Existence of a differentiation blockage at the stage of a megakaryocyte precursor in the thrombocytopenia and absent radii (TAR) syndrome.

The thrombocytopenia and absent radii (TAR) syndrome is a rare disease associating bilateral radial agenesis and congenital thrombocytopenia. Here, we investigated in vitro megakaryocyte (MK) differentiation and expression of c-mpl in 6 patients. Using blood or marrow CD34(+) cells, the colony-forming unit (CFU)-MK number was markedly reduced. CD34(+) cells were also cultured in liquid medium in the presence of a combination of 3 cytokines (stem cell factor, interleukin-3, and interleukin-6) or megakaryocyte growth and development factor (PEG-rHuMGDF) with or without SCF. In the presence of PEG-rHuMGDF, the majority of mature megakaryocytes (CD41 high, CD42 high) underwent apoptosis. This phenomenon was also observed in cultures stimulated by three cytokines. However, this last combination of cytokines allowed a more complete terminal MK differentiation. Surprisingly, a homogeneous population of CD34(-)CD41(+)CD42(-) cells accumulated during the cultures. This population was unable to differentiate along the myeloid pathways. This result suggests that a fraction of MK cells is unable to differentiate in the TAR syndrome. We subsequently investigated whether this could be related to an abnormality in c-mpl. No mutation or rearrangement in the c-mpl gene was found by Southern blots or by sequencing of the c-mpl coding region and its promoter in any of the patients. Using Western blot analysis, a decreased level of Mpl was found in patient platelets. A decreased level of c-mpl messenger RNA in TAR platelets was also detected with a lower c-mpl-P to c-mpl-K ratio in comparison to adult platelets. Altogether, these results demonstrate that the thrombocytopenia of the TAR syndrome is associated with a dysmegakaryocytopoiesis characterized by cells blocked at an early stage of differentiation. (Blood. 2000;95:1633-1641)

Low dose T-cell lymphocyte infusion combined with marrow T-cell depletion as prophylaxis of acute graft vs host disease for HLA identical sibling bone marrow transplantation.

T-cell depletion (TCD) of the bone marrow graft remains the most effective method to prevent severe graft versus host disease after allogeneic bone marrow transplantation. Early studies of HLA-identical sibling transplants showed that although T-cell depletion decreased GVHD, T-cell depleted transplants had higher risks of graft failure and leukemia relapse, leukemia free survival (LFS) was not improved compared to non-T-cell depleted transplants. In order to avoid graft failure and increased risk of relapse associated with this approach, we initiated a pilot study of T-cell depletion of the marrow graft combined with reinfusion of a fixed quantity of CD2+ peripheral blood T-cells. Depletion technique consisted in negative purging using CD2 and CD7 monoclonal antibodies (MoAbs) followed by rabbit complement cytolysis. This approach was associated with an intensified conditioning regimen using total body irradiation, high-dose cytosine arabinoside and melphalan (TAM) for all but one patient. Twenty-one patients were included with a mean age of 40 years. Only one acute severe Graft Versus Host Disease (GVHD) was observed and all patients engrafted. At 63 months, probability of survival is 42.86% with a relapse risk of 19.89%, two patients died from B-cell lymphoproliferative disease, seven other died from the procedure partially because of the use of the TAM as pretransplant regimen. This approach is being pursued by a gene therapy trial using herpes-simplex - 1 thymidine kinase gene expressing peripheral donor T-cells.

[Listeriosis in patients with malignant hemopathy. 3 cases in the same hospital ward]. / Listériose chez des malades ayant une hémopathie maligne. Trois observations dans un même service.

During the listeriosis epidemic which occurred in France in the summer 1992, three patients with malignant haematopathies hospitalized in our service contracted the disease. Although the retrospective investigations were hindered by the variable incubation period and the impossibility of examining the foods eaten at the time of infection, there was a high probability that two of the patients had been infected by cooked ham and dairy products at home. The third patient was apparently infected in hospital with well-cooked food found to be contaminated. The hypothesis of coinfection has been raised.

Role of chemoresistance prior to autologous bone marrow transplantation for Hodgkin's disease.

In the present study, the response to last salvage chemotherapy was analysed in a series of 30 patients with poor prognosis Hodgkin's disease having received high dose chemotherapy followed by autologous bone marrow transplantation. The probability of survival was 43% at 152 months for the 21 chemosensitive patients as compared to 11% at 36 months for the 9 chemoresistent patients. Two toxic deaths occurred, both in the group of chemoresistant subjects, while the probability of absence of disease progression was 65% at 152 months in the 21 chemosensitive cases. According to these results, the response to the last conventional therapy before grafting is an important prognostic factor for survival and absence of disease progression after transplantation. Patients with chemoresistant Hodgkin's disease should benefit from new therapeutic approaches in the context of phase I or II clinical trials.

[Solitary plasmacytoma simulating pituitary adenoma]. / Plasmocytome solitaire simulant un adénome hypophysaire.

A case of solitary plasmocytoma of the sphenoid is reported, masquerading as pituitary adenoma. At the time of surgery, the patient had no findings of multiple myeloma. The tumor was removed by trans-sphenoidal route and radiotherapy delivered. The post-operative course was uneventful, and two years later, there is no sign of recurrency or extension of multiple myeloma.

Marrow transplantation from HLA non-identical family donors for the treatment of leukaemia: a pilot study of 15 patients using additional immunosuppression and T-cell depletion.

Fifteen patients with high-risk leukaemia were given T-cell depleted marrow transplants from HLA non-identical related donors. They were treated with a combination of total body irradiation (TBI), high-dose cytosine arabinoside (Ara-C) and high-dose melphalan in an attempt to prevent a host-versus-graft reaction. Antilymphocyte globulins were given prior to transplantation for additional immunosuppression to 13 patients and in-vivo monoclonal antibody anti-human LFA1 to two. Engraftment and chimaerism assessed by HLA typing were achieved in 14 patients. Seven developed acute graft-versus-host disease (two fatal), one failed to engraft. Six patients died in complete remission from cytomegalovirus (CMV) interstitial pneumonitis and three remain alive in complete remission 2, 3 and 13 months after transplant. We conclude that aggressive immunosuppression allows for sustained engraftment of T-cell depleted HLA non-identical marrow. The incidence and severity of GVHD are acceptable and CMV pneumonitis remains the major problem.