EXPRESSION OF HODGKINS-DISEASE ASSOCIATED ANTIGEN BLA.36 IN ANAPLASTIC LARGE-CELL LYMPHOMAS AND LYMPHOMATOID PAPULOSIS PRIMARILY OF T-CELL ORIGIN

Monoclonal antibody BLA.36 stains Reed-Sternberg (RS) cells and their mononuclear variants, as well as some benign and malignant cells of B-cell lineage, and retains its immunoreactivity in formalin- and B5-fixed tissue, The origin of the RS cell is controversial and the distinction between Hodgkin's disease (HD), anaplastic large cell lymphoma (ALCL), and lymphomatoid papulosis (LyP) (the latter two primarily T-cell in origin), can be difficult. The authors studied expression of BLA.36 in 22 cases of ALCL, 13 cases of LyP, and 15 cases of HD, Most atypical or malignant cells stained for BLA.36 in 10 of 22 cases of ALCL, 9 of 13 cases of LyP, and 9 of 15 cases of HD, Additional immunohistochemistry or gene rearrangement analysis indicated a T-cell origin for 8 of 10 BLA.36 positive ALCL, and 9 of 9 BLA.36 positive LyP cases, BLA.36 was expressed by T-cell lines derived from two ALCLs and one CD30+ cell line derived from LyP. The authors conclude that BLA.36 is not specific for lymphomas of B-cell origin and cannot he used to distinguish between HD, ALCL, and LyP with RS-like cells. These results further support a relationship between HD, ALCL, and LyP and suggest that RS cells are histogenetically related to both B- and T-lymphocytes.