Discontinuation of fucose therapy in LADII causes rapid loss of selectin ligands and rise of leukocyte counts

Leukocyte adhesion deficiency type II (LADII) is a rare inherited disorder of fucose metabolism. Patients with LADII lack fucosylated glycoconjugates, including the carbohydrate ligands of the selectins, leading to an immunod eficiency caused by the lack of selectin-mediated leukocyte-endothelial int eractions. A simple and effective therapy has recently been described for L ADII, based on the administration of oral fucose, Parallel to this treatmen t the lack of E- and P-selectin ligands on neutrophils was corrected, and h igh peripheral neutrophil counts were reduced to normal levels, This study reports that discontinuation of this therapy leads to the complete loss of E-selectin ligands within 3 days and of P-selectin ligands within 7 days. P eripheral neutrophil counts increased parallel to the decrease of selectin ligands, Selectin ligands reappeared promptly after resumption of the fucos e therapy, demonstrating a causal relationship between fucose treatment and selectin ligand expression and peripheral neutrophil counts. (C) 2001 by T he American Society of Hematology.