الفهرس 
Acute Lymphoblastic LeukemiaOnly 14 pages are availabe for public view
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Abstract
Acute lymphoblastic leukemia (ALL) is a heterogeneous group of lymphoid disorders that result from a monoclonal proliferation and expansion of immature lymphoid cells in bone marrow, blood, and other organs. A better understanding of the biology of ALL has led to change in the pathologic classification of the disease, the emergence of new therapies, and the institution of risk adapted therapies. The adhesion molecule CD44 is a cell surface transmembrane glycoprotein encoded by single gene, involved in lymphocyte activation, recirculation and homing, adhesion of extracellular matrix, angiogenesis, cell proliferation, cell differentiation and cell migration, as a receptor for hyaluronic acid. All these biological properties are essential to the physiological activities of normal cells, but they are also associated with the pathologic activities of tumor cells. Elevated CD44 expression was correlated with poor prognosis in many malignancies, and though, scholars pay more attention to the association of CD44 with hematological malignancies. CD27 homodimer molecule is normally expressed on mature thymocytes and peripheral blood T cells, this molecule is induced on normal B lymphocyte after antigenic challenge and has been considered to be a general marker of memory B cell. CD27 plays an important role in lymphoid differentiation and apoptosis and is involved in B cell maturation. In ALL patients increased expression of CD27 is a sign for good prognosis. There are many prognostic factors as age, sex, white blood cell count, the presence of mediastinal mass and central nervous system involvement at diagnosis. Assessment of these factors is mandatory for therapy assignment. The present study aimed to study the role of CD44 and CD27 in patients with acute lymphoblastic leukemia and trying to evaluate its clinical significance. CD27 and CD44 expression was determined in 60 newly diagnosed patients with ALL by flow cytometry and their relation to established prognostic factors and response to therapy was investigated. In addition 30 apparently healthy children matched in age were included as a control group. Patients were followed after chemotherapy for a period ranged from 6-12 months. Patients and controls were subjected to the following: 1- History taking and careful clinical examination. 2- Routine laboratory investigations: Complete blood picture. Bone marrow examination, cytochemistry and immunophenotyping (for patients). ESR and LDH levels. 3- Special laboratory investigations: Estimation of level of both CD44 and CD27 expression in peripheral blood (for patients and control) or in bone marrow samples (for patients) by flow cytometry. The 60 studied ALL patients were subdivided into four groups according to CD44 and CD27 expression: group (I): CD44 single positive group, group (II): CD27 single positive group, group (III): CD44/CD27 double positive group, and group (IV): CD44/CD27 double negative group.