*M. Lima, * M.L. Queirós, *M.A. Teixeira, *C. Gonçalves, *J.Coutinho, *L. Pinho, *P. Ribeiro, ** A.L. Canelhas, **S. David, *B. Justiça.
*Service of Clinical Hematology and
Introduction : The bcl-2 gene is a unique protooncogene that blocks apoptosis and is product (p26 protein) is localized on the inner mitochondrial membrane. The over expression of the bcl-2 protein was first described in follicular lymphomas bearing the t(14;18) chromossomal translocation, which juxtaposes the bcl-2 gene with the Ig heavy chain locus. Further studies revealed that the bcl-2 (p26) is also expressed in other B and T-cell leukemias/lymphomas, indicating that mechanisms other than t(14;18) may disregulate bcl-2 expression.
Material : We have studied the bcl-2 (p26) protein on B and T lymphocytes obtained from the peripheral blood and / or bone marrow aspirate of patients with various B and T lymphoproliferative disorders, including chronic lymphocytic leukemias and low-grade non-Hodgkin lymphomas. The results were compared with those obtained in normal B and T lymphocytes.
Methods : Cells were double stained for surface CD19 and mitocondrial bcl-2(p26). The analysis of the bcl-2(p26) expression on B and T cells was performed by flow cytometry.
Results : We found that bcl-2(p26) is overexpressed in most, but not all, chronic lymphoproliferative disorders, comparatively to normal T and B lymphocytes.
Comments : The different levels of bcl- 2(p26) expression observed in chronic lymphoproliferative disorders may account for the different biological and clinical behaviour of the disease. Further studies are necessary in order to clarify the significance of the bcl2- expression.