A 57-gene expression signature in B-cell chronic lymphocytic leukemia

B-CLL is the most frequent type of leukemia in the Western countries. The disease, common among the elderly, follows a variable course in terms of survival time and symptoms. There is evidence that the accumulation of lymphocytes in peripheral blood and bone marrow is due to a cell resistance to apoptosis rather than to highly proliferative cells. Genetic mechanisms that lead to the development and progression of disease are mainly unknown, although a number of prognostically and diagnostically important genetic markers have been identified.     

CD23 antigen regulation and signaling in chronic lymphocytic leukemia.

B lymphocytes from patients with chronic lymphocytic leukemia (B-CLLs), strongly express the CD23 antigen, a surface marker with significant prognostic importance in this disease. Because we previously reported that IL-4 shows a poor capacity for CD23 expression on B-CLLs, we first examined the possible mechanisms underlying CD23 overexpression on B-CLLs and found that mitogen-activated CLL T cells release soluble factors that are capable, in synergy with IL-4, of strongly inducing CD23. Using neutralizing Abs, we noticed that the T-cell-derived enhancing activity is entirely ascribed to the combined effects of IFN gamma (potent inhibitor of CD23 on normal B cells), TNF alpha (which has no effect on normal B cells), and IL-2 (which has a slight enhancing effect on both CLL and normal B cells). Furthermore, recombinant IFN gamma as well as IFN alpha, TNF alpha, and IL-2 (but not IL-3, IL-5, IL-6, IL-7, and lymphotoxin) significantly enhance CD23 protein and mRNA expression on B-CLLs, in the presence or absence of IL-4. Inasmuch as optimal CD23 expression absolutely requires the combination of IFN gamma, IL-2, TNF alpha (the production of which is increased in CLL disease), and IL-4, it was relevant to show that IL-4 mRNA is indeed expressed in fresh T-CLL cells. We next examined the possible role of CD23 in the regulation of B-CLL proliferation. Signaling through CD23 via ligation of the antigen by F(ab')2 anti-CD23 MAb but not Fab fragments inhibits the cytokine-induced B-CLL DNA synthesis. It is concluded that the CD23 gene is abnormally regulated in B-CLL disease and that cross-linking of CD23 molecule delivers a negative growth signal to the leukemic B cells.     

Ecto-5'-nucleotidase in B-cell chronic lymphocytic leukemia.

Literature on the behaviour of ecto-5'-nucleotidase in the course of B-cell chronic lymphocytic leukemia is briefly reviewed and aims for further researches are highlighted.     

Anti-CD20 monoclonal antibodies in chronic lymphocytic leukemia

Introduction: The last decade has witnesd immense progress in the treatment of chronic lymphocytic leukemia (CLL). Chemoimmunotherapy (CIT) combining rituximab and fludarabine with cyclophosphamide (FCR) in the frontline setting has clearly been shown to improve outcomes in patients with CLL. Building on the success achieved with rituximab, other anti-CD20 monoclonal antibodies (mAbs) are being investigated. Novel bioengineering techniques have helped in the development of anti-CD20 mAbs. One antibody, ofatumumab, was recently approved for the treatment of refractory CLL. A type II anti-CD20 mAb, GA-101 (obinutuzumab), is currently in clinical trials. This short review focuses on ongoing clinical trials of anti-CD20 mAbs in CLL.

Areas covered: Literature search was performed using PubMed (www.clinicaltrials.gov (till August 2012)), and recent American Society of Clinical Oncology (ASCO), American Society of Hematology (ASH), European Hematology association (EHA), International workshop on CLL (iwCLL) abstracts, using the primary search terms ‘anti-CD20 monoclonal antibody' with/without CLL. Articles were chosen on the basis of relevance of anti-CD20 mAbs to CLL therapy.

Expert opinion: Rituximab, the prototype anti-CD20 mAb, forms the core of CIT in CLL. The success of rituximab and ofatumumab has led investigators to evaluate other anti-CD20 mAbs in the treatment of CLL.     

Comparative analysis of ZAP-70 expression and Ig VH mutational status in B-cell chronic lymphocytic leukemia

BACKGROUND: B-cell chronic lymphocytic leukemia (CLL) is a heterogeneous disorder with respect to its clinical course. Accurate identification of prognostic factors is becoming increasingly important in order to determine those patients requiring aggressive treatments. Two of the most predictive outcome markers are the Ig VH mutational gene status and ZAP-70 expression. In earlier reports, both parameters have shown a high degree of concordance. To assess the value of these determinations in clinical practice, we simultaneously analyzed Ig VH mutations and ZAP-70 expression in a consecutive series of B-CLL. METHODS: Fifty-three consecutive B-CLL cases were included in the study. ZAP-70 expression was investigated by flow cytometry. Positivity was established using two methods: comparing ZAP70 expression in B-cells with T-cells using cytoplasmic CD3 (ZAP-70/T) and with NK-cell reactivity (ZAP-70/NK). The complete immunophenotype was recorded in each case. Ig VH mutational gene status was determined employing purified RNA from peripheral blood samples. Retrotranscribed DNA was PCR-amplified, direct-sequenced, and compared with available public databases. VH3.21 family use was also recorded. RESULTS: Using a T-cell marker, 58% of patients were ZAP-70+ and 42% were ZAP-70-. NK-cell comparisons gave only 6% of ZAP-70 positivity in B-CLL, and in six cases the absence of a clearly defined NK-cell population precluded the ZAP70 analysis. Twenty-four (45%) patients had mutated Ig VH genes and 29 (55%) had unmutated Ig VH genes. The results showed a statistical association between ZAP-70/T expression and VH mutational status. Despite this, in 30% of cases there was a discordant result.Immunophenotypic analysis showed no major differences in Matutes'score between mutated and nonmutated cases. Only FMC7 was more commonly expressed in the unmutated B-CLL cases. VH3.21 was present in 7.5% of cases, mostly having an unmutated pattern. CONCLUSIONS: ZAP-70 reactivity using a T-cell marker as a control allows to identify the majority of patients with an unmutated Ig VH genotype. Parallel analysis revealed that discordances with Ig VH analysis are quite common with currently employed flow cytometry reagents and techniques.     

Absolute CD4 and CD8 counts and CD4-to-CD8 ratios in eight patients with indolent B-cell chronic lymphocytic leukemia

BACKGROUND: There are some patients with B-cell chronic lymphocytic leukemia who exhibit an extraordinary natural resistance to this malignancy, which lasts for many years. In this study, we report the T-cell subset values and ratios in eight such patients. METHODS: Impath (New York, NY) evaluated immunophenotyping by performing flow cytometry. Absolute CD4 and CD8 counts and CD4:CD8 ratios were performed at Memphis Pathology Laboratory, Memphis, Tennessee. RESULTS: CD4 and CD8 counts and CD4:CD8 ratios were normal in all eight patients, in contrast to the suppressor cell proliferation and low helper-suppressor ratios that have been previously reported in other patients with B-cell chronic lymphocytic leukemia. CONCLUSION: These results require further study to determine their significance. Implications for further study are discussed.     

Spontaneous remission of B-cell chronic lymphocytic leukemia associated with T lymphocytic hyperplasia in bone marrow

Spontaneous remissions in B-cell chronic lymphocytic leukemia (B-CLL) are rare and none of them has been studied with immunophenotyping (by flow cytometry and immunohistochemistry) and genotyping. In this patient, studied after spontaneous remission had occurred, there was a residual T-lymphocytic hyperplasia in the bone marrow with a normal CD4:CD8 ratio. Absolute CD4 and CD8 counts and CD4:CD8 ratio in the peripheral blood were normal. Flow cytometry revealed no B-CLL cells in the peripheral blood and less than 2% B-CLL cells in the bone marrow.     

低恶度非霍奇金淋巴瘤和慢性淋巴细胞白血病患者应用干扰素-α检测血清CD44的临床意义

目的通过观察血清CD44的变化评价干扰素-α（INF-α）治疗低恶度非霍奇金淋巴瘤（NHL）和慢性淋巴细胞白血病（CLL）的疗效。方法36例患者分为治疗组（26例）和观察组（10例），治疗组接受罗扰素（INFα-2α）300万单位每周3次皮下注射。观察组未用INFα-2α。两组患者在治疗开始前及每间隔4个月采集血清并冻存至标本收集完毕，使用ELISA的方法检测CD44的水平。结果观察组12例临床有效（4例完全缓解，8例部分缓解）；可溶性CD44水平12例患者表现出持续下降；在第4周和第8周时治疗组可溶性CD44水平高于观察组，差异有显著性意义（P=0.007、O．05），第12周时两组差异无显著性意义。结论血清CD44水平的检测可作为使用α-干扰素治疗疗效判断指标之一，在治疗12个月后如果CD44水平仍无下降应该考虑不再坚持使用α-干扰素治疗。     

分化抗原簇CD38在慢性淋巴细胞白血病T淋巴细胞中的表达研究

目的 探讨慢性淋巴细胞白血病(CLL)中T淋巴细胞CD38(CD38-T)的表达特征.方法 应用多参数流式细胞术检测83例CLL患者肿瘤细胞中CD38表达(CD38-B)、zeta链相关蛋白-70(ZAP-70)以及CD38-T、CD4/CD8比值的表达情况.结果 在所有患者中,CD38+-T占49.4%(41/83),CD38+-B占50.6%(42/83),CD38+-T和CD38-B表达有高度相关性(r=0.553,P<0.01);表达ZAP-70+CD38+-T和ZAP-70-CD38+-T的患者占67.5%(56/83),CD38-T与ZAP-70的表达有相关性(r=0.349,P<0.01).Binet A期患者中CD38+-T占33.3%(14/42),Binet B+C期患者中CD38+T占65.9%(27/41);XD38+-T与临床分期,CD4/CD8比例倒置有相关性(r=0.312、0.453,P<0.05).结论 CD38-T表达变化与患者病情进展及转归密切相关,CD38高表达的患者多伴有免疫功能调节紊乱或失衡,可作为CLL的一项全新独立的监测指标.     

The FcɛR2/CD23 antigen: A hallmark of chronic lymphocytic leukemia B cells

Summary The effect of different stimuli on the expression of the low-affinity receptor for the Fc fragment of IgE (FcɛR2/CD23) on peripheral blood B cells from patients with chronic lymphocytic leukemia (CLL) was investigated. CLL B cells cultured for 3 days in medium alone showed a progressive decrease of the FcɛR2/CD23 expression, while the addition to the cell cultures of IgE or interleukin-4 had a slackening effect on the decrease of the FcɛR2/CD23. In contrast, in the presence of interferon-γ the proportion of FcɛR2/CD23⁺ cells was more rapidly reduced compared to CLL B cells cultured in medium alone. Stimulation of CLL B cells withStaphylococcus aureus Cowan I (SAC) bacteria, which are able to enhance the expression of FcɛR2/CD23 on normal B cells, induced a rapid loss of the FcɛR2/CD23 from CLL B cells.     

Obinutuzumab for the treatment of chronic lymphocytic leukemia and other B-cell lymphoproliferative disorders

Introduction: Chemoimmunotherapeutic regimens using the anti-CD20 antibody rituximab improved significantly the survival rates in various B-cell lymphoproliferative disorders (LPDs), including chronic lymphocytic leukemia (CLL). The next-generation CD20 antibody obinutuzumab represents an addition to the drug armamentarium used for the therapeutic management of patients with LPDs.

Areas covered: Herein, the authors discuss the biochemical and conformational engineering of obinutuzumab to increase antibody-dependent cell-mediated cytotoxicity and direct cell death. They also describe the available preclinical data on obinutuzumab’s role in B-cell LPDs. Furthermore, the authors summarize the Phase I and II clinical trials of obinutuzumab, focusing on the main pharmacokinetic/pharmacodynamic characteristics, the most common clinically significant adverse events, dose optimization, and clinical outcomes of patients with CLL and other B-cell LPDs treated with obinutuzumab as monotherapy or in combination with other agents. To put these data in perspective, the use of obinutuzumab is compared with that of rituximab in CLL and other B-cell LPDs.

Expert opinion: Clinical trials have demonstrated that obinutuzumab is well tolerated. The novel mechanism of action of obinutuzumab is associated with significant efficacy in CLL and other B-cell LPDs. Ongoing clinical trials are expected to determine the optimal use of obinutuzumab in these diseases.