Effect of radiation dose on patients' immune response

This paper studies the relations between dose delivered and changes in T-cell subsets as an expression of the effect of radiation therapy on patients' immune response. One hundred twenty-eight patients were studied before and 6 weeks after irradiation. Blood samples were analyzed by flow cytometry. A dose effect was noted wherein the OKT4 helper/OKT8 suppressor cell ratio was reduced by more than 10% in 79% of patients receiving a dose greater than 6,000 cGy as compared with 54% of patients given a lower dose (P = .01). Several variables, including sex, age, tumor site, and cancer burden, were analyzed. Male subjects showed a greater reduction of OKT4 helper cells at doses greater than 6,000 cGy-73%, versus 47% in female subjects (P = .05)