[Post-partum survival of fetal lymphocytes in the maternal blood].

Cells of fetal origin have been searched for in the peripheral blood of mothers following delivery of a boy, using mepacrine fluorescence of the Y chromosome. In a series of 62 women such cells have been found for approximately two years in more than half of cases. Their number decreases thereafter but in some instances Y chromosome-bearing cells have been observed 5 years after delivery.