Variant type of sialyl Lewis X antigen expressed on adult T cell leukemia cells is associated with skin involvement.

Expression of a variant type of sialyl Le(x) antigen defined by 2F3 monoclonal antibody on leukemia cells was studied in 15 adult T cell leukemia (ATL) patients. The expression of 2F3-defined sialyl Le(x) antigen on CD4+CD45+ cells, which is an ATL cell-rich population, was higher in patients with skin involvement (50.1 +/- 23.1% were positive) than in patients without skin involvement (18.1 +/- 12.5%) (P < 0.01). The other surface markers including classical sialyl Le(x) antigen defined by SNH3 or FH6 and LFA-1, VLA-4, CD4, CD25, ICAM-1, Leu8, and HLA-DR did not show a significant difference regardless of skin involvement. In the skin lesion of four patients that we could examine, infiltrating leukemia cells strongly expressed 2F3-defined sialyl Le(x) antigen. In one patient, we could also examine the expression of classical sialyl Le(x) antigen defined by SNH-3 and CSLEX-1, but this was almost negligible. Both skin and lymph node biopsy specimens were examined in two patients. Leukemia cells in the skin strongly expressed 2F3-defined sialyl Le(x) antigen, while its expression was almost negligible on the leukemia cells in the lymph node. These findings suggest that the expression of 2F3-defined sialyl Le(x) antigen on ATL cells is associated with skin involvement of ATL.