Intracellular immunoglobulin production in vitro by lymphocytes from patients with hypogammaglobulinaemia and their effect on normal lymphocytes.

The ability of peripheral blood lymphocytes from twenty-two patients with late onset (acquired or common variable) hypogammaglobulinaemia to produce immunoglobulin was assessed by the immunofluorescent detection of intracytoplasmic immunoglobulin (Ic-Ig) in cultures stimulated with pokeweed mitogen (PWM). Intracellular immunoglobulin was found in 4-9-26% of cultured cells from eighteen out of nineteen controls. In contrast nineteen out of twenty-two patients with hypogammaglobulinaemia showed values less than 1% and in ten no Ic-Ig was detected. Two of the remaining three patients showed normal values. Lymphocytes from eleven patients showing less than 1% positive cells were selected for mixture experiments. Lymphocytes from five of the eleven patients strongly depressed immunoglobulin synthesis by normal lymphocytes when mixed together in the presence of PWM. However, lymphocytes from these individual patients did not depress immunoglobulin production in all normal controls.