Chronic lymphocytic leukemia

High recurrence rates of squamous cell carcinoma after Mohs' surgery in patients with chronic lymphocytic leukemia

BACKGROUND

Cutaneous cancers exhibit a much higher incidence in patients with chronic lymphocytic leukemia than in nonleukemic patients. Squamous and basal cell carcinomas also exhibit greater subclinical tumor extension in patients with chronic lymphocytic leukemia.

OBJECTIVE

The purpose of this study was to estimate and compare the recurrence rates of squamous cell carcinoma after Mohs' surgery in patients with chronic lymphocytic leukemia compared with those in controls and to evaluate differences among squamous cell carcinoma size and histologic grade.

METHODS

We retrospectively assessed the clinical histories, postoperative notes, and surgical photographs of patients with chronic lymphocytic leukemia and controls matched (2:1) for age, sex, and surgical year. Both patients and controls underwent Mohs' surgery for squamous cell carcinoma of the head and neck at the Mayo Clinic between March 1988 and April 1999.

RESULTS

Twenty-eight patients who underwent Mohs' surgery for 57 squamous cell carcinomas had 7 recurrences. The cumulative incidence of recurrence on a per-tumor basis was 4.3% at 1 year, 14.8% at 3 years, and 19.0% at 5 years. Squamous cell carcinoma was seven times more likely to recur in patients with chronic lymphocytic leukemia than in controls (p = .003). The distribution of tumor histologic grade was not significantly different between patients and controls (p = .39). Maximum preoperative tumor diameters were clinically similar between patients and controls (median 15 mm vs 14 mm; p = .04).

CONCLUSION

The recurrence rates of squamous cell carcinoma were significantly higher in patients with chronic lymphocytic leukemia. Squamous cell carcinomas in patients with chronic lymphocytic leukemia did not exhibit a significant difference in histologic grade or clinical difference in preoperative tumor size. Close surveillance for squamous cell carcinoma recurrence is warranted in patients with chronic lymphocytic leukemia.

Routine analysis of IgVH mutational status in CLL patients using BIOMED-2 standardized primers and protocols

Current methods for the detection of IgVH mutational status in chronic lymphocytic leukemia (CLL), which identifies 2 subgroups of patients with significantly different outcomes, are laborious, expensive and do not lend themselves to a routine diagnostic setting. With the introduction of BIOMED-2 primers, a rapid protocol is now available. This study evaluated the protocol by examining DNA from 100 CLL patients. Conventional methods using RNA, and fluorescence in-situ hybridization (FISH) analysis for recurring chromosomal abnormalities, were carried out on 30 and 60 of these patients, respectively. There was complete concordance between the BIOMED-2 protocol and the RNA based method, both in mutational status and gene usage, whilst unmutated IgVH genes showed association with 17p13 and 11q23 deletions, and trisomy 12, associated with poor and intermediate outcomes, respectively. This study demonstrates that it is feasible to use the BIOMED-2 protocol in the diagnostic profile of CLL patients, obviating the need for inclusion of surrogate markers such as ZAP-70.

Novel molecular diagnostic and therapeutic targets in chronic lymphocytic leukaemia

B-cell lymphocytic leukaemia (B-CLL) is an indolent non-Hodgkin's lymphoma and the most frequent leukaemia. However, after many years, the incurable disease CLL has again become an exciting subject for research. Recently, both serum and molecular markers have been identified which could be used to predict the outcome of patients in early stages. With the advent of microarray analysis, novel diagnostic and therapeutic targets have been discovered. Here we describe the molecular strategies for target identification and validation. An evaluation of some established, and the most promising novel factors, with their diagnostic and prognostic applications is given. Potential therapeutic target molecules and their inhibitors are reviewed.

Quality of life of patients with chronic lymphocytic leukemia: results of a longitudinal investigation over 1 yr

OBJECTIVES

The aim of this longitudinal study was to determine the long-term quality of life (QoL) of patients with chronic lymphocytic leukemia (CLL) and to investigate the relationship between QoL and sociodemographic and clinical parameters.

METHODS

Ninety-seven patients suffering from CLL were asked to complete the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) four times over a period of 1 yr. Clinical data on disease and treatment characteristics were collected from medical records. For the purpose of comparison, EORTC QLQ-C30 scores were collected from 152 age- and gender-matched healthy controls.

RESULTS

Seventy-six patients (age: median 68 yr, range 41-89) returned one or more questionnaires and were included in the statistical analysis. Compared with healthy controls CLL patients reported a lower QoL in almost all domains. No differences regarding QoL could be observed between CLL patients who had already received chemotherapy and those who had not. Moreover, female CLL patients were found to have remarkably lower QoL scores in the areas of emotional and social functioning than male patients.

CONCLUSION

Patients suffering from CLL could have their QoL improved by more effective symptom management and psycho-oncological support. This could focus on specific symptoms such as fatigue and might have particular benefits for female patients with respect to their emotional and social well-being.

High expression of activation-induced cytidine deaminase (AID) mRNA is associated with unmutated IGVH gene status and unfavourable cytogenetic aberrations in patients with chronic lymphocytic leukaemia

Activation-induced cytidine deaminase (AID) is essential for somatic hypermutation of B-cells. We investigated the expression of AID mRNA by real-time polymerase chain reaction (PCR) in peripheral blood mononuclear cells of 80 patients with B-CLL. AID expression was detected in 45 of 80 patients (56%) at various levels, but was undetectable in 35 patients (44%). AID PCR positivity was associated with unmutated IGV(H) gene status (22 of 25 patients; P=0.002) and unfavourable cytogenetics (18 of 23 patients with deletion in 11q or loss of p53; P=0.040). Using a threshold level of 0.01-fold expression compared to Ramos control cells, even more significant associations were observed (P=0.001 for IGVH; P=0.002 for cytogenetics). A correlation was observed between individual AID levels and the percentage of V(H) homology (R=0.41; P=0.001). AID positivity predicted unmutated IGV(H) status with an odds ratio of 8.31 (P=0.003) and poor risk cytogenetics with an odds ratio of 3.46 (P=0.032). Significance was retained after adjustment for Binet or Rai stages. AID mRNA levels were stable over time. These data suggest a potential role of AID as a prognostic marker in B-CLL.

Nucleoside transporters in chronic lymphocytic leukaemia

Nucleoside derivatives have important therapeutic activity in chronic lymphocytic leukaemia (CLL). Experimental evidence indicates that in CLL cells most of these drugs induce apoptosis ex vivo, suggesting that programmed cell death is the mechanism of their therapeutic action, relying upon previous uptake and metabolic activation. Although defective apoptosis and poor metabolism often cause resistance to treatment, differential uptake and/or export of nucleosides and nucleotides may significantly modulate intracellular drug bioavailability and, consequently, responsiveness to therapy. Two gene families, SLC28 and SLC29, encode transporter proteins responsible for concentrative and equilibrative nucleoside uptake (CNT and ENT, respectively). Furthermore, selected members of the expanding ATP-binding cassette (ABC) protein family have recently been identified as putative efflux pumps for the phosphorylated forms of these nucleoside-derived drugs, ABCC11 (MRP8) being a good candidate to modulate cell sensitivity to fluoropyrimidines. Sensitivity of CLL cells to fludarabine has also been recently correlated with ENT-type transport function, suggesting that, besides the integrity of apoptotic pathways and appropriate intracellular metabolism, transport across the plasma membrane is also a relevant event during CLL treatment. As long as nucleoside transporter expression in leukaemia cells is not constitutive, the possibility of regulating nucleoside transporter function by pharmacological means may also contribute to improve therapy.

Hu1D10 induces apoptosis concurrent with activation of the AKT survival pathway in human chronic lymphocytic leukemia cells

The 1D10 antigen is the target for Hu1D10 (apolizumab), a humanized HLA-DR β-chain–specific antibody that is currently in clinical trials for hematologic malignancies. We demonstrate that Hu1D10 induces caspase-independent apoptosis following secondary cross-linking in primary chronic lymphocytic leukemia (CLL) cells. Generation of reactive oxygen species (ROS) and signal transduction, as evidenced by phosphorylation of Syk and AKT, were noted. The source of the Hu1D10-induced ROS was examined using the Raji lymphoblastic cell line with engineered defects in the mitochondrial respiratory chain. Hu1D10 treatment of clones with deficient mitochondrial respiration produced ROS suggesting a cytoplasmic source. Administration of ROS scavengers to primary CLL cells prior to Hu1D10 treatment diminished AKT activation. Treatment with Hu1D10 and the phosphatidylinositol 3-kinase inhibitor LY294002 demonstrated in vitro synergy with enhanced apoptosis. In conjunction with an ongoing clinical trial, blood samples were collected following intravenous infusion of Hu1D10 and analyzed for phosphorylation of AKT. Two of 3 patient samples showed a sustained increase in AKT phosphorylation following Hu1D10 administration. These data suggest that Hu1D10 ligation in CLL cells induces death and survival signals for which combination therapies may be designed to greatly enhance efficiency of both Hu1D10 and other class II antibodies in development.

Geldanamycin and herbimycin A induce apoptotic killing of B chronic lymphocytic leukemia cells and augment the cells' sensitivity to cytotoxic drugs

We studied the actions of geldanamycin (GA) and herbimycin A (HMA), inhibitors of the chaperone proteins Hsp90 and GRP94, on B chronic lymphocytic leukemia (CLL) cells in vitro. Both drugs induced apoptosis of the majority of CLL isolates studied. Whereas exposure to 4-hour pulses of 30 to 100 nM GA killed normal B lymphocytes and CLL cells with similar dose responses, T lymphocytes from healthy donors as well as those present in the CLL isolates were relatively resistant. GA, but not HMA, showed a modest cytoprotective effect toward CD34+ hematopoietic progenitors from normal bone marrow. The ability of bone marrow progenitors to form hematopoietic colonies was unaffected by pulse exposures to GA. Both GA and HMA synergized with chlorambucil and fludarabine in killing a subset of CLL isolates. GA- and HMA-induced apoptosis was preceded by the up-regulation of the stress-responsive chaperones Hsp70 and BiP. Both ansamycins also resulted in down-regulation of Akt protein kinase, a modulator of cell survival. The relative resistance of T lymphocytes and of CD34+ bone marrow progenitors to GA coupled with its ability to induce apoptosis following brief exposures and to synergize with cytotoxic drugs warrant further investigation of ansamycins as potential therapeutic agents in CLL.

Oral fludarabine has significant activity in patients with previously untreated chronic lymphocytic leukemia, and leads to increased STAT1 levels in vivo

Fifteen patients with previously untreated chronic lymphocytic leukemia (CLL) were treated with oral fludarabine. Toxicities were mainly hematologic, and the response rate was 80%. To assess the effect of fludarabine on the transcription factor STAT1, blood samples obtained on study entry were treated in vitro with fludarabine for 24 h, and the majority of samples displayed an expected decrease in STAT1. To determine whether similar changes occurred in vivo, we developed a flow cytometric assay to quantitate STAT1 levels. On completion of fludarabine cycle 1, CLL cells showed increased STAT1 in the majority of patients, in contrast to the in vitro findings. This may reflect a survival advantage for cells that express high levels of STAT1. In conclusion, oral fludarabine is highly active and merits further investigation in previously untreated patients with CLL. Larger studies are indicated to determine optimal timing of STAT1 assessment, and if changes in STAT1 represent an in vivo indicator of response to purine analog therapy.

Activation of the Wnt signaling pathway in chronic lymphocytic leukemia

B cell chronic lymphocytic leukemia (CLL) is characterized by an accumulation of mature, functionally incompetent B cells. Wnts are a large family of secreted glycoproteins involved in cell proliferation, differentiation, and oncogenesis. The classical Wnt signaling cascade inhibits the activity of the enzyme glycogen synthase kinase-3beta, augmenting beta-catenin translocation to the nucleus, and the transcription of target genes. Little is known about the potential roles of Wnt signaling in CLL. In this study, we quantified the gene expression profiles of the Wnt family, and their cognate frizzled (Fzd) receptors in primary CLL cells, and determined the role of Wnt signaling in promoting CLL cell survival. Wnt3, Wnt5b, Wnt6, Wnt10a, Wnt14, and Wnt16, as well as the Wnt receptor Fzd3, were highly expressed in CLL, compared with normal B cells. Three lines of evidence suggested that the Wnt signaling pathway was active in CLL. First, the Wnt/beta-catenin-regulated transcription factor lymphoid-enhancing factor-1, and its downstream target cyclin D1, were overexpressed in CLL. Second, a pharmacological inhibitor of glycogen synthase kinase-3 beta, SB-216763, activated beta-catenin-mediated transcription, and enhanced the survival of CLL lymphocytes. Third, Wnt/beta-catenin signaling was diminished by an analog of a nonsteroidal antiinflammatory drug (R-etodolac), at concentrations that increased apoptosis of CLL cells. Taken together, these results indicate that Wnt signaling genes are overexpressed and are active in CLL. Uncontrolled Wnt signaling may contribute to the defect in apoptosis that characterizes this malignancy.

B cell chronic lymphocytic leukaemia cells have reduced capacity to upregulate expression of MHC class I in response to interferon-γ

AIMS

An important consideration in the design of a tumour vaccine is the ability of tumour-specific cytotoxic T lymphocytes (CTL) to recognise unmanipulated tumour cells in vivo. To determine whether B-CLL might use an escape strategy, the current studies compared B-CLL and normal B cell MHC class I expression.

METHODS

Flow cytometry, TAP allele PCR and MHC class I PCR were used.

RESULTS

While baseline expression of MHC class I did not differ, upregulation of MHC class I expression by B-CLL cells in response to IFN-gamma was reduced. No deletions or mutations of TAP 1 or 2 genes were detected. B-CLL cells upregulated TAP protein expression in response to IFN-gamma. Responsiveness of B-CLL MHC class I mRNA to IFN-gamma was not impaired.

CONCLUSIONS

The data suggest that MHC class I molecules might be less stable at the cell surface in B-CLL than normal B cells, as a result of the described release of beta(2)m and beta(2)m-free class I heavy chains from the membrane. This relative MHC class I expression defect of B-CLL cells may reduce their susceptibility to CTL lysis in response to immunotherapeutic approaches.

The antiapoptotic effects of blood constituents in patients with chronic lymphocytic leukemia

OBJECTIVE

Clonal B-lymphocytes of chronic lymphocytic leukemia (B-CLL) are characterized by decreased sensitivity to programmed cell death and, therefore, they accumulate in vivo. However, these malignant cells die rapidly in vitro. In the current study we concentrated on the contribution of autologous serum (AS) and lymphocyte subsets to the survival of the malignant cells in vitro.

METHODS

Mononuclear cells from the peripheral blood of 26 CLL patients and 24 controls were incubated overnight in the presence or absence of AS and heat-inactivated AS (HI-AS) or fetal calf serum (FCS). Also, isolated B cells were incubated at different concentrations in the presence of AS and/or isolated T cells. The level of apoptosis of CD19+ cells was measured by flow cytometry.

RESULTS

Spontaneous apoptosis of unfractionated B-CLL cells incubated with AS, FCS or without serum was significantly lower than the rate of B-cell death in the control group, in similar culture conditions. AS had an antiapoptotic effect on unfractionated B-CLL cells when compared with FCS. The rate of apoptosis of B-CLL cells was directly associated with stage. HI of AS had a variable effect, which was related to the stage of the disease. High concentrations of B cells and the addition of autologous T cells reduced the rate of apoptosis when incubated without serum. The antiapoptotic effect of T cells was most prominent in progressive stages.

CONCLUSIONS

B-CLL cells exhibit decreased spontaneous apoptosis, which is partially prevented by humoral (AS) and cellular (T cells and B-CLL cells) factors. The equilibrium between apoptotic and antiapoptotic factors changes with disease progression.

Albumin activates the AKT signaling pathway and protects B-chronic lymphocytic leukemia cells from chlorambucil- and radiation-induced apoptosis

Activation of the phosphatidylinositol 3- kinase/AKT pathway antagonizes apoptosis in diverse cellular systems. We previously showed that human plasma activated AKT and potently blocked the ability of chlorambucil or gamma radiation to induce apoptosis of B-chronic lymphocytic leukemia (CLL) cells. Here we report experiments that identify albumin as the major component of plasma that blocks CLL cell killing by chlorambucil or radiation. Intact plasma depleted of albumin by chromatography on Cibacron blue-Sepharose or plasma from a subject with analbuminemia failed either to activate AKT or to protect CLL cells from chlorambucil-induced apoptosis. Both functions were restored by re-addition of albumin. The protective action of albumin as well as AKT activation was compromised by the binding of lipids. Fluorescence-activated cell sorter (FACScan) analysis demonstrated the uptake of fluoresceinated albumin by CLL cells. Accumulation of albumin in intracellular vesicles was also shown by confocal microscopy. Indirect inhibition of AKT activation by the phosphatidylinositol 3-kinase inhibitor LY294002 reversed the blockade of chlorambucil-induced killing by plasma albumin. The data suggest that activation of AKT consequent to binding of albumin by CLL cells blocks chlorambucil- and radiation-induced apoptosis. Strategies designed to block albumin-induced antiapoptotic signaling may, therefore, be of value in enhancing cytotoxic drug action on CLL cells.

Lymphocytic infiltrates and subclinical epithelial tumor extension in patients with chronic leukemia and solid-organ transplantation

BACKGROUND

Dense infiltrates in association with squamous cell carcinoma (SCC) or basal cell carcinoma (BCC) in patients with underlying chronic lymphocytic leukemia (CLL) may complicate pathologic interpretation of histologic margins.

OBJECTIVE

The study was conducted to determine the frequency of identifying dense inflammatory infiltrates in frozen histologic sections during Mohs operation for BCC or SCC in patients with CLL and organ-transplant recipients, to characterize the infiltrate (reactive versus leukemic) in CLL, and to estimate the subclinical tumor extension in patients with CLL, transplant recipients, and control subjects undergoing Mohs procedure.

METHODS

Frozen sections of head and neck BCC and SCC obtained during Mohs procedures in patients with CLL, organ transplant recipients, and a control group were reviewed retrospectively. Biopsy specimens of CLL with dense infiltrates were assessed with immunohistochemical stains. Subclinical tumor extension (postoperative defect size minus preoperative tumor size) was evaluated in each group.

RESULTS

Dense infiltrates were found in tumors of 20 of 55 patients with CLL (36%), 1 of 8 transplant recipients (13%), and 1 of 105 controls (1%). In patients with CLL, 75% of the dense infiltrates were B-cell leukemic. Compared with controls, the mean subclinical tumor extension was larger in patients with CLL (P=0.029) and in transplant recipients (P=0.55).

CONCLUSION

Dense leukemic infiltrates associated with BCC or SCC in CLL may complicate pathologic interpretation of Mohs surgical histologic margins and may be associated with larger postoperative defects relative to preoperative clinical tumor appearance. In patients with CLL, as in transplant recipients, SCC seems more likely to develop than BCC.

Aberrant expression of B-lymphocyte stimulator by B chronic lymphocytic leukemia cells: a mechanism for survival

B-cell chronic lymphocytic leukemia (B-CLL) is defined by the accumulation of CD5(+) B cells in the periphery and bone marrow. This disease is not characterized by highly proliferative cells but rather by the presence of leukemic cells with significant resistance to apoptosis and, therefore, prolonged survival. B-lymphocyte stimulator (BLyS) is a newly identified tumor necrosis factor (TNF) family member shown to be critical for maintenance of normal B-cell development and homeostasis and it shares significant homology with another TNF superfamily member, APRIL. The striking effects of BLyS on normal B-cell maintenance and survival raises the possibility that it may be involved in pathogenesis and maintenance of hematologic malignancies, including B-CLL. In this study, we investigated the status of APRIL and BLyS expression, as well as their receptors, in this disease. All B-CLL patient cells studied expressed one or more of 3 known receptors for BLyS; however, the pattern of expression was variable. In addition, we demonstrate for the first time that B-CLL cells from a subset of patients aberrantly express BLyS and APRIL mRNA, whereas these molecules were not detectable in normal B cells. Furthermore, we provide in vitro evidence that BLyS protects B-CLL cells from apoptosis and enhances cell survival. Because these molecules are key regulators of B-cell homeostasis and tumor progression, leukemic cell autocrine expression of BLyS and APRIL may be playing an important role in the pathogenesis of this disease.

Role of caspases and apoptosis-inducing factor (AIF) in cladribine-induced apoptosis of B cell chronic lymphocytic leukemia

We have evaluated the role of caspases and the mitochondrial apoptosis inducing-factor (AIF) in apoptosis induced by cladribine (2CdA), in vitro, in cells from patients of B-CLL and in peripheral blood lymphocytes from normal donors. In sensitive B-CLL cells, apoptosis was characterized by cell shrinking, loss of mitochondrial membrane potential (DeltaPsi(m)), phosphatidylserine exposure, activation of caspases 3, 7, 8 and 9, reduction of Mcl-1 levels, translocation of AIF from mitochondria to nucleus and chromatin condensation. No significant variations in the levels of Bcl-2, Bax and Bak proteins were noticed upon treatment with 2CdA. Co-treatment of cells with the pan-caspase inhibitor Z-VAD-fmk attenuated some morphological and biochemical characteristics of apoptosis and delayed 2CdA-induced DeltaPsi(m) loss, but did not prevent cell death. Z-VAD-fmk did not prevent 2CdA-induced AIF translocation but in this case apoptotic cells displayed only peripheral chromatin condensation, characteristic of AIF action. Reduced or negligible caspase 3 expression did not prevent 2CdA toxicity in cells from four patients. Cells from three patients that responded poorly to 2CdA lacked expression of caspases 9 or 3. Cells from another patient resistant to 2CdA expressed caspases 3, 7, 8 and 9 but they were not activated by treatment. These results indicate that execution of apoptosis is carried out independently by AIF and caspases, which are responsible for the development of apoptotic phenotype in response to 2CdA. Although caspases can also collaborate in DeltaPsi(m) loss, proapoptotic proteins from the Bcl-2 superfamily may be the key inducers of DeltaPsi(m) loss and apoptosis in B-CLL cells sensitive to 2CdA.

Chronic lymphocytic leukaemia: a model for investigating potential new targets for the therapy of indolent lymphomas

We address two key issues whose investigation may help to define new prognostic parameters and new potential targets for therapeutic intervention. First, which are the conceptual implications of the cellular origin of indolent lymphomas? Second, how may deciphering the biology of chronic lymphocytic leukaemia (CLL) lead to the development of new modalities of treatment? The latter issue is articulated in the following three key questions. (1) Which are the molecular pathways through which the microenvironment exerts its influence on the malignant clone? (2) What are the relationships between proliferation and defective apoptosis? (3)Is there any evidence of a role for antigenic stimulation?

Surface membrane antigen expression changes induced in vitro by exogenous growth factors in chronic lymphocytic leukemia cells

The factors determining the growth and survival of cells in B chronic lymphocytic leukemia (CLL) have remained poorly understood. We investigated the effects of optimal mitogen combinations (OMCs) on the expression of 26 surface membrane antigens among 33 CLL patients. The seven OMCs used were selected after pre-testing 14 combinations of (1) S. aureus Cowan I (SAC), (2) interleukin-2 (IL-2), (3) tumor necrosis factor alpha (TNF-alpha) and (4) 12-O-tetradecanoylphorbol 13-acetate (TPA; also known as phorbol 12-myristate 13-acetate or PMA). In flow cytometry we revealed that OMCs induced statistically highly significant upregulation of the expression of CD5, CD11c, CD19, CD22, CD23, CD25, CD38, CD40, CD45, CD45RO, CD95, CD126, CD130 and FMC7, and downregulation of CD20 and CD124 expression. Interestingly, the expression of CD27, CD45RA, CD79b, CD80, CD122 and that of the immunoglobulin gene superfamily members CD21, Ig-kappa, Ig-lambda, Ig-delta and Ig-micro were not significantly affected under similar conditions. The expression of several antigens was co-regulated, suggesting common regulatory pathways. These antigens include CD11c/CD5, CD11c/CD22, CD11c/CD126, CD11c/FMC7 as well as CD27/CD45, CD27/CD45RA and CD27/CD79b. Upregulation of surface antigen expression, induced by OMCs, should be applicable in antibody therapy in vitro and in vivo, and in negative stem cell selection for autotransplantation. Furthermore, the current strategy to enhance cell surface antigen expression may be a versatile tool to raise humoral and cell-mediated host defense against CLL cells. Upregulation of proteins mediating positive growth signals (eg CD25, CD40) and negative signals or apoptosis (eg CD95) may be used to sensitize cells to chemotherapy and programmed cell death.

Impact of cardiac surgery using cardiopulmonary bypass on course of chronic lymphatic leukemia: a case-control study

BACKGROUND

Chronic lymphatic leukemia (CLL) is a common disease among elderly individuals. The number of older patients undergoing operations with cardiopulmonary bypass (CPB) is increasing. The aim of the present study was to evaluate the impact of cardiac surgery using CPB on the long-term course of CLL.

METHODS

From 1992 to 2000, a total of 28 patients with CLL underwent heart surgery using CPB at our institution (group I). These patients were compared with 25 patients from the CLL register who were retrospectively matched with regard to preoperative administration of chemotherapy, Binet classification, age, and sex (group II). A time-point was selected for each patient in group II so that the variables for the two groups corresponded in relation to the time of operation of the patients in group I. Midterm follow-up data in both groups were analyzed.

RESULTS

There were no differences between groups regarding matched variables. The mean follow-up time was similar in both groups (2.6 +/- 2.2 vs 2.3 +/- 1.3 years, p > 0.5). The 30-day mortality in group I was 14.3%. The mean stay in the intensive care unit was 4.2 +/- 7.5 days; the median number of units of packed red blood cells transfused was three (range 0 to 17). Compared with group II, in group I significantly fewer patients (11 vs 17, p = 0.049) required chemotherapy significantly later (1.98 +/- 2.06 vs 0.84 +/- 1.18 years, p = 0.018). During follow-up, no difference was found between groups regarding severe infections (10 vs 14, p = 0.14). Despite postoperative mortality in group I, the long-term mortality was similar in both groups (p = 0.3).

CONCLUSIONS

Cardiac surgery using CPB did not have a negative impact on the natural course of CLL. Moreover, this procedure seems to be associated with a decrease in the number of postoperative chemotherapy administrations and with an increase of chemotherapy-free survival time. Although CLL may be a risk factor in the early postoperative period, it is not a contraindication for cardiac surgery using CPB.

CD80 antigen expression as a predictor of ex vivo chemosensitivity in chronic lymphocytic leukemia

We investigated the correlation between expression of 31 surface membrane antigens and chemosensitivity of peripheral blood mononuclear cells from 36 patients with CLL. The sensitivity of CLL cells to nine drugs (2'-chlorodeoxyadenosine, cisplatin, chlorambucil, cyclosporin A, doxorubicin, fludarabine, prednisolone, verapamil and vincristine) and two types of irradiation (gamma and UV-irradiation) was determined from dose-response curves of 4-day cultures ex vivo. The results indicated that the CLL cases responding to purine analogs (2'-chlorodeoxyadenosine and fludarabine) can be identified according to CD80 expression: all resistant cases had low or negative CD80 expression. No other correlations were revealed. CD80 may be a surrogate chemosensitivity marker for purine analogs.

Surface antigen expression in chronic lymphocytic leukemia: clustering analysis, interrelationships and effects of chromosomal abnormalities

Chronic lymphocytic leukemia (CLL) is a phenotypically distinguishable form of B-lymphoid leukemias. The regularity of surface membrane antigen expression patterns, their interrelationships as well as the effects of the three frequent chromosomal aberrations, ie 11q deletion, 13q deletion and trisomy 12, were investigated in 35 classic CLL cases by flow cytometry. The two-way cluster analysis of 31 individual antigens revealed three expression patterns: (1) most cells in most cases positive (CD5, CD19, CD20, CD23, CD27, CD40, CD45, CD45RA); (2) most cells in most cases negative (CD10, CD14, CD34, CD122, CD154, mIgG); and (3) a mixed pattern with a variable number of positive cases and a variable percentage of positive cells in individual cases (CD11c, CD21, CD22, CD25, CD38, CD45RO, CD79b, CD80, CD95, CD124, CD126, CD130, FMC7, mIgD, mIgkappa, mIglambda, mIgM). The expressions of several antigens were strongly interdependent, even when antigens belonged to entirely different gene families. Such antigen pairs were: CD11c/CD21; CD19/CD45; CD19/CD79b; CD22/CD45RA; CD23/Igkappa; CD25/mIgM; CD27/CD45; CD45/CD79b; CD45RA/Igkappa. In contrast, the expression of some antigens was mutually exclusive, the best examples being CD45RA/CD45RO, CD38/CD80 and CD45RA/CD80. Deletion of chromosome arm 11q attenuated expression of splicing variant CD45RA, but enhanced CD45RO expression. In contrast, cases of trisomy 12 were associated with enhanced CD45RA and attenuated CD45RO expression. Similarly, trisomy 12 was associated with enhanced CD27 and mIgkappa expression. The variable levels of signaling surface membrane antigens, their interactions and interference by genetic aberrations are likely to affect the clinical progression and drug response of CLL.

CD5-induced apoptosis of B cells in some patients with chronic lymphocytic leukemia

Although B chronic lymphocytic leukemia (B-CLL) is characterized by prolonged survival of CD5(+) B cells in vivo, these cells apoptose spontaneously in vitro. The effect of CD5 ligation on apoptosis was studied in 27 newly diagnosed patients with B-CLL, in relation to the expression of surface IgM (sIgM), CD79b, CD38, CD72 and CD19. B cells from 15 patients (group I) were resistant to anti-CD5-induced apoptosis, whereas apoptosis above spontaneous levels was seen in the remaining 12 studied (group II). Group II was then subdivided on the basis of differences in the time required to reach maximum apoptosis: whilst B cells from seven patients underwent apoptosis by 18 h, those from the remaining five needed 36 h to apoptose. The expression of sIgM, CD5, CD79b and CD38 was higher in group II than group I, suggesting that signaling for apoptosis might operate via CD79, and that CD38 expression was required. As shown by flow cytometry and confirmed by Western blotting, apoptosis was associated with a decrease in the ratios of Bcl-2/Bax and Bcl(XL)/Bax, due to an increase in the level of Bax, but no change in that of Bcl-2. This heterogeneous apoptotic response to CD5 ligation offers an explanation for the incomplete success of anti-CD5 monoclonal therapy, and might help identify patients who would respond to such treatment.

The class II tumor-suppressor gene RARRES3 is expressed in B cell lymphocytic leukemias and down-regulated with disease progression

The molecular pathogenesis of B cell chronic lymphocytic leukemia (B-CLL), the most common form of leukemia, remains unknown. We have used the mRNA differential display technique to analyze genes that may be involved in the development/progression of B-CLL. We have identified the tumor suppressor retinoic acid receptor responder 3 (RARRES3) as a B-CLL-related gene. RARRES3 maps to chromosome band 11q23, a region frequently deleted in lymphoproliferative disorders. To assess the potential involvement of RARRES3 in leukemogenesis, we examined 24 cases of B-CLL, 10 of acute lymphocytic leukemia (ALL) and five related cell lines by RT-PCR and sequence analyses. We report a correlation between RARRES3 down-regulation and B-CLL progression. We also found decreased RARRES3 gene levels in ALL cases and in the five cell lines studied. We did not find mutations in any of the leukemia samples assayed, including those with 11q23 deletion. These results indicate that RARRES3 may play a role in B-CLL progression.