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1.
Blood Cancer J ; 14(1): 2, 2024 01 04.
Article in English | MEDLINE | ID: mdl-38177113

ABSTRACT

MYC oncogene rearrangements (MYC-R) negatively affect survival in patients with Ann Arbor stage III-IV diffuse large B-cell lymphoma (DLBCL), but their impact in limited stage (LS) I-II is unclear. Therefore, we assessed the impact of MYC-R on progression-free survival (PFS) and overall survival (OS) in LS DLBCL patients at the population level. We identified 1,434 LS DLBCL patients with known MYC-R status diagnosed between 2014 and 2020, who received R-CHOP(-like) regimens using the Netherlands Cancer Registry, with survival follow-up until February 2022. Stage I patients with (n = 83, 11%) and without (n = 650, 89%) a MYC-R had similar 2-years PFS (89% and 93%, p = 0.63) and OS (both 95%, p = 0.22). Conversely, stage II DLBCL patients with a MYC-R (n = 90, 13%) had inferior survival outcomes compared to stage II patients without a MYC-R (n = 611, 87%) (PFS 70% vs. 89%, p = 0.001; OS 79% vs. 94%, p < 0.0001). Both single MYC-R (single hit, n = 36) and concurrent BCL2 and/or BCL6 rearrangements (double/triple hit, n = 39) were associated with increased mortality and relapse risk. In conclusion, in stage II DLBCL a MYC-R is negatively associated with survival. In stage I DLBCL, however, survival outcomes are excellent irrespective of MYC-R status. This challenges the diagnostic assessment of MYC-R in stage I DLBCL patients.


Subject(s)
Lymphoma, Large B-Cell, Diffuse , Proto-Oncogene Proteins c-bcl-2 , Humans , Prognosis , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-bcl-6 , Antineoplastic Combined Chemotherapy Protocols , Neoplasm Recurrence, Local , Lymphoma, Large B-Cell, Diffuse/diagnosis , Lymphoma, Large B-Cell, Diffuse/drug therapy , Lymphoma, Large B-Cell, Diffuse/genetics , Doxorubicin/therapeutic use
2.
Am J Hematol ; 99(2): 216-222, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38014799

ABSTRACT

For elderly frail patients with diffuse large B-cell lymphoma (DLBCL), an attenuated chemo-immunotherapy strategy of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-miniCHOP) was introduced as a treatment option as from 2014 onward in the Netherlands. Although R-miniCHOP is more tolerable, reduction of chemotherapy could negatively affect survival compared to R-CHOP. The aim of this analysis was to assess survival of patients treated with R-miniCHOP compared to R-CHOP. DLBCL patients ≥65 years, newly diagnosed in 2014-2020, who received ≥1 cycle of R-miniCHOP or R-CHOP were identified in the Netherlands Cancer Registry, with survival follow-up through 2022. Patients were propensity-score-matched for baseline characteristics. Main endpoints were progression-free survival (PFS), overall survival (OS), and relative survival (RS). The use of R-miniCHOP in DLBCL increased from 2% in 2014 to 15% in 2020. In total, 384 patients treated with R-miniCHOP and 384 patients treated with R-CHOP were included for comparison (median age; 81 years, stage 3-4; 68%). The median number of R-(mini)CHOP cycles was 6 (range, 1-8). The 2-year PFS, OS and RS were inferior for patients treated with R-miniCHOP compared to R-CHOP (PFS 51% vs. 68%, p < .01; OS 60% vs. 75%, p < .01; RS 69% vs. 86%, p < .01). In multivariable analysis, patients treated with R-miniCHOP had higher risk of all-cause mortality compared to patients treated with R-CHOP (HR 1.73; 95%CI, 1.39-2.17). R-miniCHOP is effective for most elderly patients. Although survival is inferior compared to R-CHOP, the use of R-miniCHOP as initial treatment is increasing. Therefore, fitness needs to be carefully weighed in treatment selection.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Lymphoma, Large B-Cell, Diffuse , Humans , Aged , Rituximab , Antibodies, Monoclonal, Murine-Derived/adverse effects , Vincristine/adverse effects , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Doxorubicin/adverse effects , Cyclophosphamide , Prednisone/adverse effects , Treatment Outcome
3.
Blood ; 141(25): 3055-3064, 2023 06 22.
Article in English | MEDLINE | ID: mdl-37001036

ABSTRACT

The objective of this study is to externally validate the clinical positron emission tomography (PET) model developed in the HOVON-84 trial and to compare the model performance of our clinical PET model using the international prognostic index (IPI). In total, 1195 patients with diffuse large B-cell lymphoma (DLBCL) were included in the study. Data of 887 patients from 6 studies were used as external validation data sets. The primary outcomes were 2-year progression-free survival (PFS) and 2-year time to progression (TTP). The metabolic tumor volume (MTV), maximum distance between the largest lesion and another lesion (Dmaxbulk), and peak standardized uptake value (SUVpeak) were extracted. The predictive values of the IPI and clinical PET model (MTV, Dmaxbulk, SUVpeak, performance status, and age) were tested. Model performance was assessed using the area under the curve (AUC), and diagnostic performance, using the positive predictive value (PPV). The IPI yielded an AUC of 0.62. The clinical PET model yielded a significantly higher AUC of 0.71 (P < .001). Patients with high-risk IPI had a 2-year PFS of 61.4% vs 51.9% for those with high-risk clinical PET, with an increase in PPV from 35.5% to 49.1%, respectively. A total of 66.4% of patients with high-risk IPI were free from progression or relapse vs 55.5% of patients with high-risk clinical PET scores, with an increased PPV from 33.7% to 44.6%, respectively. The clinical PET model remained predictive of outcome in 6 independent first-line DLBCL studies, and had higher model performance than the currently used IPI in all studies.


Subject(s)
Lymphoma, Large B-Cell, Diffuse , Neoplasm Recurrence, Local , Humans , Prognosis , Retrospective Studies , Positron-Emission Tomography , Lymphoma, Large B-Cell, Diffuse/diagnosis , Risk Factors , Fluorodeoxyglucose F18
4.
Eur J Nucl Med Mol Imaging ; 49(3): 943-952, 2022 02.
Article in English | MEDLINE | ID: mdl-34476551

ABSTRACT

PURPOSE: MYC gene rearrangements in diffuse large B-cell lymphoma (DLBCL) patients are associated with poor prognosis. Our aim was to compare patterns of 2[18F]fluoro-2-deoxy-D-glucose positron emission tomography computed tomography (PET/CT) response in MYC + and MYC- DLBCL patients. METHODS: Interim PET/CT (I-PET) and end of treatment PET/CT (EoT-PET) scans of 81 MYC + and 129 MYC- DLBCL patients from 2 HOVON trials were reviewed using the Deauville 5-point scale (DS). DS1-3 was regarded as negative and DS4-5 as positive. Standardized uptake values (SUV) and metabolic tumor volume (MTV) were quantified at baseline, I-PET, and EoT-PET. Negative (NPV) and positive predictive values (PPV) were calculated using 2-year overall survival. RESULTS: MYC + DLBCL patients had significantly more positive EoT-PET scans than MYC- patients (32.5 vs 15.7%, p = 0.004). I-PET positivity rates were comparable (28.8 vs 23.8%). In MYC + patients 23.2% of the I-PET negative patients converted to positive at EoT-PET, vs only 2% for the MYC- patients (p = 0.002). Nine (34.6%) MYC + DLBCL showed initially uninvolved localizations at EoT-PET, compared to one (5.3%) MYC- patient. A total of 80.8% of EoT-PET positive MYC + patients showed both increased lesional SUV and MTV compared to I-PET. In MYC- patients, 31.6% showed increased SUV and 42.1% showed increased MTV. NPV of I-PET and EoT-PET was high for both MYC subgroups (81.8-94.1%). PPV was highest at EoT-PET for MYC + patients (61.5%). CONCLUSION: MYC + DLBCL patients demonstrate aberrant PET response patterns compared to MYC- patients with more frequent progression during treatment after I-PET negative assessment and new lesions at sites that were not initially involved. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: HOVON-84: EudraCT: 2006-005,174-42, retrospectively registered 01-08-2008. HOVON-130: EudraCT: 2014-002,654-39, registered 26-01-2015.


Subject(s)
Lymphoma, Large B-Cell, Diffuse , Positron Emission Tomography Computed Tomography , Fluorodeoxyglucose F18 , Gene Rearrangement , Humans , Lymphoma, Large B-Cell, Diffuse/diagnostic imaging , Lymphoma, Large B-Cell, Diffuse/genetics , Lymphoma, Large B-Cell, Diffuse/therapy , Positron Emission Tomography Computed Tomography/methods , Positron-Emission Tomography , Prognosis , Retrospective Studies
6.
Ann Hematol ; 97(2): 255-266, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29209924

ABSTRACT

Burkitt lymphoma is an aggressive B cell malignancy accounting for 1-2% of all adult lymphomas. Treatment with dose-intensive, multi-agent chemotherapy is effective but associated with considerable toxicity. In this observational study, we compared real-world efficacy, toxicity, and costs of four frequently employed treatment strategies for Burkitt lymphoma: the Lymphome Malins B (LMB), the Berlin-Frankfurt-Münster (BFM), the HOVON, and the CODOX-M/IVAC regimens. We collected data from 147 adult patients treated in eight referral centers. Following central pathology assessment, 105 of these cases were accepted as Burkitt lymphoma, resulting in the following treatment groups: LMB 36 patients, BFM 19 patients, HOVON 29 patients, and CODOX-M/IVAC 21 patients (median age 39 years, range 14-74; mean duration of follow-up 47 months). There was no significant difference between age, sex ratio, disease stage, or percentage HIV-positive patients between the treatment groups. Five-year progression-free survival (69%, p = 0.966) and 5-year overall survival (69%, p = 0.981) were comparable for all treatment groups. Treatment-related toxicity was also comparable with only hepatotoxicity seen more frequently in the CODOX/M-IVAC group (p = 0.004). Costs were determined by the number of rituximab gifts and the number of inpatients days. Overall, CODOX-M/IVAC had the most beneficial profile with regards to costs, treatment duration, and percentage of patients completing planned treatment. We conclude that the four treatment protocols for Burkitt lymphoma yield nearly identical results with regards to efficacy and safety but differ in treatment duration and costs. These differences may help guide future choice of treatment.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Burkitt Lymphoma/drug therapy , Cost-Benefit Analysis , HIV Infections/drug therapy , Adolescent , Adult , Aged , Burkitt Lymphoma/complications , Burkitt Lymphoma/economics , Burkitt Lymphoma/mortality , Carmustine/economics , Carmustine/therapeutic use , Cyclophosphamide/economics , Cyclophosphamide/therapeutic use , Cytarabine/economics , Cytarabine/therapeutic use , Etoposide/economics , Etoposide/therapeutic use , Female , HIV Infections/complications , HIV Infections/economics , HIV Infections/mortality , Humans , Ifosfamide/economics , Ifosfamide/therapeutic use , Male , Melphalan/economics , Melphalan/therapeutic use , Methotrexate/economics , Methotrexate/therapeutic use , Middle Aged , Neoplasm Staging , Retrospective Studies , Rituximab/economics , Rituximab/therapeutic use , Survival Analysis
8.
Bone Marrow Transplant ; 51(6): 799-806, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26878656

ABSTRACT

Allogeneic stem cell transplantation (alloSCT) remains the only curative option for CLL patients. Whereas active disease at the time of alloSCT predicts poor outcome, no standard remission-induction regimen exists. We prospectively assessed outcome after cisplatin-containing immune-chemotherapy (R-DHAP) followed by alloSCT in 46 patients (median age 58 years) fulfilling modified European Society for Blood and Marrow Transplantation (EBMT) CLL Transplant Consensus criteria being refractory to or relapsed (R/R) <1 year after fludarabine or <2 years after fludarabine-based immunochemotherapy or R/R with del(17p). Twenty-nine patients received ⩾3 cycles of R-DHAP and sixteen <3 cycles (4 because of disease progression, 8 for toxicity and 4 toxic deaths). Overall rate of response to R-DHAP was 58%, 31 (67%) proceeded to alloSCT after conditioning with fludarabine and 2 Gy TBI. Twenty (65%) remained free from progression at 2 years after alloSCT, including 17 without minimal residual disease. Intention-to-treat 2-year PFS and overall survival of the 46 patients were 42 and 51% (35.5 months median follow-up); del(17p) or fludarabine refractoriness had no impact. R-DHAP followed by alloSCT is a reasonable treatment to be considered for high-risk CLL patients without access or resistance to targeted therapies.


Subject(s)
Cisplatin/administration & dosage , Hematopoietic Stem Cell Transplantation/methods , Leukemia, Lymphocytic, Chronic, B-Cell/therapy , Disease-Free Survival , Hematopoietic Stem Cell Transplantation/mortality , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Middle Aged , Neoplasm, Residual , Risk , Survival Rate , Transplantation Conditioning/methods , Treatment Outcome
9.
Eur J Cancer ; 55: 140-6, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26820684

ABSTRACT

In the past decade, patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL) were treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) therapy. Standard treatment is now changing as a result of deeper understanding of underlying biologic differences of such lymphomas. One of the most powerful predictors of an adverse outcome on R-CHOP therapy is the presence of a MYC gene rearrangement (MYC+ lymphoma). Determination of MYC gene rearrangement by FISH (fluorescent in situ hybridisation) has recently become a standard diagnostic procedure. In this paper, an overview of current literature on MYC function and MYC+ lymphoma patient outcome is presented. Furthermore, we present 26 patients from our tertiary referral centre who were diagnosed with MYC+ lymphoma between 2009 and 2014. In our patient series, we confirm the dismal prognosis of MYC+ lymphoma patients. Intensification of classical chemotherapy does not lead to better overall survival, justifying new treatment modalities. First line therapy should be more specifically targeted against MYC and the genes and proteins that are deregulated by MYC. To this end, the first clinical trial in which MYC+ patients will be offered targeted treatment has recently been launched.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biomarkers, Tumor/genetics , Gene Rearrangement , Lymphoma, Large B-Cell, Diffuse/drug therapy , Proto-Oncogene Proteins c-myc/genetics , Adult , Aged , Female , Genetic Predisposition to Disease , Humans , In Situ Hybridization, Fluorescence , Lymphoma, Large B-Cell, Diffuse/genetics , Lymphoma, Large B-Cell, Diffuse/mortality , Lymphoma, Large B-Cell, Diffuse/pathology , Male , Middle Aged , Molecular Targeted Therapy , Patient Selection , Phenotype , Precision Medicine , Predictive Value of Tests , Survival Analysis , Treatment Outcome
10.
J Cardiovasc Transl Res ; 7(5): 475-82, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24831573

ABSTRACT

Stem cell therapy is a promising strategy in promoting cardiac repair in the setting of ischemic heart disease. Clinical and preclinical studies have shown that cell therapy improves cardiac function. Whether autologous or allogeneic cells should be used, and the need for immunosuppression in non-autologous settings, is a matter of debate. Cyclosporin A (CsA) is frequently used in preclinical trials to reduce cell rejection after non-autologous cell therapy. The direct effect of CsA on the function and survival of stem cells is unclear. Furthermore, the appropriate daily dosage of CsA in animal models has not been established. In this review, we discuss the pros and cons of the use of CsA on an array of stem cells both in vitro and in vivo. Furthermore, we present a small collection of data put forth by our group supporting the efficacy and safety of a specific daily CsA dosage in a pig model.


Subject(s)
Cyclosporine/administration & dosage , Graft Survival/drug effects , Heart Diseases/surgery , Immunosuppressive Agents/administration & dosage , Regeneration/drug effects , Stem Cell Transplantation , Stem Cells/drug effects , Animals , Cell Survival/drug effects , Cyclosporine/adverse effects , Disease Models, Animal , Drug Administration Schedule , Heart Diseases/immunology , Heart Diseases/pathology , Heart Diseases/physiopathology , Humans , Immunosuppressive Agents/adverse effects , Stem Cell Transplantation/adverse effects , Stem Cells/immunology , Swine , Time Factors , Treatment Outcome
11.
Neth J Med ; 71(2): 54-62, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23462052

ABSTRACT

On behalf of the lymphoma and multiple myeloma working parties of the Dutch/Belgian Haemato-Oncology Foundation for Adults in The Netherlands (HOVON), we present a guideline for diagnosis and management of Waldenström's macroglobulinemia (WM). Considering the indolent behaviour and heterogeneous clinical presentation of WM, it is crucial to determine the right indications for treatment, as well as to individualise therapeutic options. There are significant differences from the approach to multiple myeloma or the treatment of other indolent non-Hodkgin lymphomas, and these results cannot always be extrapolated. There is a lack of large clinical trials due to the low incidence of WM. Based on the available data, we provide a practical diagnostic classification, as well as recommendations for first-line therapy and options for treating relapsed disease. Some typical clinical features of WM, such as autoimmune phenomena and 'IgM flare' after rituximab treatment, are highlighted. A more elaborate version of this guideline was published in the 'Nederlands Tijdschrift voor Hematologie' (Dutch Journal for Hematology) September 2012.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Immunologic Factors/therapeutic use , Waldenstrom Macroglobulinemia/diagnosis , Bone Marrow/pathology , Humans , Monoclonal Gammopathy of Undetermined Significance/diagnosis , Monoclonal Gammopathy of Undetermined Significance/therapy , Plasmapheresis , Waldenstrom Macroglobulinemia/therapy
12.
Neth J Med ; 69(10): 422-9, 2011 Oct.
Article in English | MEDLINE | ID: mdl-22058261

ABSTRACT

One of the principal responsibilities of the Chronic Lymphocytic Leukaemia (CLL) Working Party of the Dutch/Belgium Haemato-Oncology Foundation for Adults in the Netherlands (HOVON) is to create up-to-date guidelines for CLL . In this article, the revised guidelines for diagnosis and treatment are summarised. Despite recent expansion in treatment options for patients with CLL , the disease remains incurable in most cases and the optimal treatment approach for several subgroups of patients is still unclear. Therefore, it remains highly important to treat patients within clinical studies as much as possible. In this article, the current studies initiated by the HOVON CLL working party are emphasised.


Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Leukemia, Lymphocytic, Chronic, B-Cell/therapy , Antineoplastic Agents/therapeutic use , Hematopoietic Stem Cell Transplantation , Humans , Netherlands , Recurrence
13.
Leuk Res ; 35(6): 741-9, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21281967

ABSTRACT

Activation of the TNF-related apoptosis-inducing ligand (TRAIL) pathway can induce apoptosis in a broad range of human cancer cells. Four membrane-bound receptors have been identified. TRAIL-R1 and TRAIL-R2 contain a functional death domain; TRAIL-R3 and TRAIL-R4 lack a functional death domain and function as decoy receptors. Flow-cytometric analysis revealed that acute myeloid leukemic (AML) blasts expressed significantly more pro-apoptotic receptors compared to normal blasts. However, about 20% of AML patients highly expressed decoy receptor TRAIL-R3, which was strongly correlated to a shortened overall survival. TRAIL-R3 expression was also high on CD34+/CD38- cells, the compartment that harbors the leukemia initiating stem cell. Expression levels of pro-apoptotic TRAIL receptors were not correlated to the susceptibility for soluble TRAIL, which was generally low (mean level of cell death induction 14%). Cell death could be enhanced by down-modulation of TRAIL-R3, confirming its decoy function on AML blasts. Bypassing of TRAIL-R3 by treatment with antibodies directly targeting TRAIL-R2 resulted in higher rates of induced cell death (max. 80%). In conclusion, AML blasts do express pro-apoptotic TRAIL receptors. However, co-expression of decoy receptor TRAIL-R3 results in significant shortened overall survival. AML blasts could be targeted by anti-TRAIL-R2 antibodies, yielding a new therapeutic option for AML patients.


Subject(s)
Leukemia, Myeloid, Acute/metabolism , Neoplastic Stem Cells/metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand/biosynthesis , Tumor Necrosis Factor Decoy Receptors/biosynthesis , Adolescent , Adult , Aged , Antibodies, Monoclonal/pharmacology , Antibodies, Monoclonal, Humanized , Apoptosis/drug effects , Bone Marrow Cells/metabolism , Bone Marrow Cells/pathology , Cell Line , Cell Line, Tumor , Drug Resistance, Neoplasm/drug effects , Female , GPI-Linked Proteins/biosynthesis , HL-60 Cells , Humans , Kaplan-Meier Estimate , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/pathology , Male , Middle Aged , Neoplastic Stem Cells/pathology , Prognosis , Receptors, TNF-Related Apoptosis-Inducing Ligand/antagonists & inhibitors , Receptors, Tumor Necrosis Factor, Member 10c , TNF-Related Apoptosis-Inducing Ligand/pharmacology , Treatment Outcome , U937 Cells , Young Adult
14.
Immunobiology ; 211(6-8): 619-25, 2006.
Article in English | MEDLINE | ID: mdl-16920500

ABSTRACT

MHC class II molecules presenting MHC class II restricted antigens play an important role in the activation of CD4+ T cells, which are the central orchestrating cells of an immune response. This review focuses on the particular role of MHC class II molecules in tumour immunology. The MHC class II antigen presentation pathway and the expression of MHC class II molecules on tumour cells related to clinical outcome is discussed. Improving the MHC class II tumour antigen presentation pathway, for instance by downregulation of the invariant chain or modulation of HLA-DO expression, offers many opportunities for developing new modalities of immunotherapy.


Subject(s)
Biomarkers, Tumor/metabolism , Histocompatibility Antigens Class II/metabolism , Immunologic Factors/metabolism , Neoplasms/immunology , Animals , Humans , Neoplasms/diagnosis , Neoplasms/metabolism , Prognosis
16.
Haematologica ; 88(4): ECR10, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12681983

ABSTRACT

We present a patient with acute myeloid leukaemia who developed subcutaneously disseminated aspergillosis after allogeneic peripheral stem cell transplantation (PSCT). Disseminated aspergillosis after stem cell transplantation has a high mortality despite treatment with amphotericin B or one of the azoles. Aspergillosis in our patient was refractory to amphotericin B and itraconazole but was successfully treated with caspofungin acetate.


Subject(s)
Aspergillosis/drug therapy , Peptides, Cyclic , Peptides/therapeutic use , Peripheral Blood Stem Cell Transplantation/adverse effects , Antifungal Agents/therapeutic use , Aspergillosis/etiology , Caspofungin , Drug Resistance , Echinocandins , Female , Humans , Leukemia, Myeloid/complications , Leukemia, Myeloid/therapy , Lipopeptides , Middle Aged , Transplantation, Homologous , Treatment Outcome
17.
Clin Exp Immunol ; 99(2): 155-9, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7851005

ABSTRACT

Lymphocyte functional activity was tested in 38 renal transplant recipients receiving induction treatment with various anti-CD3 MoAbs, i.e. OKT3, T3.G2a (an IgG2a anti-CD3 MoAb) or T3.A (an IgA anti-CD3 MoAb of the same idiotype). During treatment with OKT3 and T3.G2a, lymphocyte response to phytohaemagglutinin-P (PHA), as determined with the use of a whole-blood lymphocyte culture technique, decreased significantly. However, during treatment with T3.A PHA response was not affected. Using a conventional lymphocyte culture technique, PHA response was unchanged during treatment with all three MoAbs, indicating that the immunosuppressive effect of OKT3 and T3.G2a is probably dependent upon the presence of MoAb in culture medium and is reversible. In addition, we tested in vitro inhibition of aspecific mitogen- or antigen-induced lymphocyte stimulation by OKT3, T3.A and T3.G2a. It appeared that at low concentrations (< 25 ng/ml) T3.G2a and OKT3 exerted a stronger immunosuppressive effect than T3.A. However, at higher concentrations T3.A, OKT3 and T3.G2a were equally immunosuppressive. We conclude that the immunosuppressive effect of T3.A is caused by blindfolding. At low concentrations T3.G2a exerts its immunosuppressive effect mainly through modulation of the CD3 and/or T cell receptor complex, as a result of interaction with Fc receptors on monocytes. At higher concentrations blindfolding of the CD3/T cell receptor complex may contribute to immunosuppression.


Subject(s)
Antibodies, Monoclonal/therapeutic use , CD3 Complex/immunology , Immunosuppression Therapy/methods , T-Lymphocytes/immunology , Humans , Immunoglobulin A/immunology , Immunoglobulin G/immunology , Kidney Transplantation/immunology , Lymphocyte Activation/immunology , Mitogens/pharmacology , Muromonab-CD3/therapeutic use
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