Comparative Human Cellular Radiosensitivity: IV. The Increased Sensitivity of Human Neonatal Cord Blood Lymphocytes to γ-irradiation Compared with Lymphocytes from Children and Adults

Summary

We have compared the γ-irradiation survival of G₀ peripheral blood lymphocytes from 18 neonatal cord blood samples in a cloning assay with results from 21 controls (age range 1–65 years and consisting of 20 adults and one child). Using mean inactivation dose as the discriminating parameter, the cord blood cells showed a significantly greater radiosensitivity (mean inactivation dose for pooled data = 1·54 Gy) than the normal controls (mean inactivation dose for pooled data = 1·90 Gy, p < 0·001). These results confirm and extend earlier work suggesting that T-lymphocytes in newborn children are more radiosensitive than normal controls, and this may have implications for the radiation protection of the unborn child.