Expression of sialyl 6-sulfo Le^x and related determinants on human peripheral leukocytes and in the skin. (A) Freshly isolated human peripheral leukocytes from a healthy donor were stained for sialyl 6-sulfo Le^x (G152), CLA (HECA-452) variant sialyl Le^x (2F3), and conventional sialyl Le^x (CXLEX-1). Gr indicates granulocytes; Mo, monocytes; Ly, lymphocytes. (B-C) Distribution of CLA- and sialyl 6-sulfo Le^x–positive lymphoid cells in the normal skin, as ascertained by immunohistochemistry. Note that HECA-452 (B) is reactive to keratinizing and parakeratinizing squamous epithelial cells (arrows) in addition to lymphoid cells, whereas sialyl 6-sulfo Le^x is expressed only in lymphoid cells (C).