INCREASED FREQUENCY OF CD4(-)8(-) T-CELLS BEARING T-CELL RECEPTOR ALPHA-BETA-CHAINS IN PERIPHERAL-BLOOD OF ATOMIC-BOMB SURVIVORS EXPOSED TOHIGH-DOSES

A rare T-cell subpopulation, CD4(-)8(-) alpha beta T cells, may be dif ferentiated through a pathway (or pathways) different from the pathway (s) of conventional CD4(+) or CD8(+) T cells. In the present study, th e frequencies of CD4(-)8(-) T cells in peripheral-blood (YP T cells in 409 atomic bomb survivors (160 estimated to have been exposed to 1.5 Gy or more and 249 controls) were determined to investigate late effec ts of radiation on the composition of human T-cell subpopulations. The frequency of CD4(-)8(-) alpha beta T-cell decreased significantly wit h the subject's age and was higher in females than males. A significan t increase in the frequency was found in the survivors exposed to more than 1.5 Gy, suggesting that the previous radiation exposure altered differentiation and development of T cells.