T lymphocyte subpopulations in blood following radiation therapy for breast cancer

Abstract T helper and T suppressor lymphocyte subpopulations were examined before and after postoperative adjuvant radiation therapy for breast cancer. Absolute numbers of all T cell subsets were reduced by 70–80% . The proportion of IgG-Fc receptor-bearing T cells (T g cells) was significantly reduced and that of IgM-Fc receptor-bearing T cells (T m cells) significantly increased at completion of local radiation therapy with 45 Gy (4500 rad) . Proportions of T suppressor (T s ) and T helper (T h ) cells determined by monoclonal antibodies were not changed by radiation therapy. The overlapping between T g and T s subpopulations was 20–30% as examined by double labelling.