ALTERED MEMBRANE-ASSOCIATED FUNCTIONS IN CHRONIC LYMPHOCYTIC-LEUKEMIA CELLS

Peripheral blood lymphocytes consisting mainly of neoplastic B cells from patients with chronic lymphocytic leukemia (CLL cells) showed a markedly reduced response to the human B‐cell mitogens anti‐β2 microglobulin, Sepharose‐bound protein A and Sepharose‐bound anti‐human immunoglobulin (anti F(ab′)2) in all of nine patients studied. On the other hand, CLL cells from three out of eight patients tested responded well to the calcium ionophore A23187. Sepharose‐bound protein A and anti‐β2 microglobulin also failed to induce increased uptake of 86Rubidium (potassium analogue) in CLL cells as compared to B‐cell‐enriched preparations of normal peripheral blood lymphocytes. The capacity of CLL cells to cap various surface markers including β2 microglobulin was reduced. On the other hand, surface concentrations of β2 microglobulin were not reduced as measured by fluorescein‐labelled anti‐β2‐microglobulin in singlecell cytofluorometry. It is concluded that various membrane‐associated events elicited by ligandreceptor interactions are altered or blocked in CLL cells. Copyright © 1978 Wiley‐Liss, Inc., A Wiley Company