Suppression of B-cell differentiation by leukocytes from hypogammaglobulinemic patients

Leukocytes from patients with several forms of immunodeficiency characterized by apparently differing defects in B-lymphocyte maturation produced few or no plasmacytoid cells in vitro, and were capable of suppressing the generation of plasma cells in co-culture with cells of normal persons, in the presence of pokeweed mitogen. Such inhibition was commonly observed in cultures which included cells from patients with primary immunoglobulin deficiency, but was not seen to a significant degree in identical co-cultures of cells from normals. The suppression observed was not dependent upon mixed leukocyte culture reactivity. Both sheep erythrocyte-rosetting lymphocytes and adherent cells appeared to participate in these effects in some patients. In one patient with common variable immunodeficiency, but not in several others, removal of suppressing cells permitted the patient's remaining cells to differentiate into plasma cells in vitro. Because of the diverse syndromes in which suppression was observed, it is likely that, in at least some hypogammaglobulinemic patients, the suppression is secondary to the disease process rather than being the primary pathogenic mechanism.