[Development of antigens ABH and Ii in children between 0 to 16 years old].

The ABH and I, i erythrocyte antigens of 926 children from birth to sixteen years were tested in a semi-quantitative assay in order to follow their development. Results show that total activities of A, B and H erythrocyte antigens are reached within 13 and 24 months, the main modifications being observed within the first three months of life. However, these activities depend on the agglutinins used in the test; notably the results with anti-H lectins from Ulex europaeus and Laburnum alpinum are not totally identical. The decrease of i reactivity and the increase of I reactivity are simultaneous, but at birth the I reactivity of cord red cells is widely distributed, while that of i is more homogeneous. The increase in H activity tested with Laburnum alpinum is directly related to the decrease of foetal hemoglobin in the children's red cells.