Expression and function of L-selectin molecules (LECAM-1) in B-cell chronic lymphocytic leukemia

Department of Pathology, University Medical School of Pecs, Hungary.

BACKGROUND. The notion that adhesion molecules play a crucial role in lymphoma/leukemia dissemination is widely accepted. Individual cases of B-cell chronic lymphocytic leukemia (B-CLL) show well-defined variables in the extent and pattern of peripheral blood and nodal involvement. The L-selectin adhesion molecule (TQ1/Leu-8, LAM series and LECAM-1) initiates the attachment of lymphocytes to the high endothelial venules (HEVs), and as a consequence the entrance of lymphocytes from the blood into the peripheral lymph node (recirculation which may be operative in lymphoma/leukemia dissemination as well). MATERIALS AND METHODS. The constitutional expression of L-selectin molecules (LECAM-1) on peripheral blood mononuclear cells (PBMCs) from B-CLL (16 cases) was examined and correlated with receptor function in an HEV-binding assay and in a ligand immobilization test. RESULTS AND CONCLUSIONS. A correlation was found between constitutional expression and function of the L-selectins, namely the higher the number of cells expressing L-selectin molecules at a measurable level on the cell surface, the greater the number of cells showing attachment in the tests. It is suggested that many aspects of the biological and clinical heterogeneity of B-CLL will be explained by revealing the exact adhesion profile and function in different subtypes of the disease.