Changes of blood T cell subsets following radiation therapy for breast cancer.

The changes of the size of various T cell subsets in the blood, as defined by monoclonal antibodies and Fc-receptors for IgG and IgM, were examined in 11 women after postoperative radiation therapy (45 Gy) for breast cancer. All subsets of T cells were significantly reduced at completion of irradiation. The most extensive depletion was noted in a subset with receptors for IgG, which may exert suppression. Approximately 1 year later this subset had recovered significantly in parallel with another subset, also rich in suppressor T cells, which was detected by monoclonal antibodies. On the contrary, T cell subsets rich in cells with helper activity did not exhibit any significant recovery.