Altered membrane-associated functions in chronic lymphocytic leukemia cells

Abstract

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.