Anchorage and lymphocyte function: pattern of spreading distinguishes T- and B-cell chronic lymphocytic leukaemia.

T and B lymphocytes from normal individuals and patients with T and B chronic lymphocytic leukaemia (TCLL and BCLL) were induced to spread on a solid surface in the presence of Con A. The proportion of cell circumference exhibiting lamellar activity was considerably greater in T than in B cells. This difference also applied to T and B cells with a single leading lamellipodium. The different pattern of formation of active cell edges implied that the degree of polarity measured as the ratio between the largest and the shortest diameter (over the nucleus) was significantly greater in B than in T cells. This was also obvious when T and B cells, both with a single leading lamellipodium, were compared. The formation of active cell edges in T lymphocytes was generally accompanied by nuclear flattening, even in polar cells with a single leading lamellipodium. B cells, with the exception of one BCLL case, did not exhibit nuclear flattening. Thus, during the entire course of a contact-induced morphogenetic response, T- and B-cell leukaemias were easily distinguishable on the basis of the following criteria: (i) the proportion of the lymphocyte perimeter showing active cell edges, (ii) the degree of polarity and (iii) nuclear flattening.