A spectrum of B-cell differentiation defects.

The nonparallel relationships between development of classes of B lymphocytes and of serum immunoglobulins during ontogeny and in some patients imply: 1) that B-cell differentiation is discontinuous and 2) that class-specific-controls for terminal B-lymphocyte differentiation exist. Three separate defects in B-cell differentiation in vivo have been identified using pokeweed mitogen stimulation of lymphocytes. B lymphocytes may fail to develop, may develop but lack the capacity to differentiate further, or may be normal in both respects. The latter result suggests involvement of other cell types in antibody deficiency.