Leukaemic B cells from patients with chronic lymphocytic leukaemia suppress immunoglobulin production by lymphocytes from normal donors.

We observed that highly purified E-rosette-negative largely leukaemic B cells from 9 out of 15 patients with chronic lymphocytic leukaemia (CLL) significantly suppressed immunoglobulin production by mixtures of T4 and B cells from normal donors in the presence of pokeweed mitogen (PWM). This suppression by leukaemic B cells was concentration-dependent. Addition of equal numbers of B cells from normal donors to the mixtures of normal T4 and B cells increased, or had no effect on the production of IgM, IgA, and IgG. Treatment of purified largely leukaemic B cells from patients with CLL with either the anti-B1 or anti-Leu 1 monoclonal antibody plus complement abolished their ability to suppress immunoglobulin production. In contrast, treatment with either the anti-Leu 5 or the OKM1 monoclonal antibody plus complement had no effect on the suppression. These results suggest that leukaemic B cells from certain patients with CLL may exhibit, or can be induced to exhibit, immunosuppressive properties.