Volume regulation in lymphoid leukemia cells and assignment of cell lineage

Normal T lymphocytes readjust their volume after swelling in hypotonic medium, whereas B lymphocytes remain swollen. The difference between the two cell types appears to lie in the inability of B cells to increase their permeability to potassium in response to swelling. We have studied mononuclear cells from the bone marrow of 65 patients with lymphocytic leukemia, to determine whether the response to a hypotonic environment could be used to assign cell lineage. In contrast to leukemic cells of B-cell lineage (as in B-cell acute or chronic lymphocytic leukemia and non-T-cell, non-B-cell acute lymphocytic leukemia), T-cell-leukemia cells responded within five minutes to hypotonic swelling with an increase in potassium permeability and restoration toward isotonic volume. We conclude that the response to hypotonic shock may distinguish leukemic cells of T-cell origin from those derived from B-cell precursors and provides a simple, rapid, and reliable means for assigning cell lineage to lymphoid leukemia cells.