The FcɛR2/CD23 antigen: A hallmark of chronic lymphocytic leukemia B cells

Summary The effect of different stimuli on the expression of the low-affinity receptor for the Fc fragment of IgE (FcɛR2/CD23) on peripheral blood B cells from patients with chronic lymphocytic leukemia (CLL) was investigated. CLL B cells cultured for 3 days in medium alone showed a progressive decrease of the FcɛR2/CD23 expression, while the addition to the cell cultures of IgE or interleukin-4 had a slackening effect on the decrease of the FcɛR2/CD23. In contrast, in the presence of interferon-γ the proportion of FcɛR2/CD23⁺ cells was more rapidly reduced compared to CLL B cells cultured in medium alone. Stimulation of CLL B cells withStaphylococcus aureus Cowan I (SAC) bacteria, which are able to enhance the expression of FcɛR2/CD23 on normal B cells, induced a rapid loss of the FcɛR2/CD23 from CLL B cells.