Concanavalin A receptors on the surface membrane of lymphocytes from patients with acute leukemia

Peripheral blood mononuclear cells (PBM) isolated from 23 patients with acute lymphoblastic leukemia (ALL) and 24 with acute non-lymphoblastic leukemia (ANLL) were studied for binding and mobility of Concanavalin A (Con A) receptors, using fluorescent Con A (F-Con-A). The cap forming ability of PBM from all patients was 18.7 (+/- 9.3%) and 18.9 (+/- 9.9%) for ANLL patients at the time of diagnosis or during relapse. During clinical complete remission the cap forming ability of the PBM did not change significantly. No correlation was observed between the percentage of blasts present in the peripheral blood at the time of examination and the extent of cap formation, for both types of leukemia. The pattern of F-Con-A binding to PBM in ANLL patients was different compared to that seen in ALL. In ANLL, the fluorescent stain was concentrated in a round body on the cell ("button form") after binding to the membrane, while the rest of the cell showed almost no fluorescence. The present results indicate that PBM cells from patients with acute leukemia are characterized by a high degree of Con-A receptor mobility.