Increased chromosomal radiosensitivity in patients undergoing radioimmunoglobulin therapy.

Lymphocytes from individual patients undergoing radiolabeled immunoglobulin therapy have been examined both for chromosome aberrations expressed immediately upon explant, or for chromosome aberrations induced by a subsequent challenge of gamma-rays after PHA-stimulated proliferation. Despite interpatient variation, there is strong correlation between levels of chromosome aberrations observed in the initial mitosis after mitogenic stimulation and levels induced by a challenge dose of radiation in replicate cultures after several cell cycles of growth. These data indicated that even after proliferation, human lymphocytes retain a memory of in vivo exposure to ionizing radiation that can be observed by challenge with a clastogenic agent. This persistent hypersensitivity occurs at high frequency, suggesting that it may be related to initial steps in multistage carcinogenesis.