Long-term effects on the immune system following local radiation therapy for breast cancer. 4. Proliferative responses and induction of suppressor activity of the blood lymphocyte population.
The long-term effect of local irradiation for breast cancer on the blood lymphocyte population was examined in 149 women who had been disease-free for 5-6 and 10-11 years. The patients were included in a clinical trial aiming at determining the value of pre- and post-operative irradiation (45 Gy) compared to surgery only. It was observed that the relative mitogen responses of lymphocytes to phytohaemagglutinin (PHA) and Concanavalin (Con A) and in a mixed lymphocyte culture (MLC) were significantly lower in irradiated compared to unirradiated patients at least a decade after treatment. The prolonged reductions of mitogen responses after irradiation could partly be due to an increased proportion of lymphocytes which may express suppressor function since the Con A-inducible suppressor activity of lymphocytes was significantly higher in irradiated compared to unirradiated patients.
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000276:immunology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000528:radiation effects; D008214:Lymphocytes / Q000528:radiation effects; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000528:radiation effects*; D013997:Time Factors