Evidence for a malignant proliferation of IgE-class specific helper T cells in a patient with Sézary syndrome exhibiting massive hyperimmunoglobulinemia E.

Peripheral blood mononuclear cells (PBM) from a patient with Sézary syndrome exhibiting massive hyperimmunoglobulinemia E were examined in vitro. The patient's PBM and B cells (Bp) but not normal individuals' PBM and B cells (Bn) produced spontaneously large amounts of IgE. The addition of pokeweed mitogen (PWM) did not affect IgE production by both the patient's and normal individuals' PBM. The IgE production by PWM-stimulated Bp was depressed when cocultured with normal T cells but not depressed with the patient's T cells (Tp). When Tp were cocultured with Bn, significantly larger than expected quantities of IgE were produced. Ig assay of the same supernates showed that Tp had significantly less helper activities for IgG, IgA, and IgM production. Almost all Tp possessed the Leu3a and Leu3b antigens which are expressed on the helper/inducer T cell subset. These results indicate that the neoplastic cells in this patient originated from a subset of T cells programmed not for IgG, IgA, and IgM, but for IgE synthesis.