Functional and clinical relevance of CD44 variant isoform expression on B-cell chronic lymphocytic leukemia cells

BACKGROUND AND OBJECTIVE: Recent studies have shown that expression of adhesion molecules of the Ig superfamily, of integrins and of selectins allows definition of high vs low risk B-cell chronic lymphocytic leukemia (B-CLL). The proteoglycan CD44 is an adhesion molecule that may be expressed as a standard form of 85-95 KD or as several variant isoforms. The presence of certain CD44 variant (v) isoforms on neoplastic cells indicates poor prognosis in epithelial and lymphoid malignancies, as it is associated with tumor progression and metastasis. DESIGN AND METHODS: The expression of CD44 v3, 4, 5, 6, 7, 9 and 10 was analyzed in cells from 85 B-CLL patients. Indirect immunofluorescence and flow cytometry were used to identify CD44v. Functional studies were performed by analysis of adhesion to hyaluronate (HA), one CD44 ligand, and HA-induced Ca2+ influx. A variety of statistical methods were used to define phenotypic and functional differences between the various clones, to calculate survival curves, and for multivariate analyses. RESULTS: In 17/85 B-CLL (20%), one or more CD44v were detectable by indirect immunofluorescence, whereas in 68/85 cases (80%) this technique yielded negative results. However, moAb "mixes" against CD44v and patching of surface molecules on B-CLL cells have shown that all B-CLL clones express CD44v. This has been confirmed by Western blot in a number of cases. Thus, two groups of patients whose cells bear CD44v at high or low density, are distinguished. Functions of the two clonotypes were investigated, namely their adhesion to a CD44 ligand and hyaluronate (HA), and effect on HA-induced Ca2+ influx. Cells expressing high density CD44v adhere to HA-coated substrates more efficiently than cells with low density CD44v. In all clones, HA-signaling via CD44 yields Ca2+ influx. This indicates that CD44 mediates activatory signals following interaction with the ligand. INTERPRETATION AND CONCLUSIONS: The clinical relevance of these findings has been ascertained. The 17/85 cases whose cells bore high density CD44v had significantly worse prognostic features than those of patients with low density CD44v, namely more advanced disease stage, LDT < 12 months and therapy requirement. Moreover, the median survival in the former group of patients was < 5 years as opposed to > 12 years in the latter. Therefore, analysis of CD44v expression provides indications of biological and clinical relevance also in low grade lymphoproliferative disorders.     

Myelomonocytic antigens in B-cell chronic lymphocytic leukemia

The clinical significance of myelomonocytic (MyMo) antigens in B-cell chronic lymphocytic leukemia (B-CLL) is unclear. We have analyzed the expression of MyMo antigens (CD13, CD14 (LeuM3, My4, Mo2), CD15, CD11b, CD11c, CD33 and CD68) on B-lymphocytes (CD19+) in 105 B-CLL patients and in 35 controls. A double direct staining technique and flow cytometric analysis was performed. The expression of MyMo antigens on the control group did not exceed 4% B-lymphocytes. A MyMo antigen was considered as positive when present in > or = 10% of B-lymphocytes. Among the B-CLL patients, 28 (26.7%) were positive for CD11c, 21 (20.0%) for CD11b, nine (8.6%) for CD15, five (4.8%) for CD13, two (1.9%) for Mo2, and one (1.0%) for My4. No patient was positive for LeuM3, CD33 or CD68. CD11c was more frequently expressed in patients with a short lymphocyte doubling time (< 12 months) (P = 0.05) and CD11b in the group with a higher number of lymphoid areas involved (P = 0.02). No correlation was found between lymphoid morphology and MyMo antigen expression. Fourteen of the 80 patients at risk subsequently progressed to a more advanced stage. Multivariate analysis identified hemoglobin (P = 0.004) and CD11b positivity (P = 0.009) as independent variables for disease progression. Fifteen patients died during evolution. Seven out of the 21 CD11b positive patients and eight of the 84 CD11b negative patients died (LR: P = 0.02, BG: P = 0.05). In the multivariate analysis, only CD11b positivity (> or = 10%) added prognostic value to clinical stages.     

Twenty years of research on B-cell chronic lymphocytic leukemia

The typical MRI features of the most common pancreatic diseases, such as pancreatitis and adenocarcinoma of the pancreas, have been established. However, even in these common pancreatic disorders, MRI correlation with the underlying pathology is limited for clinical reasons. We emphasize MR-pathological correlation of inflammatory and neoplastic pancreatic changes, including pancreatitis, adenocarcinoma, acinar cell carcinoma, rare cystic and solid pancreatic neoplasms, and islet cell tumors. By highlighting the correlation of key pathological features with MR findings, a better understanding of the MR appearance of pancreatic pathology can be provided. In addition, MRI may prove a powerful tool in detection and characterization of pancreatic tumors.     

The cellular biology of B-cell chronic lymphocytic leukemia

In conclusion, B-CLL cells through their immunophenotype have the functional potential required to interact with cells in what has been called the immunological synapse, i.e. the cognate interactions between T-cells, antigen-presenting cells and B-cells during immunopoiesis. The data reviewed herein provides substantial evidence to suggest that B-CLL cells in fact can interact, not only with T-cells but also with endothelial cells and stromal cells in the bone marrow. These interactions, in particular signaling through CD40, contribute to extended survival and proliferation of B-CLL cells and, thereby, the risk of complete malignant transformation of the clone. Therefore, this review would suggest that the answers to how B-CLL is initiated may be found in molecules responsible for the normal regulation of immunopoiesis. Transformation to malignancy, by contrast, is likely to be caused by loss of control over the G1 restriction in the cell cycle in B-CLL cells.     

Deficiency of the ATM protein expression defines an aggressive subgroup of B-cell chronic lymphocytic leukemia

The gene mutated in ataxia telangiectasia, ATM, on human chromosome 11q22-q23 is implicated in cell cycle control and DNA repair. Ataxia telangiectasia patients as well as ATM-deficient mice are immune deficient and develop lymphoproliferative disease. Abnormalities in 11q22.3-q23.1 have also been described in B-cell chronic lymphocytic leukemia (B-CLL). We analyzed B-CLL samples for loss of heterozygosity (LOH) using microsatellite markers located at the ATM (D11S2179), mixed-lineage leukemia (MLL; D11S1356), and BCL1 (D11S987) loci, all of which are located around 11q23. Five (14%) of 36 informative cases showed LOH at the ATM gene, and two of these five cases had LOH at the MLL gene. No LOH was detected at the BCL1 locus, and none of the cases showed LOH at the MLL gene without LOH at the ATM gene. Four of these five cases with LOH at the ATM gene were studied for ATM protein expression by Western blot analysis. All four cases lacked ATM protein. An additional 111 cases of B-CLL were studied for expression of ATM protein by Western blot analysis and RIA. Thirty-eight (34%) of these cases showed ATM levels <50% of that seen in normal lymphoid cells. No morphological or immunophenotypic difference was observed between ATM-deficient B-CLL cases and cases with normal ATM expression. However, patients with ATM deficiency had significantly shorter survival times (35.66 versus 97.3 months; P = 0.003) and more aggressive disease, suggesting that ATM is involved in the leukemogenesis of B-CLL. These data also suggest that the ATM gene may play a role in the reported 11q23 abnormality in B-CLL, which also characterizes an aggressive disease.     

In vitro modulation of bcl-2 protein expression, drug-induced apoptosis and cytotoxicity by interleukin-10 in chronic lymphocytic leukemia

Interleukin-10 failed to modify either the percentage of bcl-2+ cells or the number of bcl-2 molecules, or to reduce 2-chlorodeoxyadenosine- and fludarabine-induced apoptosis. The cytokine at 0.1 ng/mL induced an increase of cell survival both in the absence or in the presence of 2-chlorodeoxyadenosine, while no difference was appreciated with fludarabine.     

Aspirin and salicylate induce apoptosis and activation of caspases in B-cell chronic lymphocytic leukemia cells

We analyzed the effect of aspirin, salicylate, and other nonsteroidal antiinflammatory drugs (NSAIDs) on the viability of B-chronic lymphocytic leukemia (B-CLL) cells. Aspirin induced a decrease in cell viability in a dose- and time-dependent manner. The mean IC50 for cells from 5 patients was 5.9 +/- 1.13 mmol/L (range, 4.4 to 7.3 mmol/L). In some cases, 2.5 mmol/L aspirin produced an important cytotoxic effect after 4 days of incubation. No effect was observed with other NSAIDs, at concentrations that inhibit cyclooxygenase, such as ketorolac (10 micromol/mL), NS-398 (100 micromol/mL), or indomethacin (20 micromol/mL), thus suggesting the involvement of cyclooxygenase-independent mechanisms in aspirin-induced cytotoxicity. Salicylate also produced dose-dependent cytotoxic effects on B-CLL cells and the mean IC50 for cells from 5 patients was 6.96 +/- 1.13 mmol/L (range, 5 to 7.8 mmol/L). Both aspirin and salicylate induced DNA fragmentation and the proteolytic cleavage of poly(ADP(adenosine 5'-diphosphate)-ribose) polymerase (PARP), demonstrating that both compounds induce apoptosis of B-CLL cells. Finally, inhibition of caspases by Z-VAD.fmk blocked proteolytic cleavage of PARP, DNA fragmentation, and cytotoxicity induced by aspirin. Mononuclear cells from normal donors showed a lower sensitivity than cells from B-CLL patients to aspirin as determined by analysis of cell viability. B and T lymphocytes from normal donors and T lymphocytes from CLL patients are more resistant to aspirin-induced apoptosis, as determined by analysis of phosphatidylserine exposure. These results indicate that aspirin and salicylate induce apoptosis of B-CLL cells by activation of caspases and that this activation involves cyclooxygenase-independent mechanisms.     

Syndecan-1 expression on malignant cells from the blood and marrow of patients with plasma cell proliferative disorders and B-cell chronic lymphocytic leukemia

Syndecan-1 is a low-affinity receptor for basic fibroblast growth factor (bFGF). In this study, we used flow cytometry to examine expression of syndecan-1 on monoclonal cells from the blood (n = 37) and marrow (n = 81) of patients with plasma cell (PC) proliferative disorders (PCPD) and blood cells from patients (n = 39) with B cell chronic lymphocytic leukemia (B-CLL). The marrow CD38+CD45- and CD38+CD45+ PC were syndecan-1 positive in all patients with PCPD and there was no difference between patients with monoclonal gammopathy of undetermined significance (MGUS) vs multiple myeloma or cases with vs without bone lesions. In 38% of cases, syndecan-1 expression on the PC was heterogeneous with > or =25% of PC syndecan-1 negative. We found similar syndecan-1 expression on blood and marrow PC in the 36 cases with paired samples. CLL cells were syndecan-1 negative in 97% (38/39) of the cases. Syndecan-1 is a useful marker to detect malignant plasma cells in the blood or marrow; however, it is not helpful in distinguishing MGUS from active myeloma. In addition, syndecan-1 is present on the less mature (CD45+) PC, and there is heterogeneity of expression within and between patients. The relevance of the bFGF bound to myeloma cells via syndecan-1 remains to be elucidated.     

p53 expression in B-cell chronic lymphocytic leukemia: a marker of disease progression and poor prognosis

We have analyzed by immunocytochemistry (ICC) the frequency of p53 protein expression in 181 cases of B-cell chronic lymphocytic leukemia (CLL) followed at a single institution to assess the relationship between p53 and the clinical and morphological features of the disease, as well as the possible involvement of this protein in the pathogenesis of the more aggressive forms of CLL. The overall frequency of p53 protein positivity in CLL was 15% (27 of 181 cases). There were no significant differences in age, sex, absolute lymphocyte count, or lymphocyte doubling time between p53-positive and -negative patients. By contrast, p53-positive patients had a significantly higher percentage of prolymphocytes (P = .002) and a significantly lower percentage of residual CD3-positive T lymphocytes (P = .0001). No correlation was found between the percentage of p53-positive cells and the percentage of cells in cycle assessed by the monoclonal antibody Ki-67. When the percentage of p53 positivity was correlated with the clinical stage of the disease, the proportion of p53-positive cases increased significantly from Binet's stage A (8 of 108; 7.4%), to stage B (12 of 49; 24.4%) and C (7 of 24; 29.2%) (P = .002). p53 positivity correlated also with the phase of the disease, showing a low expression at diagnosis (8 of 112; 7.1%) and a significantly higher expression in patients studied during the course of the disease (7 of 35; 20%) and, to a further extent, with disease progression (12 of 34; 35.3%) (P = .0001). The association of p53 protein expression with mutations in the gene was confirmed by direct sequence of the entire cDNA in 15 of the 17 ICC positive cases tested (88%). A significantly shorter treatment-free interval from diagnosis (P = .003) and a poorer response to therapy (P = .007) was observed in p53-positive compared with p53-negative patients. Overall survival from the time of diagnosis, as well as from the time of p53 protein analysis, was significantly shorter in patients with p53 protein expression (P = .03 and .0001, respectively). Moreover, in multivariate analysis, p53 expression and stage C were independently associated with a short survival. The results of this study indicate that in CLL the expression of the p53 protein, analyzed by a simple and reliable immunocytochemical method, is strongly associated with p53 gene mutations, a morphological variant (CLL with >10% prolymphocytes), advanced clinical stage, progressive disease, poor response to therapy, and short survival.     

Simultaneous occurrence of B-cell chronic lymphocytic leukemia and chronic myeloid leukemia with further evolution to lymphoid blast crisis

The coexistence of chronic myeloid leukemia (CML) and B-cell chronic lymphocytic leukemia (CLL) in the same patient is rare. A 71-year-old woman developed a B-lineage lymphoid blast crisis at 18 months after diagnosis of Ph-positive CML. At this time, a lymphoid cell population with morphologic and immunophenotypic features of CLL was demonstrated. The retrospective review of the tests performed at diagnosis and thereafter disclosed the presence of lymphoid nodules in the initial bone marrow biopsy in the absence of lymphocytosis. Subsequently, there was an appearance of moderate lymphocytosis in the following months. Therefore, diagnosis of CML and coexistent CLL was established. Although a transient remission of blast crisis was achieved, blast cells reappeared two months later and the patient died shortly afterwards. Molecular studies of the immunoglobulin heavy chain gene (IH) rearrangement pattern point to the origin of the diseases in two different cell clones. In addition, previously published cases of simultaneous CLL and CML are reviewed.     

High incidence of relapse after autologous stem-cell transplantation for B-cell chronic lymphocytic leukemia or small lymphocytic lymphoma

BACKGROUND: High-dose therapy followed by autologous stem-cell transplantation (autoSCT) induces complete remissions in the majority of patients with advanced B-cell chronic lymphocytic leukemia or small lymphocytic lymphoma (B-CLL). However, the long-term utility of this therapy for B-CLL is unknown. PATIENTS AND METHODS: Sixteen previously treated patients with B-CLL were transplanted using autologous blood (n = 13) or bone marrow (n = 3). The median age of the patients was 49 f1p4s (range 44-60 years), and the median number of prior chemotherapy regimens was two. Patients were eligible for transplantation if they had chemosensitive disease and no morphologic evidence of malignant cells in the graft. Preparative regimens included cyclophosphamide and total-body-irradiation, with or without cytarabine, or BEAC. RESULTS: All patients engrafted and achieved a complete remission posttransplant. Ten patients were alive at a median of 41 months (range 22-125 months), and five were disease-free. Eight patients have relapsed and six have died (three from progressive malignancy). The projected three-year overall survival, failure-free survival and relapse rates were 68%, 37%, and 56%, respectively. CONCLUSIONS: AutoSCT for advanced B-CLL is associated with a high relapse rate. Whether this therapy can prolong life or produce cures is uncertain.     

5''-nucleotidase activity in lymphocytes from patients affected by B-cell chronic lymphocytic leukemia

Port site metastasis often occurs after laparoscopic colorectal resection of Dukes B and Dukes C tumors. To evaluate the feasible indication for laparoscopic surgery for the cure of colorectal cancer, we performed a clinicopathologic study with special reference to tumor size. A total of 233 patients who underwent curative resection of colorectal cancer at our department during 15 years were examined. There were 59 Dukes A tumors, and their mean size was 2.86 cm. Tumors < 2 cm, compared with tumors > 2 cm, were characterized by grossly superficial type (68% vs. 9%, p < 0.01), negative serosal invasion (95% vs. 24%, p < 0.01), and absence of lymph node metastasis (91% vs. 60%, p < 0.01). Among tumors < 3 cm, node-negative cases were distinguished by location in the colon (73% vs. 22%, p < 0.05) and by histologically well-differentiated type (75% vs. 11%, p < 0.01) in comparison with node-positive cases. All 14 patients with Dukes A tumor undergoing laparoscopic colectomy were free of recurrence during a mean follow-up period of 34 months. The results indicate that all cancers < 2 cm and well-differentiated colon cancers < 3 cm are good candidates for laparoscopic colorectal surgery for cure.     

A case of chronic B cell lymphocytic leukemia with expression of CD8 antigen on leukemic cells

PURPOSE: To determine the toxicity and prognosis of patients with relapsed and refractory diffuse aggressive non-Hodgkin's lymphoma (NHL) who underwent an autologous bone marrow transplant (ABMT) using augmented preparative regimens, treated in a major cooperative group setting, and to examine prognostic factors for outcome. PATIENTS AND METHODS: Ninety-four patients with either chemosensitive (50 patients) or chemoresistant (44 patients) relapse, including 22 who failed induction chemotherapy, were treated with high-dose cyclophosphamide and etoposide with total-body irradiation (TBI) (67 patients) or an augmented carmustine (BCNU), cyclophosphamide, and etoposide (BCV) preparative regimen (27 patients) and an ABMT at 16 Southwest Oncology Group (SWOG) transplant centers. All relapsing patients were required to undergo a minimum of two courses of salvage therapy to determine chemosensitivity before transplant. Overall (OS) and progression-free survival (PFS) were determined and a Cox regression model was used to assess potential prognostic variables. RESULTS: Of the 94 eligible patients, there were 10 (10.6%) deaths before day 50 posttransplant because of infection (six deaths), hemorrhagic alveolitis (three deaths), or bleeding (one death). The median 3-year PFS and OS for the entire group was 33% and 44%. For those with chemosensitive disease the PFS and OS were 42% and 55%, whereas for those with chemoresistant disease the PFS and OS were 22% and 29%. The PFS and OS for those failing induction chemotherapy were 27% and 32%. The relapse rates within the first 3 years for the chemosensitive relapse, chemoresistant, and induction failure groups were 61%, 40%, and 59%, respectively. For both PFS and OS, only disease status at transplant was a significant factor in the multivariate Cox model. CONCLUSION: These results single institutional pilot trials exploring augmented preparative regimens. Patients undergoing transplantation for resistant disease, particularly those failing induction chemotherapy, appear to have an improved prognosis as compared with reports using standard preparative regimens. Therapies other than manipulation of standard preparative regimens appear to be required to decrease relapses following autotransplantation.     

Activity of P-glycoprotein in B-cell chronic lymphocytic leukemia determined by a flow cytometric assay

BACKGROUND: Chemoresistance in some hematologic malignancies has been associated with overexpression of P-glycoprotein, which is encoded by the MDR1 gene (also known as PGY1). However, inconsistencies in data on frequency and clinical relevance of multidrug resistance in B-cell chronic lymphocytic leukemia (B-CLL) may reflect a need for improved techniques to detect this overexpression. PURPOSE: Our purpose was to measure P-glycoprotein activity in peripheral blood cells of B-CLL patients and to analyze possible clinical correlations (disease duration, prior treatment, Rai disease stage, lymphocyte counts, and disease progression). METHODS: P-glycoprotein activity was assayed in peripheral blood cells of 42 consecutive B-CLL patients (22 treated and 20 untreated). We used dual fluorescence in a flow cytometric assay that detects efflux of the fluorescent dye rhodamine 123, which is transported from the cell by the P-glyprotein pump. Leukemia cells were costained with monoclonal antibody Leu12/CD19, and rhodamine 123 efflux was measured. Expression of MDR1 and MDR3 (also known as PGY3) messenger RNA (mRNA) was quantitatively evaluated by polymerase chain reaction (PCR) in 26 cases. RESULTS: Marked rhodamine 123 efflux was observed in 34 (81%) of the 42 cases and was abolished in the presence of multidrug resistance inhibitors. Rhodamine 123 efflux was not associated with Rai stage, lymphocyte counts, duration of disease, or disease progression. Although rhodamine 123-negative cases were about equally distributed among untreated and previously treated patients, the percentage of cells with rhodamine 123 efflux was significantly lower for untreated patients than for those treated with chemotherapy regimens including at least one multidrug resistance-associated drug. MDR1 mRNA was detected in 25 of 26 cases and MDR3 mRNA in all 26. MDR1 mRNA expression was significantly correlated with rhodamine 123 efflux, whereas MDR3 mRNA expression was not significantly correlated; MDR1 and MDR3 mRNA expression was not significantly associated with Rai stage, prior treatment, or disease progresssion. CONCLUSIONS: These findings suggest that P-glycoprotein overexpression in B-CLL is intrinsic rather than acquired and that P-glycoprotein activity is enhanced after exposure to multidrug resistance-associated drugs. This enhanced activity does not seem to be associated with more aggressive disease. Our results also indicate that an assay of P-glycoprotein function combined with PCR is suitable for clinical multidrug resistance screening. IMPLICATIONS: Additional studies are needed to determine whether functional activity of P-glycoprotein, measured by rhodamine 123 efflux, is directly related to clinical drug resistance.     

A case report: CD8 expression in B-cell chronic lymphocytic leukemia (B-CLL). Prognostic significance of the aberrant CD8 expression

We report on a 13-year old girl with severe aplastic anemia and hypertrophic cranial pachymeningitis. She was admitted to our hospital with severe headache and vomiting. A computerized tomographic (CT) scan of the brain on the third day of symptoms showed a hyperdense area in the tentorial region. Magnetic resonance imaging (MRI) showed iso-intensity in the same tentorial region in T1- and T2-weighted images, and gadolinium enhancement of this region suggested a thickened dura mater. Initially, a diagnosis of subdural or subarachnoid hemorrhage was made. Since her platelet count was low (3000/microl) making the patient a poor-risk candidate for surgery, and the area was limited to the dura mater, conservative therapy, including glycerol administration and platelet transfusion, was carried out. Despite clinical improvement 10 days after admission without specific therapy, the iso-intense region on the left side of the tentorial region remained unchanged on MRI. On the other hand, the iso-intense area on the right side of the tentorial region became hyperdense on T1-weighted MRI images and was also enhanced by gadolinium. Cerebrospinal fluid findings were normal except for slightly elevated protein at 62 mg/dl. A diagnosis of hypertrophic cranial pachymeningitis of the tentorial dura mater with hemorrhage on the right side was made. Although hypertrophic cranial pachymeningitis is a rare disease, it must be considered in the differential diagnosis of severe headache in a case of aplastic anemia.     

Chlorambucil synergizes with purine analogs in inducing in vitro cytotoxicity in B-cell chronic lymphocytic leukemia

Combinations of different drug concentrations of CLB + FAMP and CLB + 2-CDA were synergistic in, respectively, 42.9% and 34.8%. At leukemic cell survival < or = 50%, 16.4% and 23.4% of all combinations were synergistic in the 2-CDA and FAMP groups, respectively. A significantly higher mean value of antagonistic interactions was observed in the 2-CDA group (p = 0.037).     

Prognostic significance of the cell cycle inhibitor p27Kip1 in chronic B-cell lymphocytic leukemia

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of resting lymphocytes. The identification of p27(kip1), a cyclin-dependent kinase inhibitor that contributes to cell cycle arrest and represents a link between extracellular signals and cell cycle, prompted us to study p27 protein in the lymphocytes from 88 patients with B-CLL and 32 patients with other chronic B-lymphoproliferative disorders. The expression of p27 protein was higher in B-CLL samples with variations among them. In B-CLL, p27 levels were independent of absolute number of circulating lymphocytes, but strongly correlated with both lymphocyte and total tumor mass (TTM) doubling time. High p27 expression was associated with a poorer overall prognosis. In vitro, there was an increased spontaneous survival of B-CLL cells expressing high p27 levels. Interleukin-4 (IL-4) upregulated p27 levels in B-CLL cells, while fludarabine decreased p27 levels. Thus, our results indicate that p27 may be a valuable kinetic marker in B-CLL by providing instantaneous estimation of the disease doubling time. In addition, these results suggest that there is a link between p27 expression and the ability of CLL cells to undergo apoptosis.