α-2-L-Fucosyltransferase Activity in Sera of Individuals with H-Deficient Red Cells and Normal H Antigen in Secretions

. α-2-L-Fucosyltransferase activity was found in the sera of 4 H-deficient secretor individuals (Hz). This activity represented about 5–10% of the activity present in the serum of normal H phenotypes.