Langerhans' cell expression oftheselectin ligand, sialyl Lewisx

SUMMARYCellularadhesionmoleculesplay a central roleinleucocytemigrationthrough peripheral bloodandtissues. Acrucial stage inthese events is selectin-mediatedadhesioninvolvingE-selectinexpressed on activated endothelium interacting with a range of carbohydrate ligands expressed by specificsubpopulations of leucocytes. As such mechanisms may be relevant to bone marrow-deriveddendritic epidermal Langerhans'cell (LC)migration, expression ofthese carbohydrateligands was assessed immunocytochemically in wholeskin biopsies andin epidermal cell suspensions obtainedfrom adult humans. Double-labelling experiments revealed that sialyl Lewis x, recognized by themonoclonal antibody CSLEX1, was expressed on epidermal LC(n = 9). Furthermore, expression was enhanced at 24 hr following epicutaneous application of antigen and in the inflammatorydisorderpsoriasis (n = 10). E-selectin was concomitantly stronglyexpressed on dermalendotheliumin psoriasis and allergic contact dermatitis. Intradermal injection of the T-cell-derived cytokineinterferon-y(IFN-y)led