The CD40-ligand stimulates T-lymphocytes via the neutral sphingomyelinase: a novel function of the CD40-ligand as signalling molecule

Recent results suggest an activation of T-lymphocytes via the CD40L implying a dual function of this ligand involved in the activation of both B- and T-lymphocytes [1-4]. Here, we provide evidence that activation of T-lymphocytes via CD40L results in activation of a neutral but not an acidic sphingomyelinase correlating with a consumption of sphingomyelin and a release of ceramide. Activation of the neutral sphingomyelinase by the CD40L seems to involve a novel signalling cascade since it is independent of CD40L induced protein kinase activation or association of the neutral sphingomyelinase with the CD40L.     

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.     

Chronic lymphocytic leukemia B cells can express CD40 ligand and demonstrate T-cell type costimulatory capacity

Chronic lymphocytic leukemia (CLL) is characterized by a clonal expansion of CD5(+) B cells in the peripheral blood. Associated immune aberrations include abnormal Th-cell function and pathogenic autoantibodies. Under most circumstances, CLL B cells do not proliferate in culture and express a limited repertoire of surface antigens, including CD19, CD20, CD23, CD27, CD40, and CD70. In this report, we demonstrate that freshly isolated B cells from a subset of CLL cases constitutively express CD40 ligand (CD40L, CD154), a member of the tumor necrosis factor family which is normally expressed by activated CD4(+) T cells and mediates T-cell-dependent B-cell proliferation and antibody production. The degree of CD40L expression varied considerably among the CLL cases examined. CD40L was detected in purified CLL B cells by immunofluorescence flow cytometry, by RT-PCR, and by immunoprecipitation. To demonstrate that CD40L in the CLL B cells is functional, we used irradiated CLL cells to stimulate IgG production by target, nonmalignant B cells in coculture. The CLL B cells induced IgG production by normal B cells to a similar degree as did purified T cells in a process which was partially inhibited by monoclonal antibody to CD40L. This is one of the first reports of CD40L expression in a B-cell tumor. The data suggest that CD40L in the tumor cells may be a factor in the generation of pathologic antibodies by normal B cells in some patients with CLL.     

Sudden death in a patient with chronic lymphocytic leukemia

The authors describe a 51-year-old man with chronic lymphocytic leukemia who presented with respiratory distress and then died suddenly while in hospital. Autopsy revealed pulmonary leukostasis and a large intracardiac mass containing mostly mature lymphocytes and fibrin. Although leukostasis and lymphocyte thrombi have been described (albeit rarely) in chronic lymphocytic leukemia, an intracardiac "clot" has not. It seems plausible that this intracardiac mass caused the patient's death.     

Chlorambucil in chronic lymphocytic leukemia: mechanism of action

Chronic lymphocytic leukemia (CLL) is the most common leukemia in Western countries but the clinical presentation and rate of disease progression are highly variable. When treatment is required the most commonly used therapy is the nitrogen mustard alkylating agent, chlorambucil (CLB), with or without prednisone. Although CLB has been used in the treatment of CLL for forty years the exact mechanism of action of this agent in CLL is still unclear. Studies in proliferating model tumor systems have demonstrated that CLB can bind to a variety of cellular structures such as membranes, RNA, proteins and DNA; however, DNA crosslinking appears to be most important for antitumor activity in these systems. In addition, a number of different mechanisms can contribute to CLB resistance in these tumor models including increased drug metabolism, DNA repair and CLB detoxification resulting from elevated levels of glutathione (GSH) and glutathione S-transferase (GST) activity. However, unlike tumor models in vitro, CLL cells are generally not proliferating and studies in CLL cells have raised questions about the hypothesis that DNA crosslinking is the major mechanism of antitumor action for CLB in this disease. CLB induces apoptosis in CLL cells and this appears to correlate with the clinical effects of this agent. Thus, alkylation of cellular targets other than DNA, which can also induce apoptosis, may contribute to the activity of CLB. Alterations in genes such as p53, mdm-2, bcl-2 and bax which control entry into apoptosis may cause drug resistance. Loss of wild-type p53 by mutation or deletion occurs in 10 to 15% of CLL patients and appears to correlate strongly with poor clinical response to CLB. The induction of apoptosis by CLB is paralleled by an increase in P53 and Mdm-2 but this increase in not observed in patients with p53 mutations indicating that with high drug concentrations CLB can produce cell death through P53 independent pathways. The level of Mdm-2 mRNA in the CLL cells is not a useful predictor of drug sensitivity. In addition, although Bax and Bcl-2 are important regulators of apoptosis and the levels of these proteins are elevated in CLL cells compared with normal B cells, the levels of Bax and Bcl-2, or the Bax:Bcl-2 ratio, are not important determinants of drug sensitivity in this leukemia. Finally, whereas CLB and nucleoside analogs may produce cell death in CLL by a P53 dependent pathway other agents, such as dexamethasone or vincristine, may act through P53-independent pathways.     

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.     

Intussuception as a complication of chronic lymphocytic leukemia

The case of a 58-year-old man with chronic lymphocytic leukemia (B-cell type) who later developed an intussuception of the small intestine due to a tumor is described. The histopathological findings of the removed tumor were compatible with those of diffuse small lymphocytic lymphoma (B-cell type). The residual tumor became smaller with CHOP therapy. It is considered that CLL cell infiltration into the small intestine resulted in intussuception. Since many tumors and lymphomas can form polypoid lesions causing an intussuception. This is a possible complication of CLL and it could occur even when the WBC count is well controlled.     

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.     

Chemotherapy-induced myocardial necrosis in a patient with chronic lymphocytic leukemia

Cardiac toxicity following the administration of chemotherapeutic agents is well documented. Vinca alkaloids, as well as high-dose cyclophosphamide, have been associated with myocardial ischemia. The present report describes a case of acute myocardial infarction occurring in a patient with no antecedent cardiac history who received both vincristine and conventional chemotherapeutic doses of cyclophosphamide for the treatment of chronic lymphocytic leukemia. Physicians should possess a heightened awareness of this potentially serious complication.     

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.     

Total hip arthroplasty in patients who have chronic lymphocytic leukemia

Twenty patients who had chronic lymphocytic leukemia underwent 25 elective primary total hip arthroplasties at the Mayo Clinic. No patient had a postoperative prosthetic infection. No patient had an intraoperative or postoperative hemorrhagic complication. One patient had a revision for aseptic loosening. After an average follow-up period of 4.6 years, there were 84% good and excellent results. It is concluded that patients who have early-stage chronic lymphocytic leukemia may not be at increased risk for major perioperative or postoperative complications in total hip arthroplasty. The surgeon must remain vigilant for postoperative complications, but satisfactory clinical results can be obtained in this patient population.     

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.     

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.     

Serum levels of soluble CD23, but not soluble CD25, predict disease progression in early stage B-cell chronic lymphocytic leukemia

Serum levels of the soluble forms of CD23 (sCD23) and CD25 (sCD25) were prospectively analyzed with respect to their prognostic relevance in early stage B-cell chronic lymphocytic leukemia (B-CLL). SCD23 and sCD25 levels were determined in 105 patients with newly diagnosed B-CLL (Binet stage A). In 93 of the patients, these levels were correlated with other already established indicators for risk of disease progression, including the histologic pattern of bone marrow infiltration, lymphocyte doubling time (LDT), and the serum level of thymidine kinase (TK). High serum levels of both sCD23 and of sCD25 were associated with a diffuse bone marrow infiltration, a LDT < or = 12 months, and elevated (>5 U/L) serum TK, respectively. Moreover, examination of the clinical course of 76 untreated patients showed that high levels of sCD23, but not of sCD25, at initial diagnosis were linked with disease progression. Furthermore, in a stepwise Cox regression model, high levels of sCD23 and a short LDT were shown to be strong predictors of progressive disease within the first year of disease presentation. Therefore, it appears to be justified to incorporate sCD23 levels into the risk profile of early stage B-CLL and to take them into account for stratification in risk-adapted treatment strategies.     

Demonstration of functional CD40 in B-lineage acute lymphoblastic leukemia cells in response to T-cell CD40 ligand

Because activated T cells were previously shown to induce proliferation of human normal B-cell precursors (BCP) via the CD40 pathway, we investigated the effects of T cells on leukemic blasts isolated from patients with B-lineage acute lymphoblastic leukemia (BCP-ALL). An anti-CD3 activated human CD4+ T-cell clone was found to induce significant call proliferation in four of nine BCP-ALL samples analyzed. In one of these cases, the T-cell effect was clearly dependent on interaction between CD40 and its ligand. Accordingly, a more thorough analysis was performed on this particular leukemia (case 461, adult early pre-B-ALL, mBCR+, Philadelphia+, i(9q)+). Thus, autologous CD4+ T cells isolated from the patient were also able to induce CD40-dependent proliferation of the leukemic blasts. Analysis of the phenotype after coculture showed that, among the CD19+ cells, a proportion gradually lost expression of CD10 and CD34, whereas some cells acquired CD23. In addition, and in contrast with normal BCP, activated T cells promoted maturation of a subset of the case 461 leukemic cells into surface IgM+ cells. The leukemic origin of the cycling and the maturing cells was assessed by the presence of i(9q), a chromosomal abnormality associated with this leukemia and evidenced by fluorescence in situ hybridization. Taken together, these results show that leukemic BCP can be activated via CD40 but that not all cases display detectable stimulation in response to T cells despite their expression of CD40. In addition, the present data suggest that CD4+ T cells could potentially play a role in the physiology of BCP-ALL.     

Advances in the treatment of chronic lymphocytic leukemia (CLL)

CLL is a chronic lymphoproliferative disorder which is characterized by the proliferation of a CD5 positive B cell clone. At diagnosis most patients are in early stage of the disease (stage A). It is well established that an early treatment in stage A is not associated with a survival advantage. Therefore, the disease should be treated only when signs of progression are present. The standard initial therapy is chlorambucil +/- prednisone. By this treatment remissions (mostly partial remissions) are achieved in about half of the patients. Fludarabine, a purine analogue, is more effective than chlorambucil as initial treatment (75% remissions, 27% complete remissions, 33 months progression free survival). However, the overall survival is not prolonged when compared to chlorambucil treatment. Fludarabine has a high efficacy in patients with recurrent disease, in particular in those who are resistant to alkylating agents. The allogeneic and autologous stem cell transplantation is an experimental treatment which may be indicated in younger patients who show a response to conventional treatment. With both procedures hematological remissions are frequently achieved and in some of the patients long lasting molecular remissions were obtained. Currently, it is unknown whether patients can be cured by stem cell transplantation and longer follow-up will be necessary to clarify this question. Monoclonal B-cell antibodies are effective in vivo and partial remissions can be obtained in chemotherapy refractory patients. Antibodies have a high efficacy in clearing lymphoma cells from peripheral blood and bone marrow but are less effective on the organomegaly.     

Lymphopenic effect of carbamazepine in a patient with chronic lymphocytic leukemia

OBJECTIVE: To report a dramatic and reproducible suppressive effect of carbamazepine on circulating lymphocytes in an elderly woman with chronic lymphocytic leukemia. CASE SUMMARY: An elderly woman taking phenytoin for a stroke-associated seizure disorder had lymphocyte count of 28,800 x 10(6) cells/L. Speculating an unusual lymphadenopathic effect of the phenytoin therapy, carbamazepine therapy was substituted. After 15 weeks of carbamazepine treatment, the lymphocyte count declined to 3200 x 10(6) cells/L. Because of severe diarrhea, carbamazepine therapy was stopped and phenytoin therapy was reinstituted. At the end of 4 months of phenytoin treatment, the lymphocyte count had increased to 23,200 x 10(6) cells/L. Phenytoin therapy was discontinued and carbamazepine therapy was begun. The lymphocyte count decreased to 10,700 x 10(6) cells/L. Severe diarrhea recurred and phenytoin treatment was reinstituted. Over 12 days the lymphocyte count increased to 28,900 x 10(6) cells/L. Phenytoin therapy was stopped and valproic acid therapy was started. The lymphocyte count continued to increase during valproic acid therapy, reaching a peak of 114,300 x 10(6) cells/L. DISCUSSION: In this patient with chronic lymphocytic leukemia, carbamazepine therapy had a significant and reproducible lymphopenic effect that was readily reversible upon discontinuation of the drug. Unfortunately, this effect was associated with severe diarrhea, preventing further attempts at exploiting this potentially beneficial action. CONCLUSIONS: Carbamazepine had a reproducible suppressive effect on lymphocyte counts in an elderly patient with chronic lymphocytic leukemia. This unique observation raises the possibility that carbamazepine therapy may have a useful effect in patients with chronic lymphocytic leukemia.