Elimination of an abnormal cell line from blood lymphocytes during post-natal growth.

A cell line carrying an additional metacentric chromosome of unknown origin was present in PHA-stimulated blood lymphocytes from a newborn female. The child had no marked physical or developmental abnormality but was small. The abnormal cell line, present in 20 % of blood cells at birth, progressively decreased and was absent by 16 months. Loss of the cell line appeared to involve a process of elimination rather than a chance event.