Chimeric twins. T.S. and M.R. reexamined.

A pair of chimeric twins, T.S. (male) and M.R. (female), were examined. The amounts of 'foreign' blood cells in each twin found on three occasions were compared. The percentages of M.R. cells found in the blood of T.S. in 1977 and in 1982 were similar and about 1/5 of that found in 1970. The amount of T.S.-blood cells found in M.R. was declining slowly from about 31% in 1970 to about 25% in 1982.