Sialosylated Lewis chi expression in CD30-positive anaplastic large-cell lymphomas

The expression of sialosylated Lewis chi (SLEX), a ligand for endothelial leukocyte adhesion molecule 1 in malignant lymphomas, was immunohistochemically examined, using the monoclonal antibody, CSLEX1, which specifically reacts with SLEX. It was expressed in 6 out of 64 non-Hodgkin's lymphomas, which consisted of 1 nasal large-cell lymphoma and 5 of 8 (62%) Ki-1-positive anaplastic large-cell lymphomas (ALCL). One nasal lymphoma positive for SLEX co-expressed a T cell marker, cluster of differentiation (CD) 5, and natural killer (NK) cell markers such as CD56 and CD16, indicating that SLEX+ nasal lymphoma cells are possibly malignant counterparts of SLEX+ NK cells. SLEX did not react with 30 B cell lymphomas or most Hodgkin's disease lymphomas, though it did with one lymphocyte predominance type. Although SLEX+ ALCL exhibit T cell markers in some cases, some ALCL expressing SLEX may represent histiocytic differentiation of the neoplastic cells. The lymphoma cells of ALCL were preferentially positive for SLEX, in contrast to Hodgkin's disease cells, and thus CSLEX1 in conjunction with CD30 and CD15 should be of use for analyzing and making differential diagnoses of routine paraffin-embedded sections of ALCL.