Chromosomal aberrations and SCE in lymphocytes of children revaccinated against smallpox.

Chromosomal changes were analysed in the peripheral lymphocytes of 14 twelve-year-old children before and 3 months and 10 months after smallpox revaccination (group A), and in peripheral lymphocytes of 8 children of the same age before and 1.5 and 8 months after revaccination (group B). A significantly increased number of aberrant cells was found after 1.5 and 3 months. In the blood samples collected 8 and 10 months after revaccination there was a decrease in the number of aberrant cells which, however, did not reach the control level. Sister chromatid exchanges (SCE) were counted in 5 children 1.5 and 8 months after revaccination, and their numbers did not differ from controls.