Immunomodulation induced by immunoglobulins. I. Action of placental immunoglobulin on in vitro spontaneous synthesis of IgE in man.

The IgE contents of various therapeutic immunoglobulin (Ig) preparations of placental or plasmatic origin were measured. Their effects on spontaneous IgE synthesis by lymphocytes from healthy and atopic subjects were also studied. Whatever their origin, Igs contained IgE in varying amounts, depending on the batch. Only Igs of placental origin inhibited spontaneous IgE synthesis; this effect appeared linked to IgE content.