Evidence for the appearance of non-specific suppressor cells in the blood after local radiation therapy

Abstract

Radiation therapy for carcinoma of the breast may induce lymphopenia and a reduction of the purified protein derivative (PPD) tuberculin reactivity of the lymphocytes in vitro as measured on a cell-for-cell basis. In the present investigation we have examined whether the reduced PPD-reactivity after irradiation can be explained by the appearance of non-specific suppressor cells. The results confirm that the reactivity of non-purified lymphoid cell preparations decreases significantly after radiotherapy. This reduction was not correlated to the extent of radiation induced lymphopenia. In contrast, lymphoid cell preparations depleted of adherent cells do not exhibit any significant decrease, indicating that monocytes-macrophages may become non-specifically immunosuppressive after local radiotherapy.