The immunophenotype of minimally differentiated acute myeloid leukemia (AML-M0): reduced immunogenicity and high frequency of CD34+/CD38- leukemic progenitors

Minimally differentiated acute myeloid leukemia (AML-M0) is a rare FAB subtype (2-3% of AMLs) of poor prognosis. The aim of our study was to characterize AML-M0 expression and regulation of adhesion/costimulatory molecule involved in immune recognition, to test blast in vitro immunogenicity, and to determine the percentage of leukemia progenitor cells. Here, we demonstrate that alloimmune recognition of AML-M0 in primary mixed lymphocyte reaction, as evaluated by IL-2 secretion of responding T cells, is reduced in comparison with more differentiated subtypes (128 +/- 95 pg/ml vs304 +/- 159 pg/ml, P < 0.05). These data are in line with low blast cell expression of major histocompatibility complex (MHC) class II DR molecules, and of the CD28 ligand B7-2, which plays an important role in AML immune recognition. Adhesion/costimulatory molecules were up-regulated by leukemic cell stimulation via CD40, and, although less efficiently, by gamma-IFN; both stimuli improved blast cell immunogenicity. We also demonstrate that AML-M0 have a very high percentage (40% +/- 30) of CD34+/CD38- leukemic clonogenic precursors in comparison with more differentiated AMLs (2.5% +/- 2) or non-leukemic CD34+hematopoietic precursors (1.8% +/- 0.8). Since the presence of a leukemic cell population at an early differentiation stage has been identified as a poor prognostic factor, we conclude that the high frequency of CD34+/CD38- blasts in AML-M0 may converge with already identified poor prognosis factors such as chemotherapy resistance and cytogenetic abnormalities. The clinical implications of AML-M0 impaired in vitroimmunogenicity and a high percentage of CD34+/CD38- blasts will require comparative analysis of additional patients. The increased immunogenicity of blast cells after CD40 triggering provide interesting clues for AML-M0 immunotherapy, that have to be confirmed with an in vivo leukemia model in mice.

A syndrome of peripheral fat wasting (lipodystrophy) in patients receiving long-term nucleoside analogue therapy

OBJECTIVE

To compare body composition, body fat distribution and insulin secretion in patients taking nucleoside reverse transcriptase inhibitor (NRTI) therapy.

DESIGN AND SETTING

Cross-sectional study in three French AIDS clinical centres.

PATIENTS

Forty-three HIV-infected patients on long-term NRTI therapy including stavudine (n = 27) or zidovudine (n = 16) and 15 therapy-naive HIV-infected patients (control group).

MAIN OUTCOME MEASURES

Fat wasting was assessed by physical examination and body composition by bioelectrical impedance. Regional fat distribution was estimated using caliper measurements of skinfold thickness at four sites and evaluated by computed tomography at abdominal and mid-thigh level. Fasting glucose, insulin, C-peptide, triglyceride, cholesterol, free fatty acid, testosterone, follicle stimulating hormone, luteinizing hormone, cortisol levels, CD4 cell count and HIV viral load were determined. Daily total caloric and nutrient intake were evaluated.

RESULTS

The zidovudine group and the control group had similar body composition and regional fat distribution. Stavudine therapy was associated with a significantly lower percentage of body fat (12.9% versus 15.2% in the zidovudine group; P < 0.05), markedly decreased subcutaneous to visceral fat ratio (0.90 +/- 0.63 versus 1.92 +/- 1.34, P < 0.01) and higher mean intake of fat and cholesterol (P < 0.01). Fasting plasma glucose, insulin and C-peptide levels were similar among the three groups. Triglyceride levels were significantly higher in the stavudine group than in the controls (P < 0.05), but did not differ between the stavudine and the zidovudine group or between the zidovudine and the control group. Free fatty acids tended to be higher in the stavudine group but the difference did not reach statistical significance. Lipodystrophy was observed clinically in 17 (63%) patients taking stavudine, and in three (18.75%) patients taking zidovudine after a median time of 14 months. The relative risk of developing fat wasting was 1.95 in the stavudine group as compared with the zidovudine group (95% confidence interval, 1.18-3.22). Five out of 12 patients had a major or mild improvement in their lipodystrophy after stavudine was discontinued.

CONCLUSION

Lipodystrophy may be related to long-term NRTI therapy, particularly that including stavudine.

[Mechanisms of tumor escape from immunologic response]

INTRODUCTION

The rationale for immune control of cancer is now better defined via the immunovirology of transforming viruses, definition of human tumor antigens recognized by T-lymphocytes, and cellular and humoral components of the anticancer response. Nonetheless tumors can escape from immune surveillance. To better define immunomodulation strategies, we describe some of the various strategies developed by transformed cells to evade the immune response.

CURRENT KNOWLEDGE AND KEY POINTS

Both the lack of specific tumor antigen and down-regulation of major histocompatibility complex (MHC) molecule expression hamper recognition of neoplastic cells by T-lymphocytes. In presence of defective expression of ligands for the T-cell co-stimulatory receptors, tumor recognition may lead to the development of tolerance instead of specific cytotoxic activity. Tumor cell counter-attack against effector T-cells has also been described, using either inhibitory cytokines (IL-10), apoptosis induction (via Fas signalling), functional inactivation (disruption of normal CD40/CD40 ligand interactions), or induction of anergy.

FUTURE PROSPECTS AND PROJECTS

Despite the many different mechanisms of tumor escape, the immune system has developed efficient counter-attacks. For instance, natural killer cells may detect and destroy tumor cells that lack class 1 MHC molecules and thus escape from specific T-lymphocyte cytolysis. Moreover, immunogenicity can be restored, at least in vitro, by different means such as tumor cell stimulation by cytokines or CD40, suggesting that therapeutic strategies will soon be developed in order to stimulate an efficient antitumoral immune response.

Comparison of subcutaneous and intravenous interleukin-2 in asymptomatic HIV-1 infection: a randomised controlled trial. ANRS 048 study group

BACKGROUND

Intermittent interleukin-2 therapy for HIV-1 by continuous intravenous infusion leads to sustained increase of CD4 T cells. This method of administration is, however, inconvenient and has limiting toxic effects. We did a randomised study to compare safety and efficacy of antiviral treatment alone or combined with various interleukin-2 regimens in HIV-1-infected patients.

METHODS

94 symptom-free patients, naïve to antiretroviral treatment, with CD4-T-cell counts of 250-550 cells/microL at baseline were randomly assigned zidovudine and didanosine alone (n=26) or combined with interleukin-2 administered intravenously (12 million IU/day, n=22) or subcutaneously (3 million IU/m2 twice daily, n=24) for 5 days, or were given polyethylene-glycol-modified (PEG) interleukin-2 (2 million IU/m2 intravenous bolus, n=22) administered every 2 months from week 2 to week 50 (seven cycles). Safety and immunological and virological results were monitored until week 56.

FINDINGS

CD4-T-cell count increased to higher than baseline by a mean of 564 cells/microL (subcutaneous group), 676 cells/microL (intravenous group), 105 cells/microL (PEG group), and 55 cells/microL (antiretroviral-therapy group, p=0.0001). 68% and 77% of patients in the subcutaneous and intravenous groups, respectively, achieved an 80% increase of CD4 T cells (p<0.001). In these two groups, 50% of patients restored a CD4/CD8-T-cell ratio of more than 1. The groups did not differ significantly for changes in plasma HIV-1 RNA loads throughout the study. The duration of common side-effects of interleukin-2 was shorter in the subcutaneous group, which enabled outpatient treatment. Naïve and memory CD4 T cells, CD28 expression on CD4 and CD8 T cells, and restoration of in-vitro proliferative response to mitogens and recall antigens increased in the intravenous and subcutaneous groups.

INTERPRETATION

Subcutaneous interleukin-2 is a convenient regimen that, as well as intravenous therapy, improves immunological function in HIV-1-infected patients receiving two nucleosides. Larger studies are needed to show whether immunological improvements translate into clinical benefit.

Intensive sequential chemotherapy (ISC 95) with growth factors and blood stem cell support in high-intermediate and high-risk (IPI 2 and IPI 3) aggressive non-Hodgkin's lymphoma: an oligocentric report on 42 patients

We previously reported feasibility and efficacy of a monocentric pilot study of intensive sequential chemotherapy (ISC) in poor-risk aggressive non-Hodgkin's lymphoma (NHL) in patients < 60 years. To validate these results on a large cohort of patients, we designed a new and oligocentric study. After a COP (cyclophosphamide (Cy), vincristine (Vcr), prednisone (Pred) debulking, patients received four courses of high-dose CHOP (Cy, doxorubicin (Doxo), Ver, Pred), with the addition of etoposide and cisplatin during the two last courses. G-CSF was delivered after each cycle, and peripheral blood stem cells (PBSC) were used to support the two last cycles. Total duration of chemotherapy was 13 weeks, with a planned dose-intensity (DI) of 1420 mg/m2/week and 23 mg/m2/week for Cy and Doxo, respectively. Radiotherapy (involved fields) was then delivered for patients with node size > or = 5 cm at diagnosis. Forty-two patients were enrolled in this study; 36 completed the treatment and received 75% or more of the planned DI for both Cy and Doxo. Median duration of grade 4 neutropenia was 14 days (range, 2 to 28) for the regimen as a whole, and median duration of rehospitalization for febrile neutropenia was 18 days (range, 4 to 41). Overall response rate was 83%, with 29 patients (69%) in complete response (CR). Six patients failed to respond and one died of toxicity. With a median follow-up of 22.5 months (range, 10 to 42), the 3-year event-free survival (EFS) is 55% (95% CI, 39-71), while disease-free survival (DFS) is 79% (95% CI, 63-95). Ambulatory ISC is accessible and feasible in an oligocentric study. PBSC allow repeated delivery of high-dose chemotherapy cycles, and result in encouraging CR, EFS, and DFS rates for poor-risk aggressive NHL's patients.

Tumor escape from immune surveillance

The bases for an efficient anti-tumor immune response begin to be better defined. Nonetheless, neoplastic cells develop various strategies to escape immune surveillance, which are discussed here in order to better design the therapeutic possibilities of immune manipulation. The absence of specific tumor antigen as well as the weak expression of major histocompatibility complex (MHC) molecules hinder the recognition of the neoplastic cells by T lymphocytes. The defect of expression by the tumor of the ligands for the T cell activation costimulatory molecules is particularly harmful for the immune response since it induces tolerance. Finally, tumor cells can inactivate effector T lymphocytes through the secretion of inhibitory cytokines, induction of apoptosis or functional inactivation. The multiplicity of the means to oppose an effective anti-tumor response challenges the adaptative mechanisms of the immune system. For example, the natural killer cells target tumor cells not expressing MHC class I molecules. Numerous possibilities of tumor immunogenicity restoration have been demonstrated at least in vitro, such as stimulation of the cancerous cells by CD40 or cytokine treatment, which could lead to several promising therapeutical approaches.

Differential modulation of immune recognition molecules by interleukin-7 in human acute leukaemias

Clinical animal models and in vitro data afford evidence for anti-leukaemia immunity. Many reports have underlined the interest of interleukin-7 (IL-7) use in cancer and its pivotal role in immune recognition. This cytokine, initially identified as a B cell growth factor, enhances the anti-tumour properties of immune effector cells via T lymphocyte activation, increased specific cytotoxicity and cytokine secretion. Nonetheless, few data are available regarding the effect of IL-7 on the expression at the leukaemia cell surface of molecules involved in the immune response, which defective expression could induce tolerance or anergy. This prompted us to study the effects of IL-7 on 20 cases of acute myeloid leukaemia (AML) and 9 cases of lymphoid leukaemia (ALL), in comparison with gamma-interferon, a potent inducer of immune regulation molecule expression. In AML and ALL, IL-7 increased MHC class I molecule expression, while class II molecules were weakly modified. The expression of the tumour necrosis factor family members CD40 and Fas/CD95, together with the adhesion molecules ICAM-1/CD54 and CD58/LFA-3, was also increased in both types of leukaemia. The IL-7 was an efficient inducer of B7-2/CD86 expression in AML and ALL, while increased expression of B7-1/CD80 was only observed in AML. In the corresponding, co-cultured T lymphocyte population, IL-7 more particularly increased B7-1/CD80 and CD58/LFA-3 expression. Finally, pre-incubation of leukaemic cells with IL-7 increased the proliferation of responding, normal allogenic T lymphocytes and their secretion of gamma-IFN and IL-2 in mixed the lymphocyte-tumour reaction. We concluded that IL-7 is efficient at increasing the membrane expression of molecules which are central for the development of the immune response, and at improving allogenic immune recognition. The clinical implications of such data require further in vivo investigation.

Positive selection of CD34+ peripheral blood progenitor cells in patients with low-grade lymphoid malignancies and bone marrow involvement

PURPOSE

16 patients with low-grade lymphoid malignancies and bone marrow involvement were transplanted with selected CD34 positive Peripheral Blood Progenitor Cell (PBSC) prepared from autologous aphereses.

PATIENT AND METHODS

All but one patients were mobilized with a combination of chemotherapy (including high-dose cyclophosphamide and VP16 or adriamycin, aracytin with cysplatyl) and recombinant human Granulocyte Colony-Stimulating Factor (rhG-CSF).

RESULTS

A median of 3 (range, 1 to 9) aphereses yielded 15.35 x 10(6) CD34+ cells/kg (range, 4.45 to 70.88). A median of 5.01 x 10(6) adsorbed CD34+ cells/kg (range 2.01 to 24.13) was obtained after selection (median purity: 86%; range, 59-99%). The CD34 PBSC were infused one day after either one of two conditioning regimens: 11 patients received the association of cyclophosphamide (120 mg/kg) and TBI (8Gy), and 5 patients received the BEAM regimen. No recombinant hematopoietic growth factor was used after cell reinfusion. Median days to 0.5 x 10(9)/l neutrophils and 50 x 10(9)/l platelets were 13 (range, 9 to 18) and 16 (range, 11 to 35), respectively. The median number of red blood cell (RBC) unit transfusions was 4 (range, 0 to 10). The median number of platelet transfusions was 3.5 (range, 0 to 8). No individual received backup PBSC, nor required platelet transfusion beyond 3 months post-transplant.

CONCLUSION

This study confirms the feasability of using blood CD34 cells to support hematopoietic recovery after myelo-suppressive or myelo-ablative regimens, in patients with low-grade NHL.

Isolated, chronic, epilepsia partialis continua in an HIV-infected patient

BACKGROUND

The characteristic clinical feature of epilepsia partialis continua (EPC) is chronic focal myoclonus, usually involving the distal part of one extremity. A variety of pathogenetic factors have been implicated in EPC. In children, the most common cause is Rasmussen encephalitis; in adults, it is vascular disease or tumor involving the sensorimotor cortex. Epileptic seizures are a relatively common manifestation of central nervous system involvement in patients infected with human immunodeficiency virus (HIV), but, to our knowledge, isolated, chronic EPC has not been previously reported.

OBJECTIVE

To describe a case of typical EPC in a patient infected with HIV.

DESIGN AND SETTING

Case report from an epilepsy center.

PATIENT

A 58-year-old man infected with HIV had continuous myoclonus that involved the right arm and was associated with intermittent motor seizures. The electroencephalographic findings were normal at the onset of the symptoms, but left central theta rhythm appeared later. Serial magnetic resonance imaging scans obtained over a 3-month period showed a progressively increasing left rolandic T2-weighted hypersignal. Histologic study of a stereotactic biopsy specimen demonstrated inflammation characterized by perivascular mononuclear cell infiltration. The only detectable cause was HIV infection. Immunocytochemical tests ruled out JC virus. Neuropsychological testing showed no evidence of cognitive impairment. An electroencephalographic-electromyographic "back-averaging" study showed a reproducible transient left biphasic complex preceding the bursts by about 30 milliseconds on the C3 and F3 electrodes, thus demonstrating that the myoclonus was of cortical origin. High-dose corticosteroid (prednisone, 100 mg/d) and anti-HIV- 1 therapy led to marked radiological and clinical improvement. Infection with HIV enhances the risk of seizures, but, to our knowledge, this is the first reported case of "inflammatory" EPC.

CONCLUSIONS

The present case suggests that the possibility of central nervous system involvement by HIV-1 should be taken into account in the diagnostic workup of patients with EPC. This case also indicates that treatment can be effective.

A randomized trial of three maintenance regimens given after three months of induction therapy with zidovudine, lamivudine, and indinavir in previously untreated HIV-1-infected patients. Trilège (Agence Nationale de Recherches sur le SIDA 072) Study Team

BACKGROUND

The long-term effectiveness of potent three-drug antiretroviral regimens for the treatment of human immunodeficiency virus type 1 (HIV-1) infection is limited by problems related to compliance and tolerability. We investigated whether two-drug maintenance therapy would suppress viral replication after a three-month period of aggressive triple-drug induction therapy.

METHODS

A total of 378 HIV-1-infected adults who had not received previous antiretroviral treatment received three months of induction therapy consisting of 300 mg of zidovudine every 12 hours, 150 mg of lamivudine every 12 hours, and 800 mg of indinavir every 8 hours. The 279 patients in whom the plasma HIV-1 RNA titer fell below 500 copies per milliliter after two months of triple-drug therapy, and who completed the induction phase, were randomly assigned at month 3 to one of the following three open-label maintenance regimens: zidovudine, lamivudine, and indinavir; zidovudine and lamivudine; or zidovudine and indinavir. The primary end point was an increase in HIV-1 RNA levels to 500 copies or more per milliliter during the maintenance phase.

RESULTS

The proportion of patients who reached the primary end point was significantly higher among patients receiving zidovudine plus lamivudine (29 of 93 patients, P<0.001) or zidovudine plus indinavir (21 of 94, P=0.01) than among patients receiving continued triple-drug therapy (8 of 92). This higher failure rate in the groups treated with the two-drug maintenance regimens was also observed in the subgroup of patients with maximally suppressed HIV-1 RNA (below 50 copies per milliliter) at the time of randomization to maintenance therapy.

CONCLUSIONS

In HIV-1-infected adults not previously treated with antiretroviral drugs whose plasma HIV-1 RNA levels fell below 500 copies per milliliter after three months of induction therapy with zidovudine, lamivudine, and indinavir, two-drug maintenance therapy was less effective in sustaining a reduced viral load than continued three-drug therapy.

[Fetal thymic hypoplasia diagnosed after interruption of pregnancy for HIV infection treated with tritherapy]

We report an autopsy case of a malformed fetus with thymic hypoplasia. The autopsy was performed after therapeutic termination in the second trimester of pregnancy. The HIV-1 infected mother had received 3 antiviral agents and treatment for opportunistic infections.

Second neoplasms following high-dose chemotherapy and autologous stem cell transplantation for malignant lymphomas: a report of six cases in a cohort of 171 patients from a single institution

High dose chemotherapy with autologous stem cell transplantation (ASCT) is increasingly used in the treatment of patients with lymphoma. As previously shown with conventional treatments, second neoplasms are emerging as a long term complication of the procedure. In this study, we investigate the incidence of second neoplasm in a cohort of 171 patients treated with BEAM or BEAC regimens for Hodgkin's disease (n = 62) and non-Hodgkin's lymphomas (n = 109) followed up for a median of 52 months post ASCT. Six patients developed six second malignancies 12 to 105 months after ASCT: fibrolamellar carcinoma of the liver, malignant fibrous histiocytoma, pancreatic carcinoma, squamous cell carcinoma of the lung, invasive carcinoma of the vulva and acute myelogenous leukemia. The cumulative actuarial risk for developing second malignancy is 16.7% (95% confidence interval: 5.9-39.3%) 13 years after transplant. The age-adjusted incidence of cancer in the study group is 4.1 times higher than that of primary cancer in the general population. These data confirm that ASCT recipients are at increased risk of later malignancies. This complication adds significant morbidity and mortality to the transplant process and therefore, needs to be taken into account in long term evaluation of new strategies which involve early intensification in the treatment of lymphomas.

[Hodgkin's disease in patients infected with the human immunodeficiency virus]

INTRODUCTION

Hodgkin's disease in patients infected by the human immunodeficiency virus (HIV) is still not part of the definition of acquired immune deficiency syndrome. Nonetheless, this entity has a particular presentation when compared to the disease occurring in immune-competent patients.

CURRENT KNOWLEDGE AND KEY POINTS

Increased frequency (> 75%) of advanced anatomical stages and extranodular localizations (Ann Arbor system stages III and IV) has been outlined in HIV-infected patients. Mediastinal involvement is more unusual in immunocompromised than in immune-competent patients. The presence of B symptoms (fever, weight loss, nocturnal sweats) is very frequent. Finally, the predominance of mixed cellularity (type 3) characterizes Hodgkin's disease in immunocompromised patients. Due to either the immunodeficiency, antiretroviral treatments, poor hematological tolerance in response to chemotherapy, or to advanced anatomical stages, disease management may be hampered. Current therapeutical approaches often obtain complete remission; however, some deaths are still related to the disease progression to acquired immune deficiency syndrome.

FUTURE PROSPECTS AND PROJECTS

From these observations, Hodgkin's disease management in HIV-infected patients relies on therapeutical approaches similar to those used for non infected patients, with some specific recommendations. Chemotherapy should be conducted in the shortest time in order to minimize chemotherapy-induced immunosuppression. Simultaneous use of antiretroviral treatment and reinforced opportunistic infection prophylaxis are of pivotal importance. Finally, the use of hematopoietic growth factors appears to be safe regarding viral replication, but still requires further evaluation.

Anti-GM-CSF monoclonal antibody therapy for refractory acute leukemia

Several phase I trials and pilot studies using Monoclonal Antibody (MoAb) have been performed in B-cell neoplasms, but this approach has not until now been extensively tested in myeloid leukemias. Recently, we evaluated the use of anti-Granulocyte-Macrophage Colony-Stimulating Factor MoAb (Anti-GM-CSF MoAb) in acute myeloid leukemia (AML). Eight patients fulfilled inclusion criteria and received a single course of Anti-GM-CSF MoAb infusion during 5 to 15 days. Anti-GM-CSF MoAb was well tolerated and was detectable in pharmacokinetics studies. Using Human Anti-Rat Antibodies (HARA), we also observed an immunological response to the MoAb. Despite sufficient levels detected in the serum and biological activity of Anti-GM-CSF MoAb in vivo, no anti-leukemic effect was noted, except for one patient who had a decrease of 50% in the marrow blast cell mass. These observations indicate that leukemic proliferation in vivo involves a complex network spanning many mechanisms, and inhibition of leukemia is not effective if only one of these key targets is attacked. The development of these new approaches may be more effective in the future.

Role of induction chemotherapy and bone marrow transplantation in adult lymphoblastic lymphoma: a report on 62 patients from a single center

OBJECTIVE

To describe the outcome of an unselected large series of patients with lymphoblastic lymphoma (LBL) treated in a single institution.

PATIENTS AND METHODS

Sixty-two patients were treated between 1980 and 1992. Induction chemotherapy (CT) to achieve complete response (CR) was: French Multicenter Acute Lymphoblastic Leukemia (ALL) protocols (38), non-Hodgkin's Lymphoma (NHL) protocols (20). Thirty patients underwent transplant after achieving CR (allogeneic 12; autologous 18).

RESULTS

Forty-six patients (74%) achieved CR and 16 (26%) failed to respond. The patients who received an ALL induction had an 89% CR rate, while the CR rate was 52% in patients who received a NHL-like regimen. With a median follow-up of 93 months (range 36-187), the actuarial overall survival (OS) rate for all patients is 49% at five years and 41% at 10 years, and the actuarial event-free survival (EFS) rate is 45% and 37%. OS and EFS in the grafted population are, respectively, 60% and 56% at five years. Our results also show a trend toward a longer OS in allografted group.

CONCLUSIONS

ALL induction therapy is more effective than the NHL-like regimen for augmenting the CR rate. Autologous or allogeneic transplantation should be considered as consolidation therapy in high-risk group patients.

Clinical and economic comparison of lenograstim-primed blood cells (BC) and bone marrow (BM) allogeneic transplantation

The study presented is a clinical and economic comparison of bone marrow (BM) and blood cells (BC) allogeneic transplantation. We performed a case-control study to compare 17 patients receiving allogeneic BC transplant in a pilot study to an historical group of 17 patients allografted with BM. We evaluated the clinical outcomes and the direct medical costs of transplantation from conditioning regimen until day 100 by detailed observation of patients' medical records. Patients in the BC group received a median of 8 x 10(6)/kg CD34+ cells (1.58-29.1) and 266 x 10(6)/kg CD3+ cells (128-469). All patients had neutrophil engraftment with a median of 14 days in the BC group vs 19 days in the BM group (P < 0.05). The Kaplan-Meier estimation of the median number of days to a platelet count of > 25 x 10(9)/l, independent of platelet transfusion, was significantly shorter in the BC group (15 (9-74)) compared with the BM group (25 (15-45)). Acute graft-versus-host disease (AGVHD) of grade > or = 2 was not significantly different between the two groups. Patients treated with BC presented a US$16,134 decrease in the cost of the first 100 days (29%, P = 0.006). Our comparison suggested that platelet reconstitution and total costs were in favor of the BC group.

Regulation of CD80/B7-1 and CD86/B7-2 molecule expression in human primary acute myeloid leukemia and their role in allogenic immune recognition

Clinical data and animal models afford evidence for anti-leukemia immunity in humans, but the interactions critical for blast cell recognition are unresolved. Expression of B7 molecules by antigen-presenting cells (APC) provides co-stimulatory signals to T lymphocytes via CD28 and CTLA-4 which prevent the induction of alloantigen-specific tolerance. Conversely, expression of CD40 ligand by stimulated T cells activates APC via CD40. In human hematological B cell malignancies (follicular lymphoma and chronic lymphocytic leukemia), the defect in alloantigen presentation of tumoral cells can be repaired by up-regulation of B7 and other co-stimulatory molecules via CD40. We studied the role of B7 molecules in alloimmune recognition and the various ways to improve the antitumoral response on peripheral blood leukemic cells from 20 patients with a diagnosis of primary acute myeloid leukemia (AML). We focused on myelo/monocytic M4/M5 French-American-British classification subtypes which are considered as the neoplastic counterpart of normal monocytes, a prototypic APC. In one-way mixed lymphocyte reaction of CD4+ T cells against leukemic cells, differences in B7-1, B7-2 or CD40 expression by AML cells did not induce specific cytokine secretion; interleukin (IL)-2 and interferon (IFN)-gamma were detected but not IL-4, corresponding to a Th1 pattern. Blockade experiments showed that proliferation and IFN-gamma secretion only partially depended on B7 molecules, which in contrast had a pivotal role in IL-2 synthesis. In contrast with murine models which suggest a pivotal role for CD80/B7-1 in the immune response against AML, our data support a greater role for CD86/B7-2, in line with the baseline expression of CD86/B7-2 and lack of CD80/B7-1 on most M4/M5 AML cells. AML cell stimulation via CD40: (1) significantly improved IL-2 secretion but not proliferation of responding T lymphocytes, (2) increased CD54/ICAM-1 expression in three quarters of cases, (3) failed in most cases to induce CD40-specific CD80/B7-1 up-regulation, and (4) had a weak effect on CD86/B7-2 expression. These data contrast with the very efficient up-regulation of both B7 co-stimulatory molecule expression and tumoral cell alloimmune recognition following CD40 stimulation in B cell malignancy models. The role of the defective B7 molecule up-regulation by the CD40 pathway in inefficient tumor immunogenicity of primary AML cells has to be further investigated, in particular using transfection experiments of CD80/B7-1-deficient AML cell lines. From our in vitro data we conclude that B7 molecules play an important role in the alloimmune surveillance of AML as suggested by the high B7 molecule dependency of IL-2 secretion. Nonetheless, the contribution of B7 molecules to alloimmune T cell proliferation against primary AML cells in human and the way to improve it--regulation via CD40 in particular--differ from B cell malignancies and murine models, suggesting the requirement for specific strategies in the development of antitumor immunity.

Clinical and biological effects of gamma interferon and the combination of gamma interferon and interleukin-2 after autologous bone marrow transplantation

Interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) have shown synergistic immunomodulatory and anti-tumor effects in preclinical studies. The present study was designed to assess the effects of the combination of these cytokines after autologous bone marrow transplantation (ABMT). Ten patients received rIFN-gamma alone and 13 patients the combination of rIFN-gamma + rIL-2. Patients received transplants because of lymphoma (10 patients), acute leukemia (3 patients) or solid tumors (10 patients). Immunotherapy was started at a median of 67 days after ABMT. All patients received either 5 x 10(6) (8 pts) or 10 x 10(6) IU/m2 (16 pts) rIFN-gamma by subcutaneous injection 3 times weekly for 14 weeks. rIL-2 therapy consisted of 5 cycles of continuous intravenous infusion of 12 x 10(6) IU/m2/day starting 1 week after administration of rIFN-gamma. In the rIFN-gamma group, toxicity was mild and some biological changes were seen (NK/LAK activation, increase of phagocytosis and of NBT reduction). The combination of rIFN-gamma with rIL-2 did not increase the usual rIL-2 toxicity. NK/LAK cytotoxicity was strongly activated after the first cycle of rIL-2 and was maintained until the end of therapy. Granulocyte chemotaxis was defective after cycle 1 but recovered thereafter. We conclude that the administration of rIFN-gamma + rIL-2 is feasible after ABMT. Our data suggest that the combination may have prolonged the immunologic activation provided by rIL-2 and some improvement of the deleterious effects of rIL-2 on granulocyte functions was achieved. Controlled studies are warranted to assess the impact of this strategy on biological response and patient outcome.

Early and fatal immune haemolysis after so-called 'minor' ABO-incompatible peripheral blood stem cell allotransplantation

A 38-year-old man, blood group A+, was allotransplanted for multiple myeloma from his fully matched sister, blood group O+. Anti-A antibodies IgG and IgM titres of the donor were low. Allogeneic peripheral blood stem cells were harvested by leukapheresis after subcutaneous administration of G-CSF. Rapid engraftment occurred since 5.6 x 10(9)/l leukocytes were achieved on day +9 post-transplant. At this time a severe immune haemolytic syndrome occurred and direct antiglobulin test was positive (IgG and C3d). Elution showed an anti-A specificity. Evolution was rapidly unfavourable related to multiorgan failure. The patient died on day +20 post-transplant.