Chronic lymphocytic leukemia: present status

Chronic Lymphocytic Leukemia: A Review of Front-line Treatment Options, With a Focus on Elderly CLL Patients

Chronic lymphocytic leukemia (CLL) remains the most prevalent form of leukemia in the Western world, with no cure to date. Ongoing and essential research into this heterogeneous disease has led to a number of new treatment options becoming available to CLL patients in the past decade. The present review presents the recent developments in the field of CLL treatment, with the main focus on elderly patients and CLL patients with coexisting comorbidities. The review discusses the current treatment regimens that provide the most promising outcomes for patients in this subgroup, with a number of important clinical trials summarized. These clinical trials, which have investigated promising single-agent therapies or combination therapies, are discussed, with an emphasis on the efficacy and tolerability for patients aged ≥ 65 years. Also, the misrepresentation of the true CLL population in many clinical trials and the need for better guidelines for participant inclusion criteria to provide a more realistic and accurate study population are noted.

microRNA and Chronic Lymphocytic Leukemia

Expression profiling of microRNAs identified important differences in microRNA expression between CLL samples and normal CD5+ B-cells. Researchers have first discussed the dual role of miRNAs working as tumor suppressors (inhibiting malignant potential) or as oncogenes (activating malignant potential) in CLL pathogenesis. Understanding the roles of miRNAs in leukemic cells brings information on a new layer of gene regulation and also provides new markers for improved diagnosis and prognosis, as well as novel therapeutic options for CLL patients. Herein we will focus on the roles of miRNAs in CLL, highlighting what is already known about their function, proposing a novel model of CLL predisposition and progression, and describing the challenges for the near future.

Flow cytometry and polymerase chain reaction-based analyses of minimal residual disease in chronic lymphocytic leukemia

New therapeutic strategies developed recently for chronic lymphocytic leukemia (CLL) have led to remarkable treatment response rates and complete hematological remissions. This means highly sensitive and specific techniques are increasingly needed to evaluate minimal residual disease (MRD) in CLL patients. Quantitative MRD levels can be used as prognostic markers, where total MRD eradication is associated with prolonged survival. Nowadays, PCR and flow cytometry techniques used to detect MRD in CLL patients can generate reliable and quantitative results with the highest sensitivity. MRD Flow is based on four-color flow cytometry using specific antibody combinations. For allele specific oligonucleotide real-time quantification (ASO RQ) PCR individual primers are designed to detect a specific immunoglobulin heavy chain (IgH) rearrangement in each patient clone. Five comprehensive studies investigated and compared the sensitivity and specificity of both methods. Groups of patients receiving different therapies were analyzed at different time points to generate quantitative MRD levels and MRD kinetics. All studies confirmed that both methods generate equivalent results with regard to sensitivity and MRD quantification, although each method has advantages and disadvantages in the daily routine of a standard hematological laboratory. Here, we review these investigations and compare their results in the light of modern therapies.

Aberrant splicing of the E-cadherin transcript is a novel mechanism of gene silencing in chronic lymphocytic leukemia cells

Premature termination codon (PTC) mutations are due to insertion or deletion of nucleotides causing a frameshift and premature termination codon in RNA. These transcripts are degraded by the nonsense-mediated decay pathway and have a very short half-life. We used a microarray technique to screen for genes that up-regulate their RNA signal upon nonsense-mediated decay pathway blockade in chronic lymphocytic leukemia (CLL) specimens and identified an E-cadherin transcript with PTC. Sequencing revealed an aberrant E-cadherin transcript lacking exon 11, resulting in a frameshift and PTC. The aberrant E-cadherin transcript was also identified in normal B cells, but occurred at a much lower level compared with CLL cells. In CLL specimens, E-cadherin expression was depressed more than 50% in 62% cases (relative to normal B cells). By real-time polymerase chain reaction analysis, the relative amounts of wild-type transcript inversely correlated with amounts of aberrant transcript (P = .018). Ectopic expression of E-cadherin in CLL specimens containing high amounts of aberrant transcript resulted in down-regulation of the wnt-beta-catenin pathway reporter, a pathway known to be up-regulated in CLL. Our data point to a novel mechanism of E-cadherin gene inactivation, with CLL cells displaying a higher proportion of aberrant nonfunctional transcripts and resulting up-regulation of the wnt-beta-catenin pathway.

Assessment of expression of selected Bcl-2 family proteins in lymphoid infiltration in patients with B-cell chronic lymphocytic leukaemia treated with nucleoside analogues

B-cell chronic lymphocytic leukaemia (B-CLL) is characterized by clonal growth and accumulation of mature lymphoid cells due to disturbance in genetically regulated form of cell death called apoptosis. The intrinsic mechanism of apoptosis is controlled by Bcl-2 family proteins. Purine nucleoside analogues induce the apoptosis in cells in a state of quiescence. The aim of the study was to assess expression of selected Bcl-2 family proteins in neoplastic infiltration in bone marrow in patients with B-CLL treated with nucleoside analogues. The study comprised examination of bone marrow obtained routinely by trephine biopsy from 18 patients with B-CLL diagnosed before administration of purine nucleoside analogues treatment and after its completion. Expression of Bcl-2, Bcl-x and Bax proteins was examined. Lymphoid cells in bone marrow were present in all patients before administration of treatment. After treatment in two patients bone marrow was infiltrated in diffuse pattern, whereas other patients presented nodular pattern of infiltration. The difference between stage of infiltration before and after treatment was statistically significant (p<0.002). High percentage of infiltration cells with positive anti Bcl-2 reaction from 42.0% in one patient to 85.33+/-3.06% in four patients before treatment was observed. After treatment percentage of infiltration cells with positive anti Bcl-2 antibody reaction was from 33.0+/-18.38% in two patients to 99.0% in one patient. Positive correlation between stage of infiltration and expression of Bcl-2 protein was confirmed before and after treatment. Such correlations were not observed in case of Bax and Bcl-x. Strong staining of immunohistochemical reaction of cells in lymphoid infiltration with Bcl-2 antibody was confirmed. There was a difference between Bcl-/Bax ratio before and after treatment. Immunohistochemical assessment of expression of Bcl-2 family proteins in cells of lymphoid infiltration in bone marrow of patients with CLL is an important method in detection of minimal residual disease (MRD) after treatment.

Small RNAs analysis in CLL reveals a deregulation of miRNA expression and novel miRNA candidates of putative relevance in CLL pathogenesis

MicroRNAs (miRNAs) are a novel class of small noncoding RNA molecules that regulate gene expression by inducing degradation or translational inhibition of target mRNAs. There are more than 500 miRNA genes reported in the human genome, constituting one of the largest classes of regulatory genes. Increasing experimental evidence supports the idea of aberrant miRNA expression in cancer pathogenesis. We analyzed the pattern of miRNA expression in chronic lymphocytic leukemia (CLL) cells and our results showed a global reduction in miRNA expression levels in CLL cells associated to a consistent underexpression of miR-181a, let-7a and miR-30d. We observed overexpression of miR-155 and a set of five miRNAs that are differentially expressed between patients with different clinical outcomes. Five novel miRNA candidates cloned from leukemic cells are reported. Surprisingly, predicted mRNA targets for these novel miRNA revealed a high proportion of targets located in a small region of chromosome 1, which is frequently altered in human cancer. Additionally, several targets were shared by at least two of miRNA candidates. Predicted targets included several genes recently described as tumor suppressors. These data could afford new avenues for exploring innovative pathways in CLL biology and therapy.

Chronic lymphocytic leukemia radiogenicity: a systematic review

OBJECTIVE

Chronic lymphocytic leukemia (CLL) is generally considered to be non-radiogenic and is excluded from several programs that compensate workers for illnesses resulting from occupational exposures. Questions about whether this exclusion is justified prompted a Congressional mandate to the National Institute for Occupational Safety and Health (NIOSH) to, further, examine the radiogenicity of CLL. This study revisits the question of CLL radiogenicity by examining epidemiologic evidence from occupationally and medically-exposed populations.

METHODS

A systematic review of radiation-exposed cohorts was conducted to investigate the association between radiation and CLL. Exploratory power calculations for a pooled occupational study were performed to examine the feasibility of assessing CLL radiogenicity epidemiologically.

RESULTS

There is a bias against reporting CLL results, because of the disease's presumed non-radiogenicity. In medical cohort studies that provide risk estimates for CLL, risk is elevated, though non-significantly, in almost all studies with more than 15 years average follow-up. The results of occupational studies are less consistent.

CONCLUSIONS

Studies with adequate follow-up time and power are needed to better understand CLL radiogenicity. Power analyses show that a pooled study might detect risk on the order of radiation induced non-CLL leukemia, but is unlikely to detect smaller risks.

Trisomy 8 as sole cytogenetic abnormality in a case of chronic lymphocytic leukemia

A 49-year-old man, who had been diagnosed with chronic lymphocytic leukemia (CLL) in 2002, had a normal karyotype in his bone marrow. Trisomy 8 was demonstrated in his peripheral blood in 2005. Fluorescence in situ hybridization using an LSI CEP 8 probe performed on the archival bone marrow specimen showed three hybridization signals in 40% of 200 interphase cells scored. This confirmed that the trisomy 8 abnormality was present in both the blood and bone marrow samples. Trisomy 8 as the sole chromosomal abnormality in CLL is a very rare finding. The prognostic significance of trisomy 8 in CLL remains to be seen.

Korean patients with chronic lymphocytic leukemia show the similar types of chromosomal aberrations as those in Europe and North America

Chronic lymphocytic leukemia (CLL) is frequent in the West, but rare in Korea. In this study, the frequency of chromosome aberration in Korean CLL patients was examined by applying interphase fluorescence in situ hybridization (FISH). Conventional cytogenetic test and FISH were performed on bone marrow aspirates obtained from 16 CLL patients. By applying DNA probes (Vysis, Downers Grove, IL, USA), the deletion in 11q22-23, 13q14, 13q34, and 17p13, and trisomy 12 were examined. With FISH, molecular cytogenetic aberration was detected in 10 of 16 patients [63%, 95% confidence interval (CI) 39-86], whereas with conventional cytogenetic test, chromosomal aberration was detected only in 2 out of 13 cases (15%, 95% CI 0-35). In total, the cases with one or more chromosomal aberrations were 11 out of 16 cases (69%, 95% CI 46-92). The most frequently detected aberration was the 13q14 deletion (69%, 95% CI 44-94), followed by trisomy 12 (19%, 95% CI 0-38) and 11q22 deletion (14%, 95% CI 0-33). No deletion in 17p13 was observed. In conclusion, CLL in Korean is a heterogeneous genetic disorder, showing similar genetic changes in Europe and North America.

Chronic lymphocytic leukemia: A review of some new aspects of the biology, factors influencing prognosis and therapeutic options

This review provides some basic information on chronic lymphocytic leukemia (CLL) and attempts to present some of the newer data which have accumulated in recent years including those relating to familial aggregation of CLL and the detection of monoclonal CD5+ lymphocytosis in the general population and families of CLL patients. Novel data on the pathogenesis and concepts of cell origin in CLL are also reviewed stressing the fact that there is biased IgVH gene usage, and the importance of mutational status of the CLL cell, as reported in recent years by different authors. A brief review of the significance of the microenvironmental interactions between stromal cells and other accessory cells, and the leukemic CLL cells is also provided. Other clinical aspects are discussed including diagnostic criteria, clinical staging, and the newer prognostic factors which influence survival and timing of therapy for CLL patients. We also attempt to outline the therapeutic options available and the principles of planning risk and age-adapted treatment, stressing the importance and the necessity for participating in ongoing and future international clinical trials.

CXCR4 and SDF-1 expression in B-cell chronic lymphocytic leukemia and stage of the disease

The pathogenesis of B-cell chronic lymphocytic leukemia (B-CLL) has been linked to an overexpression of the chemokine receptor CXCR4 and increased in vitro functional response to its natural ligand CXCL12 (SDF-1). The CXCR4/SDF-1 system appears to be important for tissue localization and increased survival of B-CLL cells. The aim of our study was to examine if CXCR4 expression and SDF-1 blood levels were correlated to clinical and pathological stage of B-CLL. Flow cytometry and enzyme-linked immunosorbent assay (ELISA) techniques were used to determine CXCR4 expression and SDF-1 plasma levels, respectively, in a cohort of 51 patients diagnosed with B-CLL to correlate these measurements with several parameters that define the clinical stage of the disease. We confirmed that CXCR4 was consistently expressed on circulating B-CLL cells with a fluorescence intensity that was five-fold greater than in cells from healthy volunteers. There was a correlation between CXCR4 expression and leukocyte count ( r: 0.55, p<0.01), and CD19(+)/CD5(+ )cells ( r: 0.63, p<0.01). Interestingly, the group of B-CLL patients showed lower SDF-1 plasma levels compared to the control group. However, there was no correlation between CXCR4 or SDF-1 expression and the clinical stage of disease or the pattern of bone marrow infiltration. The results obtained suggest that other factors, and not only alteration in the SDF-1/CXCR4 chemokine system, must account for marrow infiltration of neoplastic cells observed in B-CLL and that CXCR4 could be involved in other features that exhibit malignant B cells, such as increased survival, rather than in their homing or migration to the bone marrow.

B-chronic lymphocytic leukemia: practical aspects

B-CLL is the most common adult leukemia in the Western world. It is a neoplasia of mature looking B-monoclonal lymphocytes co-expressing the CD5 antigen (involving the blood, the bone marrow, the lymph nodes and related organs). Much new information about the nature of the neoplastic cells, including chromosomal and molecular changes as well as mechanisms participating in the survival of the leukemic clone have been published recently, in an attempt to elucidate the biology of the disease and identify prognostic subgroups. For the time being, clinical stage based on Rai and Binet staging systems remains the strongest predictor of prognosis and patients' survival, and therefore it affects treatment decisions. In the early stages treatment may be delayed until progression. When treatment is necessary according to well-established criteria, there are nowadays many different options. Chlorambucil has been the standard regimen for many years. During the last decade novel modalities have been tried with the emphasis on fludarabine and 2-chlorodeoxyadenosine and their combinations with other drugs. Such an approach offers greater probability of a durable complete remission but no effect on overall survival has been clearly proven so far. Other modalities, included in the therapeutic armamentarium, are monoclonal antibodies, stem cell transplantation (autologous or allogeneic) and new experimental drugs. Supportive care is an important part of patient management and it involves restoring hypogammaglobulinemia and disease-related anemia by polyvalent immunoglobulin administration and erythropoietin respectively.

Campath-1H (anti-CD52) monoclonal antibody therapy in lymphoproliferative disorders

Campath-1H is a humanized monoclonal antibody targeted against the CDw52 membrane antigen of lymphocytes, which causes complement and antibody-dependent cell-mediated cytotoxicity. Campath-1H has been used in B-chronic lymphocytic leukemia (B-CLL), T-prolymphocytic leukemia (T-PLL), and low-grade non-Hodgkin's lymphoma (LGNHL). Campath-1H is administered intravenously thrice weekly for up to 12 wk, at an initial dose of 3 mg, escalated to 10 and 30 mg. The responses (complete [CR] and partial [PR]) obtained in untreated B-CLL patients are of the order of 90%. In previously treated B-CLL patients, responses are of the order of approximately 40%, with 2-4% CRs. Responses are more prominent in the blood and bone marrow compared to the lymph nodes. The median duration of response is 9-12 mo. Because of the antibody's higher activity on circulating lymphocytes, it has been used for in vivo purging of residual disease in B-CLL, followed by autologous stem-cell transplantation. In heavily pretreated advanced stage LGNHL, response is achieved only in 14% of cases with B-phenotype; a 50% response rate is noted in mycosis fungoides. In T-PLL, the CR rate is approximately 60%. Promising results have been reported in a small number of patients with refractory autoimmune thrombocytopenia of lymphoproliferative disorders. The main complications of Campath-1H treatment are caused by tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 release, usually during the first intravenous infusion, and include fever, rigor, nausea, vomiting, and hypotension responsive to steroids. These side effects are usually less severe with subsequent infusions and can be prevented by paracetamol and antihistamines. Immunosupression resulting from normal B- and T-lymphocyte depletion is frequent, resulting in an increased risk for opportunistic infections. More clinical trials in a larger number of patients are necessary to determine the exact role and indications of Campath-1H in lymphoproliferative disorders.

Disruption of the IFN-gamma cytokine network in chronic lymphocytic leukemia contributes to resistance of leukemic B cells to apoptosis

Recent evidence indicates that the slowly expanding population of CD5+ B cells that characterizes chronic lymphocytic leukemia (CLL) results primarily from defects in responses to cytokines that regulate apoptosis (e.g. I1-4, TGF-beta, IFN-alpha, IFN-gamma). We have now demonstrated not only that the enhanced anti-apoptotic effect of IFN-gamma on these neoplastic B cells is apparently mediated through increased levels of IFN-gamma receptors but also that there are increased numbers of IFN-gamma-expressing CD4 and CD8 T cells in these patients. This is the strongest evidence to date that multiple alterations in the IFN-gamma cytokine network contribute to the pathogenesis of CLL.

Ex vivo assessment of drug response by differential staining cytotoxicity (DiSC) assay suggests a biological basis for equality of chemotherapy irrespective of age for patients with chronic lymphocytic leukaemia

With a mean age at diagnosis for chronic lymphocytic leukaemia (CLL) of 65 years, development of optimal therapeutic regimens has been hampered by the advanced age of patients. In general, because of comorbidity older patients are not treated with the intent of achieving a complete response and so do not attain the quality of response of younger patients and do not survive as long. We have investigated whether or not ex vivo cellular sensitivity to cytotoxic drugs could be an underlying biological basis for this age differential in response and survival by comparing ex vivo drug response with age in untreated CLL patients. Cells from 365 untreated CLL patients aged 31.1-87.1 years (average 65.3 years) were tested for drug response by differential staining cytotoxicity (DiSC) assay with a panel of 10 drugs. An average of 280 results (range 196-361) obtained for each drug was compared with patient age. For chlorambucil, cyclophosphamide, prednisolone, vincristine, doxorubicin, epirubicin, fludarabine, cladribine and methylprednisolone, no relationship was found between ex vivo drug response and age (r<0.12). For pentostatin, a possible but very weak relationship (r = 0.18; n = 210; P = 0.06) was found. We conclude that cellular sensitivity to cytotoxic drugs does not support the differential treatment of older and younger CLL patients.

Campath-1H in B-chronic lymphocytic leukemia: report on a patient treated thrice in a 3 year period

Monoclonal antibody (mAb) therapy is a novel alternative treatment for lymphoid malignancies. In this report we present a 55-year-old patient with B-chronic lymphocytic leukemia, who was initially treated with chlorambucil p.o. and subsequently with cyclophosphamide iv with poor response. Then Campath-1H mAb was administered. He received three cycles of Campath-1H, over a 3 yr period, lasting 12 weeks each, at a final dose of 30 mg weekly, on an outpatient basis. After each cycle of Campath-1H administration there was a significant decrease of the size of the palpable lymph nodes, spleen and liver. Restoration of the blood lymphocyte count to normal and a significant decrease of the bone marrow lymphocytic infiltration was observed at the end of each cycle. Therefore, a major clinical response was obtained after all cycles. Campath-1H administration was well tolerated without causing any serious toxicity.

Serum levels of tetranectin, intercellular adhesion molecule-1 and interleukin-10 in B-chronic lymphocytic leukemia

BACKGROUND AND OBJECTIVE

The fibrinolytic regulator tetranectin (TN), in association with the circulating intercellular adhesive molecule-1 (cICAM-1) and interleukin -10 (IL-10), may be involved in the metastatic cascade of B-chronic lymphocytic leukemia (B-CLL). Our aim was to investigate the potential usefulness of these molecules as prognostic markers in B-CLL.

DESIGN AND METHODS

Therefore, TN, cICAM-1, and IL-10 were assessed (ELISA) in the serum of 53 B-CLL patients, classified in Binet A, B, and C stages in comparison with those in 45 healthy subjects (HS).

RESULTS

TN was significantly lower in B-CLL patients than in HS (9.63 [8.75-11.51] mg/L, 13.75 [12.56-14.64] ng/mL, respectively, p<10(-5)), being lower (p = 0.05) in B and C stage patients (subgroup B+C) than in A stage ones (subgroup A). cICAM-1 levels were significantly higher in B-CLL patients than in HS (475.86 [355.86-593.79] ng/mL vs. 225.62 [118.49-312.83] ng/mL, respectively, p<10(-5)) with a tendency for higher levels in subgroup B+C than in subgroup A. A significant correlation of cICAM-1 with lactate dehydrogenase (LDH) (r(s) = 0.532, p = 0.049), and a significant increase in cICAM-1 in B-CLL with diffuse bone marrow infiltration (BMI) compared to that in B-CLL with nondiffuse BMI (624.48 [557.24-726.55] ng/mL vs. 480.34 [368.96-590.34] ng/mL, respectively, p = 0.0172) were found. A significant negative correlation between TN and cICAM-1 (r = -0.5017, p = 0.0001) was observed. IL-10 was detected in all B-CLL patients and in no HS (7.37 [5.30-10.55] pg/mL), being higher (p = 0.0153) in C than in A stage patients. A significant correlation of IL-10 with TN and cICAM-1 in subgroup B+C (r(s) = -0.659 [p = 0.014] and r = 0.679 [p = 0.011], respectively) was found.

CONCLUSIONS

The abovementioned findings and good performance characteristics of TN and cICAM-1 in B-CLL suggest the potential usefulness of these adhesive/recognition molecules as prognostic markers in B-CLL. The implication of these molecules along with IL-10 in the disease process deserves further study.

Fludarabine and epirubicin in the treatment of chronic lymphocytic leukaemia: a German multicenter phase II study

PURPOSE

Fludarabine has been reported to be the most effective single-agent in previously treated chronic lymphocytic leukaemia (CLL). Based on the in vitro synergism of fludarabine with anthracyclines and on results showing a higher efficacy of CHOP against COP we attempted to improve treatment results with a combination of fludarabine and an anthracycline.

PATIENTS AND METHODS

The aim of the multicenter study was to evaluate the rate and duration of remissions and investigate the toxic and immunosuppressive effects of fludarabine and epirubicin in the treatment of CLL in Binet stages B and C as first-line therapy or in first relapse. Thirty-eight patients were treated with fludarabine 25 mg/m2 on days 1-5 and epirubicin 25 mg/m2 on days 4 and 5.

RESULTS

The overall response rate (OR) was 82% (95% confidence interval (95% CI): 66%-92%) with a CR rate of 32% (95% CI: 18%-49%). For the 25 previously untreated patients the OR was 92% (95% CI: 74%-99%) including 40% CRs (95% CI: 21%-61%). Granulocytopenia grade 3 occurred in 23% of all evaluable cycles, and grade 4 in 17%. The median remission duration was 19 months (range 6-37 months).

CONCLUSION

The results show that the combination of fludarabine and epirubicin is tolerable and highly effective in the treatment of CLL. With the addition of epirubicin to fludarabine, it appears possible to achieve a higher response rate and a more rapid response, especially of nodal manifestations. This regimen can be administered in an outpatient facility except for the first cycle because of the risk of a tumour lysis. The possible benefit of the combination presented here in the treatment of CLL in comparison to single-agent fludarabine treatment is presently under study in a prospective randomized multicenter study.

Clinical resistance to topoisomerase-targeted drugs

This review describes topoisomerase (topo)-mediated drug resistance and topo expression in human tissues and cancers. In some in vitro studies a relation has been observed between topo I, IIalpha or IIbeta expression and sensitivity to topo inhibitors. Drug resistance to topo inhibitors may, however, be multifactorial. Several topo inhibitors are substrates for drug membrane transporters. As most topo inhibitors are cell cycle specific, disturbances in cell cycle regulation can also confer resistance, and downstream events following DNA damage induced by topo inhibitors may be involved in regulating cell death or survival. Several studies in patient specimens have shown a relation between topo IIalpha expression and the proliferative state of the tumor, higher topo IIalpha levels being seen in more highly proliferating tumor types. In contrast, topo IIbeta appears to be expressed in both proliferating and quiescent cells. Furthermore, higher topo I levels were observed in some tumors when compared to their normal counterparts. In some studies a reduced topo IIalpha level was seen in samples taken after chemotherapy treatment, as compared with specimens prior to treatment. No unequivocal relation was observed, however, between expression or activity of the topo genes and response to chemotherapy; nonetheless only a few studies have properly addressed this question. This review summarizes the results of the clinical studies performed so far, and analyzes the critical issues in performing studies on patient material.

CD5 negative B-cell chronic lymphocytic leukemia: clinical and biological features of 42 cases

Chronic lymphocytic leukemia cell (CLL) usually (95%) express B-phenotype and the CD5 antigen which is usually present on the surface of normal T cells. However, among B CLL, 7 to 20% do not express CD5. The significance of the lack of CD5 expression remains unclear. We reviewed 42 consecutive CD5- B CLL seen in three French medical centers from 1985 to 1991 and compared them with 79 CD5+ B CLL. Immunophenotype studies were performed using indirect immunofluorescence under light microscopy as well as flow cytometry after 1988. B CLL was considered to be CD5 negative when less than 5% of mononuclear cells expressed CD5 after subtraction of the number of T-cells. Cases with CD5- B CLL had isolated splenomegaly more frequently (p = 2.10(-7)). They frequently expressed a higher level of surface immunoglobulin (S-Ig) or the switch mu/delta phenotype (p = 4.7 10(-2)). The median survival time was not reached but no significant difference between CD5 negative and positive B CLL was observed at the time of our data analysis (p = 0.97). Clinical presentation of CD5- B CLL seems to be different from other forms of B CLL. Although, no conclusion can be reached in terms of prognosis, CLL with low expression of CD5 should be regarded as a subtype of CLL with a different clinical presentation than CD5+ CLL.

Trisomy 12 in chronic lymphocytic leukemia--geographical variation

Incidence of trisomy 12 was studied in 60 cases of chronic lymphocytic leukemia (CLL) with chromosome 12 specific alpha-satellite DNA probe by fluorescence in situ hybridization (FISH). Trisomy 12 was observed in 37 (61.8%) patients. Cells with trisomy 12 were detected in a varying proportion, ranging from > 2% to 86%. Patients with trisomy 12 were predominantly observed with total white blood cell (WBC) count > 80 x 10(9) l(-1) (P < 0.001). In addition, the percentage of trisomy 12 positive lymphocytes correlated with the high WBC counts. Trisomy 12 was observed equally in typical and atypical CLL. 90% of our patients were in the intermediate and high risk groups. It was seen that there was significantly higher percentage of trisomy 12 positive lymphocytes ( > 10%) in the high risk groups (P < 0.05). A higher incidence of FMC7 positivity in atypical CLL was seen in our study. However, there was no significant relationship found between trisomy 12 positivity and expression of either FMC7 or CD23 in our cases. It appears that the CLL that we see at our centre is at a different phase of evolution and perhaps biologically different compared to the CLL seen in the West.

Hematopoietic stem cell transplantation in chronic lymphocytic leukemia: a report of 12 patients from a single institution

BACKGROUND

Stem-cell transplantation is a reasonable therapeutic approach for younger patients with high-risk CLL.

PATIENTS AND METHODS

Twelve patients (seven males; median age 47 years, range 29-51) with high-risk CLL underwent transplantation (allo, n = 7; auto, n = 5). The conditioning regimen consisted of cyclophosphamide and total body irradiation in 11 patients, and BEAC in the remaining one. Minimal residual disease (MRD) was assessed by cytofluorometry and PCR.

RESULTS

All 11 evaluable patients engrafted. Of the seven allografted patients, two died of treatment-related causes; three patients developed acute GVHD. No transplant-related mortality was observed in autografted patients. After transplantation, 10 of 11 patients evaluable for response achieved CR (91%; 95% CI 59%-100%) which was molecular in nine patients (82%; 95% CI 48%-98%). One patient in CR but MRD+ relapsed nine months after transplantation and died. Seven patients remain in molecular CR for a median of 16 months (range 1-58). Estimated actuarial survival and disease-free survival at two years is 81% (95% CI 43%-100%) and 71% (95% CI 43%-99%), respectively. Relapse risk at two years is 12.5% (95% CI 0%-35.5%).

CONCLUSIONS

Patients with high-risk CLL can achieve long-lasting molecular CR after SCT. The role of transplants in CLL management deserves investigation in controlled trials.

The pathologic significance of the immunoglobulins expressed by chronic lymphocytic leukemia B-cells in the development of autoimmune hemolytic anemia

The increased number of CD5+ B-cells in some human autoimmune diseases, the frequent commitment of CD5+ B-cells to the production of natural autoantibodies, and the apparent involvement of these cells in the pathogenesis of the autoimmune hemolytic anemia (AIHA) in certain mouse models suggests a causal relationship between the CD5+ chronic lymphocytic leukemia (CLL) B-cell and the AIHA which frequently develops in this malignant disorder. In support of this conclusion is our recent finding that the VH region gene repertoire of the leukemic B-cells from CLL patients with AIHA is rather biased and characterised by the over-representation of the 51p1 VH gene. On the other hand, it appears relatively certain that the pathogenic anti-erythrocyte antibodies in CLL patients with AIHA are produced by remnant normal B-cells, and that the antibodies expressed by the leukemic CD5+ B-cells do not directly bind red blood cells (RBC). Of interest, the antibodies produced by the leukemic B-cells from CLL patients with AIHA might have in common rheumatoid factor (RF) activity. These data indicate that the antibodies produced by the leukemic B-cells from CLL patients with AIHA are not directly involved in red blood cell destruction, but may be involved in the induction or amplification of a polyclonal anti-RBC response. Finally, we discuss the possible clinical implications of our finding that CLL patients with leukemic cells expressing the 51p1 VH gene may be at a higher risk to develop autoimmune hemolytic anemia.

Mitoxantrone, a topoisomerase II inhibitor, induces apoptosis of B-chronic lymphocytic leukaemia cells

B-chronic lymphocytic leukaemia (B-CLL) is characterized by the accumulation of long-lived CD5+ B lymphocytes. The effect of mitoxantrone, a topoisomerase II inhibitor, on B-CLL cells was studied. Treatment of B-CLL cells for 48 h with mitoxantrone (0.5 microg/ml) induced a decrease in cell viability as determined by MTT assay. The IC50 calculated for the cells of three patients was 0.7 microg/ml for two of them and 1.4 microg/ml for the third. In all three patients the maximum effect was observed with 2 microg/ml. An additive cytotoxic effect was observed when mitoxantrone (0.5 microg/ml) was combined with fludarabine (5 microg/ml). Mitoxantrone induced DNA fragmentation and the proteolytic cleavage of poly(ADP-ribose) polymerase (PARP), a marker of the activation of caspases, in all the patients studied, demonstrating that the cytotoxic effect of mitoxantrone was due to induction of apoptosis. These results suggest that mitoxantrone, and possibly other topoisomerase II inhibitors, may be used in the chemotherapy of B-CLL, and that combination of mitoxantrone with fludarabine or other drugs could improve the effectiveness of the treatment.

Elevated levels of biologically active soluble CD40 ligand in the serum of patients with chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is an indolent lymphoproliferative disorder manifested by low growth fraction and prolonged survival of the malignant cells. The mechanisms that enable CLL cells to live longer and to resist apoptosis remain unclear. Because the malignant CLL cells express CD40 and Fas receptors, which can transduce cell-survival and cell-death signals, we examined the role of CD40 in the growth regulation of CLL cells and its interaction with Fas-mediated and fludarabine-induced apoptosis in vitro. Primary CLL cells underwent spontaneous apoptosis in culture, which was enhanced by exogenous human Fas ligand (FasL) or fludarabine. Exogenous CD40L rescued CLL cells from spontaneous apoptosis in a dose-dependent manner, and caused CLL cells to resist apoptosis induced by FasL or fludarabine. Patients' autologous plasma rescued CLL cells from spontaneous apoptosis, an effect that could be reversed with anti-CD40 ligand (CD40L) antibodies. The levels of soluble CD40 ligand in the sera of 51 CLL patients and 55 healthy donors were determined by enzyme-linked immunosorbent assay. The mean soluble CD40L level in normal donors was 0.29 ng/ml compared to a mean value of 0.80 ng/ml in CLL patients (P < 0.001). CD40L up-regulated bcl-X(L) mRNA but not bcl-2 in CLL cells within 3-6 h in culture. Our results demonstrated that serum of patients with CLL contained elevated levels of biologically active soluble CD40L, and that CD40L can prolong survival of CLL cells and mediate their resistance to FasL and fludarabine in vitro.

Altered response to and production of TGF-beta by B cells from autoimmune NZB mice

New Zealand Black (NZB) mice spontaneously develop immune dysfunction manifested as autoimmune hemolytic anemia and systemic lupus erythematosus. In later life, a subset of these mice develop clonal CD5+ B cell tumors analogous to human chronic lymphocytic leukemia (CLL). NZB disease is marked by B cell hyperactivity characterized by spontaneous immunoglobulin secretion and proliferation. Elimination of autoreactive lymphocytes by apoptosis is a vital mechanism to prevent expansion of self-reactive lymphocyte population. TGF-beta appears to be an important factor in normal and abnormal immune regulation and this cytokine may play a role in the development of chronic human B cell tumors. We asked whether the response to or production of TGF-beta by NZB B cells was aberrant and could contribute to disease development. In this study, we demonstrated that the apoptotic response to TGF-beta was increased in B cells from NZB mice compared to B cells from normal BALB/c mice. The increased apoptosis was related to endogenous activation and was possibly mediated through increased expression of the TGF-beta Type II receptor. Despite functional differences between CD5-negative B cells and CD5-positive B cells, TGF-beta induced apoptosis in both populations to a similar extent. NZB B cells also secrete increased active TGF-beta compared to BALB/c B cells. We suggest that the aberrant secretion of active TGF-beta and the increased response to the apoptotic effects of TGF-beta by NZB B cells may play a role in the disease process of these mice, perhaps attempting to limit the autoimmune phenomena, but possibly also contributing to generalized immunosuppression. We also suggest that the CD5(+) tumors in the NZB mouse may not be a fully appropriate model of human CLL, since CLL B cells are abnormally resistant to the apoptotic effects of TGF-beta.

Involvement of CED-3/ICE Proteases in the Apoptosis of B-Chronic Lymphocytic Leukemia Cells

B-chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of long-lived B lymphocytes that express high levels of Bcl-2. We examined the involvement of CED-3/ICE-like proteases in the apoptosis of B-CLL cells. One of the substrates of these proteases is poly(ADP [adenosine 5′-diphosphate]-ribose) polymerase (PARP). The effect of different factors that induce the apoptosis of B-CLL cells on the proteolytic cleavage of PARP has been studied. Treatment of B-CLL cells with different concentrations of dexamethasone (1 to 1,000 μmol/L) induced in a dose-dependent manner the cleavage of PARP. Dexamethasone induced PARP cleavage after 12 hours of incubation, which was almost complete at 48 hours. PARP cleavage during apoptosis of B-CLL cells was studied in cells from eight patients and a correlation was found between cell viability and the degree of PARP cleavage. Incubation in vitro of B-CLL cells with fludarabine for 48 hours induced PARP cleavage in all the cases studied. Protein kinase C (PKC) activation with 100 nmol/L TPA (12-O-tetradecanoylphorbol 13-acetate) or incubation with interleukin-4 (10 ng/mL) prevented either dexamethasone- or fludarabine-induced proteolysis of PARP. Incubation of B-CLL cells with the CED-3/ICE–like protease inhibitor Z-VAD.fmk inhibited spontaneous and dexamethasone-induced PARP cleavage and DNA fragmentation in a dose-dependent manner. Furthermore, Z-VAD.fmk prevented the cytotoxic effect of dexamethasone. These results indicate that CED-3/ICE–like proteases play an important role in the apoptosis of B-CLL cells.

Chronic lymphocytic leukemia of B-cell origin: oral manifestations and dental treatment planning

Chronic lymphocytic leukemia, or CLL, is the most common form of leukemia in the Western Hemisphere, accounting for approximately 30 percent of all cases. With patients having an expected life span of more than seven years, CLL is a relatively indolent hematologic malignant disease that, while incurable, often has a prognosis compatible with relatively normal dental treatment planning. The authors present four case reports of CLL in a dental setting, as well as an update on the diagnosis, prognosis and dental treatment of patients with CLL of B-lymphocyte origin.

Fludarabine in resistant or relapsing B-cell chronic lymphocytic leukemia: the Spanish Group experience

Fludarabine produces high response rates in patients with B-cell chronic lymphocytic leukemia (CLL). Nevertheless, response to fludarabine of patients with previously treated CLL varies from 17% to 74% (0% to 38% CR). In 68 patients with heavily pretreated and advanced CLL, an overall response rate to fludarabine of 28% (4% CR) was observed. Response correlated with sensitivity of the disease to previous treatments (relapsing vs. refractory disease) (62% vs. 20%; p = 0.005) and, albeit not significantly, with the number of cycles of fludarabine (>3 vs. < or = 3) that patients could receive (36% vs. 15%; p = NS). Responding patients had a longer survival (median, not reached) than those not responding (median, 11 months) (p = 0.03). Severe toxicity was observed in some cases. It is concluded that fludarabine is a highly useful agent in CLL. However, in order to improve its effectiveness and decrease its toxicity, fludarabine should be given as soon as a lack of response to front-line therapy is observed and before the disease becomes completely resistant to therapy.

Long-term survival following cladribine (2-chlorodeoxyadenosine) therapy in previously treated patients with chronic lymphocytic leukemia

PURPOSE

To assess long-term survival following cladribine salvage treatment for previously treated patients with chronic lymphocytic leukemia.

PATIENTS AND METHODS

Fifty-two patients aged 39-84 years with previously treated CLL received cladribine 0.12 mg/kg/day in 2-hour infusions for 5 days in monthly courses. Two-thirds were refractory to previous therapy, and 8 had prior fludarabine.

RESULTS

Sixteen (31%) patients achieved complete response (CR) and 14 (27%) partial remission (PR) according to consensus criteria. Response correlated with clinical stage, number of previous treatment regimes, blood lymphocyte count, and lymphocyte halflife following the first cladribine course. Toxicity included pneumonia (n = 9), herpes zoster (n = 7), and septicemia (n = 2). Four patients in CR underwent high-dose chemotherapy with autologous blood stem cell support, and 2 remain in CR 48 and 60 months from start of cladribine, and 2 had relapse at 42 and 48 months, respectively. Median progression-free survival (Kaplan-Meier analysis) for CR patients was 23 months from start of cladribine treatment, and for PR patients 16 months. The projected overall survival was 80% at 3 years for CR patients, and the median survival 28 months for PR patients and 4 months for non-responding patients.

CONCLUSIONS

Our previous finding of durable CRs from cladribine in advanced CLL is thus confirmed in a larger patient material, and follow-up indicate that long-term survival may be achieved.