VARIABLE EXPRESSION OF CD49D ANTIGEN IN B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA IS RELATED TO DISEASE STAGES

We have investigated the expression of the dual specific adhesion mole cule, VLA-4 (CD49d/CD29) on lymphocytes obtained from 62 patients with B-CLL and compared it with normal controls, patients with other hemat ological malignancies, and umbilical cord blood. The mean CD49d expres sion in patients with CLL was lower than the other group of leukemia a nd the CD19(+), CD5(+) cells of normal peripheral blood and umbilical cord blood (P < 0.001). The patients in RAI stage 0, I and II (early s tage) had even lower CD49d expression, whereas patients in RAI stage I II and IV (advanced stage) had relatively higher CD49d levels. In vitr o adhesion of lymphocytes to fibronectin, being the extracellular matr ix ligand of CD49d, was also investigated. Lymphocytes obtained from B -CLL were found to have lower adhesion to fibronectin than that from c ontrols (P < 0.03). Furthermore, CD49d(low) B-CLL cells had lower adhe sion to fibronectin, whereas CD49d(high) B-CLL cells showed normal adh esion ratios (P < 0.002). Further phenotypic analyses revealed the pre sence of myeloid markers (CD13 and CD33) in most of the advanced stage patients, although these were negative in early stage cases. Expressi ons of CD11a and sIgM were also low but CD11b was relatively higher in the early stages of the disease. On the basis of these results, we co ncluded that early stages of CLL are correlated with the expression of CD49d(low), CD11a(low), CD11b(high), CD13(-), CD33(-), sIgM(low) and also had lower fibronectin adhesion, whereas advanced stages of CLL ar e associated with CD(49)d(high), CD11a(high), CD11b(low), CD13(+), CD3 3(+), sIgM(high) and show normal fibronectin adhesion.