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Biomedical subjects

David Ghez

Publications and source records attributed to David Ghez.

9 recordsLinked to original sources

Neuropilin-1 is involved in human T-cell lymphotropic virus type 1 entry.

Human T-cell lymphotropic virus type 1 (HTLV-1) is transmitted through a viral synapse and enters target cells via interaction with the glucose transporter GLUT1. Here, we show that Neuropilin-1 (NRP1), the receptor for semaphorin-3A and VEGF-A165 and a member of the immune synapse, is also a physical and functional partner of HTLV-1 envelope (Env) proteins. HTLV-1 Env and NRP1 complexes are formed in cotransfected cells, and endogenous NRP1 contributes to the binding of HTLV-1 Env to target cells. NRP1 overexpression increases HTLV-1 Env-dependent syncytium formation. Moreover, overexpression of NRP1 increases both HTLV-1 and HTLV-2 Env-dependent infection, whereas down-regulation of endogenous NRP1 has the opposite effect. Finally, overexpressed GLUT1, NRP1, and Env form ternary complexes in transfected cells, and endogenous NRP1 and GLUT1 colocalize in membrane junctions formed between uninfected and HTLV-1-infected T cells. These data show that NRP1 is involved in HTLV-1 and HTLV-2 entry, suggesting that the HTLV receptor has a multicomponent nature.

Animals↗

Fas ligand-mediated lethal hepatitis after rapid lysis of a localized natural killer cell lymphoma.

Natural killer (NK) cell malignancies have been associated with neutropenia and disturbances of liver function tests, thought to be related to high levels of soluble Fas ligand (FasL) in the circulation. We report a case of fulminant hepatitis occurring 3 weeks after the initiation of salvage therapy by arginine butyrate and ganciclovir for refractory Epstein-Barr virus-positive NK cell lymphoma. Pathologic examination revealed disappearance of the NK tumor and massive liver injury caused by apoptosis of virtually all hepatocytes. Immunohistochemistry revealed an intense staining for FasL. To our knowledge, this is the first description of the occurrence of FasL-mediated lethal hepatitis after lysis of a NK cell lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗

A double-blind low dose-finding phase II study of granulocyte colony-stimulating factor combined with chemotherapy for stem cell mobilization in patients with non-Hodgkin's lymphoma.

The aim of the study was to define the minimal effective dose (MED) of granulocyte colony-stimulating factor (G-CSF) among five daily doses following chemotherapy for peripheral blood stem cell (PBSC) collection. Twenty-five patients were included in this double-blind dose-finding phase II study conducted according to a two-stage Bayesian design. The estimated probabilities of success for PBSC collection for the G-CSF doses of 50, 75, 100, 125 and 150 microg/m2/day were 84%, 87.7%, 91%, 93.9 and 96.4%, respectively. Low G-CSF doses may be used with a similar probability of success as conventional doses and could allow significant savings.

Adult↗

Antineutrophil cytoplasmic antibody-associated neutropenia.

BACKGROUND: Antineutrophil cytoplasmic antibodies (ANCA) can be associated with various disorders. However, their association with neutropenia has never been reported. METHODS: Nine patients with chronic unexplained neutropenia and ANCA were studied. Clinical charts were extensively analyzed and all patients underwent hematological and immunological investigations. RESULTS: All patients (6 women and 3 men) were Caucasian and had a mean age of 49 years (range 16-67 years). All presented with a neutropenia below 1.5x10(9)/L for more than 6 months. The neutropenia was <0.5x10(9)/L in six cases and moderate in three. There was no evidence of toxic- or drug-related neutropenia or of a hematological malignancy. Autoimmune anemia and/or thrombocytopenia were present in five patients. ANCA, with various specificities, were present in all patients. ANCA were associated with various other autoantibodies in eight patients, including antisurface-neutrophil antibodies in three cases. Four of the six patients with severe neutropenia experienced infections. Five patients were treated with hematopoietic growth factors, steroids, intravenous immunoglobulins, splenectomy, methotrexate and/or cyclophosphamide, allowing the neutrophil count to be restored transiently or permanently. CONCLUSIONS: A subset of patients with neutropenia of possible autoimmune origin may develop ANCA. Their detection would provide strong evidence of an autoimmune mechanism. Neutropenia should be added to the list of ANCA-associated diseases.

Journal Article↗

New therapeutic approaches for adult T-cell leukaemia.

Adult T-cell leukaemia or lymphoma is an aggressive malignant disease of mature activated T cells caused by human T-cell lymphotropic virus type I. Patients with this disease have a very poor outlook because of intrinsic chemoresistance and severe immunosuppression. In acute adult T-cell leukaemia, clinical trials in Japan show that although non-targeted combinations of chemotherapy improve response, they do not have a significant effect on complete remission and survival. Antiretroviral therapy with combination zidovudine and interferon alfa, which induces a high rate of complete remission and lengthens survival, should be the first treatment option in acute adult T-cell leukaemia. Patients with adult T-cell lymphoma might benefit from initial aggressive chemotherapy followed by antiretroviral therapy. To prevent relapse in all patients allogeneic bone-marrow transplantation when feasible, or additional targeted therapy, should be mandatory. Based on current pathophysiology, we discuss promising new drugs such as arsenic trioxide, proteasome inhibitors, retinoids, and angiogenesis inhibitors, as well as cellular immunotherapy.

Anti-Retroviral Agents↗

Relationship between levels of indinavir in hair and virologic response to highly active antiretroviral therapy.

BACKGROUND: Suboptimal levels of antiretroviral drugs result in virologic failure in HIV-infected patients treated with highly active antiretroviral therapy (HAART). OBJECTIVE: To assess the relationship between levels of indinavir in hair and virologic outcome. DESIGN: Cross-sectional study. SETTING: 7 AIDS clinics in France. PATIENTS: 89 HIV-infected patients who received HAART that included indinavir. MEASUREMENTS: Patients were classified as responders or nonresponders on the basis of viremia at the time of hair collection. In nonresponders, levels of indinavir in hair and resistance mutations in the protease gene were assessed at baseline and at the time of indinavir measurement. RESULTS: Mean indinavir levels (+/-SD) were significantly higher in the 65 responders than in the 24 nonresponders (24.4 +/- 16 microg/g vs. 12.9 +/- 8.6 microg/g) (P < 0.001). Nonresponders with intermediate levels of indinavir in hair had more mutations in the protease gene than did nonresponders with low levels of indinavir in hair. CONCLUSION: Indinavir levels in hair are associated with virologic outcome in patients receiving HAART.

Absorption↗

Control of a relapse and induction of long-term remission of Wegener's granulomatosis by cyclosporine.

We report a case of severe Wegener's granulomatosis that caused end-stage renal failure and recurrent flares of sinusitis and pulmonary manifestations. To avoid the cumulative toxicity of iterative treatments with cyclophosphamide pulses and glucocorticoids, treatment with cyclosporine as a single agent was instituted in the early phase of the third relapse, before any pulmonary involvement. Cyclosporine enabled rapid control of the disease and induced a complete remission of more than 30 months.

Adult↗