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Biomedical subjects

F Porta

Publications and source records attributed to F Porta.

125 records · Page 7Linked to original sources
PubMedDate not supplied

Rhabdomyosarcoma with primary osteolytic lesions simulating non-Hodgkin's lymphoma.

We report the case of an 8-year-old child presenting with the pathological fracture of two vertebral bodies due to bone lytic lesions. Physical and instrumental examinations did not show any further evidence of disease. However, bone marrow aspirate showed an infiltrate of poorly differentiated cells. When the child was transferred to the Department of Pediatrics, lymphoblastic leukemia was suspected. Although the morphology of the bone marrow biopsy could have suggested a lymphoblastic lymphoma, further immunochemical and immunological studies together with the study of tissue surface antigens resulted in a diagnosis of embryonal rhabdomyosarcoma with an unusual presentation.

Antigens, Differentiation↗
PubMedDate not supplied

Functional depletion of T cells by vincristine and methylprednisolone as an in vitro model for the prevention of graft versus host disease.

BACKGROUND AND METHODS. The outcome of mismatched bone marrow transplantation is still severely hampered by graft versus host disease (GVHD) and graft rejection. Procedures for the recognition and selective elimination of T cells are still unsatisfactory due to the increased incidence of graft failure and late rejection. Lymphocyte proliferation and generation of cytotoxic T cells (CTL) in response to allogeneic cells are considered good in vitro correlates of GVHD and have been used in the present study to asses the capacity of two drugs (vincristine, VCR, and methylprednisolone, MP) to affect the T cells involved in these reactions. RESULTS AND CONCLUSION. Treatment in vitro with VCR and MP has been shown to inhibit the functional capacity of peripheral blood lymphocytes to proliferate (mean reduction 95.8%) and to generate CTL in response to haploidentical stimulator cells. Responsiveness to antigens and mitogens was affected to a minor extent (mean reduction 40% and 65.5%, respectively), and the method allowed recovery of hemopoietic precursors. The results suggest that treatment of donor bone marrow with VCR and MP is worth studying as a new approach to the prevention of GVHD in haploidentical bone marrow transplantation.

Bone Marrow Cells↗
PubMedDate not supplied

[Cellular and molecular therapy in severe combined immunodeficiencies].

Severe combined immunodeficiencies are usually fatal diseases unless affected children are admitted to protective isolation unit or unless the underlying immunological defect is treated by transplanting bone marrow from an healthy donor. The patients present, with early onset, life-threatening infections from fungal, viral or bacterial agents. Since only a minority of patients has an HLA-identical donor, recently other strategies have been devised including bone marrow transplantation from donors other than HLA-identical within the family or from HLA-non identical family members or from HLA-matched unrelated donors included in the International Bone Marrow Volunteers' Registry. In these cases, in order to realize this approach the "purging" of T-cells of the HLA-non identical donor bone marrow is necessary. Overall survival after HLA-identical BMT is 76%, when all BMT of the European multicenter analysis are considered, while in BMT from non-identical donors is 56%. Recently particular cases of SCID caused by enzyme deficiency, such as adenosine-deaminase (ADA), have been treated by molecular therapy with administration of polyethylene glycol (PEG) conjugated ADA: PEG protects from degradation and inhibits clearance of the enzyme. This approach, already realized in 15 children, allows reconstitution of cellular and humoral immunity, as demonstrated by one case treated by our group.

Adenosine Deaminase↗
PubMedDate not supplied

[Bone marrow transplantation in congenital defects of immunity].

BMT can cure several congenital immunological defects: if in these disease the engrafting is easier, the GVH reactions are more frequent and severe. The possibility to deplete from T lymphocyte the marrow before infusion, has overcame this difficulty. From 1968 183 BMT have been performed in Europe on patients with SCID (70 from HLA-identical donor, 113 from HLA-nonidentical donor). The survival after 2 years is 76% in the first group, and 56% in the second group (100 marrows have been T-depleted with different techniques). Strict isolation procedures before the transplant are very important to achieve good results. The possibility to treat different immunodeficiency With BMT are also discussed.

Bone Marrow Transplantation↗
PubMedDate not supplied

Factors leading to the appearance, after BMT, of cytotoxic antibodies against T, B and activated T lymphocytes: critical appraisal.

In order to investigate the role of lymphocytotoxic antibodies, acquired after allogeneic and autologus bone marrow transplantation, we studied 309 sera from 42 transplanted patients (16 adults and 26 children). We tried to correlate antibody elicitation towards T, B and activated T lymphocytes with the following parameters: genetic (recipient's and donor's sex, HLA profile), clinical (recipient's primary disease, GvHD, transplant outcome) and technical (bone marrow purging, auto-or allotransplant). There is evidence that anti-T and -B cytotoxic antibodies appear earlier than anti-activated T antibodies. Anti-HLA specific antibodies seem to be produced by the transfusional stimulus: they appear early after BMT and wane after the first year. Humoral responsiveness seems to be age related (adults are more responsive than children) and conditioned by GvHD (the level of cytotoxic antibodies decreases when GvHD is prevented by bone marrow purging). The level of cytotoxicity is significantly lower in the sera of autotransplanted patients compared with the allotransplanted ones. It appears that anti-activated T antibodies are produced by cell activation at different times in adults and children: in adults this occurs during GVHD and in children during the relapse of disease.

Adolescent↗
PubMedDate not supplied

Successful lectin-separated bone marrow transplantation in adenosine deaminase deficiency-related severe immunodeficiency.

Severe combined immunodeficiency disease (SCID) with adenosine deaminase (ADA) deficiency is a genetic autosomic recessive disorder with profound impairment of T-cell function, invariably complicated by fatal infections. The absence of ADA-enzyme and the accumulation of deoxy-ATP, with toxic effects on the T-lymphocytes is the common feature of this disease. As a consequence, lymphoid precursors failure to develop into mature T-cells, resulting in absolute lymphopenia and atrophy of the thymus. Bone marrow transplantation from an HLA-identical donor is considered the treatment of choice for this disease. We describe the case of a 1-month-old child with ADA deficiency SCID who underwent bone marrow transplantation (BMT) using paternal haploidentical, lectin-separated marrow, as a source of hemopoietic stem cells.

Adenosine Deaminase↗