ADHESION PROPERTIES OF ADULT T-CELL LEUKEMIA-CELLS

The interaction between neoplastic as well as normal T cells and vascu lar endothelial cells which is mediated by adhesion molecules play a k ey role in their trafficking, localization and infiltration. This brie f article reviews our studies on the expression of adhesion molecules on leukemic cells isolated from patients with adult T cell leukemia (A TL) and HTLV-I-infected T cell line cells and on their adhesion to hum an umbilical vein endothelial cells (HUVEC). Fresh ATL cells expressed lymphocyte function-associated antigen-1 (LFA-1), but the expression of very late antigen-4 (VLA4) and sialyl-Lewis(x) (SLex) was variable. Sialyl Lewis(a) (SLea) was not detected. Cell adhesion assays using H UVEC and adhesion-blocking antibodies revealed the consistent E-select in-mediated adhesion and variable VLA-4-mediated adhesion of ATL cells to HUVEC. The studies on HTLV-I-infected T cell lines confirmed the a bove data. These results, together with the detection of E-selectin ex pression on the endothelium of the skin infiltrated with ATL cells, in dicate that E-selectin-mediated adhesion is the major pathway for the adherence of ATL cells to endothelial cells. The possible role of such adhesion in the formation of skin lesions and other clinical manifest ations of ATL which result from the infiltration of leukemic cells is discussed.