 25.0±1.8% and 15.0±1.3%, respectively. The number of LABA-, UEA I-positive lymphocytes was 0.90±0.03% and 2.9±0.2%, respectively, and there was no binding to antibodies to Tn- and CD43-antigens. In the blood of patients with chronic lymphocytic leukemia, the level of ConA-, SNA- and MAA-II-positive lymphocytes increased relative to control by 2.2, 3.7 and 2.6 times, respectively. The number of LABA- and UEA I-positive lymphocytes in patients with chronic lymphocytic leukemia increased by 11 (p <0.01) and 23 (p <0.001) times and amounted to 10.5±0.5% and 67.5±5.5% respectively. The number of lymphocytes with CD43 antigen on their surface increased by 72 times, and the Tn antigen increased by 80 times. Cytostatic therapy reduced the level of LABA- and UEA I-positive lymphocytes by almost half, and MAA II-positive cells and lymphocytes interacting with antibodies to CD43 and Tn antigen by a third. The level of PHA-L-positive lymphocytes in the blood of chronic lymphocytic leukemia patients after undergoing alkylating therapy increased by 18.0±2.0% and almost did not differ from those obtained in the control group. Conclusion. 1. In chronic lymphocytic leukemia patients, the structure of glycoconjugates in peripheral blood lymphocytes changes, manifested in increased exposure of L-fucose, α-mannose and N-acetylneuraminic acid, which is confirmed by a significant increase in relation to the control of the number of ConA-, SNA-, MAA-II-, LABA I-positive cells. 2. Patients with chronic lymphocytic leukemia showed a significant increase in the number of lymphocytes, in which the markers of carcinogenesis CD43 and Tn antigens were found. 3. Cytostatic therapy significantly reduced the level of LABA-, UEA I- and MAA II-positive cells, as well as partially Tn- and CD43-antigen-positive lymphocytes, which indicates its positive effect on the treatment of chronic lymphocytic leukemia

Clinical relevance of intracellular vascular endothelial growth factor levels in B-cell chronic lymphocytic leukemia

Blood ◽  
2000 ◽  
Vol 96 (2) ◽  
pp. 768-770 ◽  
Author(s):  
Alvaro Aguayo ◽  
Susan O'Brien ◽  
Michael Keating ◽  
Taghi Manshouri ◽  
Cristi Gidel ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Lymphocytic Leukemia ◽  
Vascular Endothelial ◽  
Early Stage Disease ◽  
Normal Peripheral Blood ◽  
Endothelial Growth Factor ◽  
Cell Chronic Lymphocytic Leukemia

Abstract Strong evidence exists for an association between high vascular endothelial growth factor (VEGF) levels and poor prognoses in patients with solid tumors and acute leukemia. Using Western blot analysis and solid-phase radioimmunoassay, we measured cellular VEGF levels in B-cell chronic lymphocytic leukemia (CLL) samples from 225 patients and correlated these levels with disease characteristics and prognoses. The median VEGF level in CLL samples was 7.26 times the median level detected in normal peripheral blood mononuclear cells. Patients with lower levels of VEGF protein showed a trend toward shorter survival (P = .07). However, in a subgroup of CLL patients with good prognoses or early-stage disease (Rai stages 0-II, Binet stages A,B; β2-M ≤ 2.8 mg/dL), lower levels of VEGF were associated with shorter survival times. For the entire group of patients, no correlation was found between VEGF levels and β2-M levels or Rai and Binet stage. Most samples from patients with CLL expressed the 43-kd VEGF isoform in addition to the commonly expressed 45-kd isoform. It remains to be seen whether the expression of the 43-kd isoform is responsible for this reversed correlation with outcome.

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