Expression of VLA molecules on acute leukemia cells: relationship with disease characteristics

VLA molecules are involved in the adhesion of hematopoietic cells to the bone marrow stroma and play a role in the mediation of cellular interactions and migrations that are potentially important in the biology of acute leukemia (AL). We studied the expression of VLA-2 (CD49b), VLA-4 (CD49d), and VLA-5 (CD49e) by indirect immunofluorescence on leukemic cells from 67 patients with acute myelogenous leukemia (AML) and 40 patients with acute lymphoblastic leukemia (ALL). VLA-2, VLA-4, and VLA-5 were expressed, respectively, on 13 +/- 17%, 33 +/- 29%, and 36 +/- 30% of AML cells with 20, 54 and 61% positive cases and on 22 +/- 27%, 40 +/- 30%, and 39 +/- 29% of ALL cells with 29, 60, and 61% positive cases. Significant difference was neither noted between French-American-British (FAB) subtypes in AML or ALL nor between immunologic subtypes in ALL. There were highly significant correlations between the expression of the three beta 1-integrins tested in both AML and ALL. In AML, expression of both VLA-4 and VLA-5 was associated with that of CD14 (p = 0.003 and p = 0.01, respectively) and CD19 (p = 0.006 and p = 0.009, respectively). Expression of VLA-5 was correlated with that of CD15 (p = 0.004). Expression of VLA-4 was associated with both a high initial blast cell count (p = 0.01) and high percentage of bone marrow blast cell involvement (p = 0.003). In ALL, expression of VLA molecules was correlated neither with differentiation antigen nor with hematologic features. In AML, as in ALL, no significant correlation was noted between expression of VLA molecules and evolution of the disease.