Immunohistochemistry of Hodgkin and non-Hodgkin lymphomas with emphasis on the diagnostic significance of the BNH9 antibody reactivity with anaplastic large cell (CD30 positive) lymphomas

Abstract

Background: Morphologic and immunohistologic studies were performed on a series of 213 lymphoma cases, including CD30-positive anaplastic large cell (ALC) lymphomas (45 cases), other CD30-positive (18 cases) or CD30-negative (72 cases) non-Hodgkin lymphomas (NHL), cases of Hodgkin disease (HD) (73 cases), and an additional 5 cases exhibiting features of both CD30-positive ALC and Hodgkin lymphomas.

Methods: The aim was to assess differential expression by tumor cells of CD30/BerH2, epithelial membrane antigen (EMA), and other monoclonal antibodies, including BNH9, an epithelial and endothelial marker that has been found to be reactive with ALC lymphoma cells.

Results: A significantly greater proportion of cases of ALC lymphoma compared with HD exhibited positive results for CD45, EMA, CD45RO, and CD3 in CD30-positive atypical large cells, whereas Reed-Sternberg cells in HD most frequently coexpressed CD15 and CD30 antigens. ALC lymphoma cells reacted with BNH9 MoAb in 10 of the 42 (23.8%) assessable cases, whereas Reed-Sternberg cells reacted with this antibody in 5 of 73 (6.8%) HD cases. Only 3 of 90 (3.3%) NHL cases had positive results for BNH9; they were CD30-negative high-grade or low-grade lymphomas. It was noteworthy that 9 of 10 BNH9-positive ALC lymphomas also were EMA positive. Four of the five cases with morphologic features intermediate between those of HD and ALC lymphoma showed immunohistologic findings (positive results for CD30 and CD15, negative results for EMA, CD45, and BNH9) similar to those frequently observed in the HD cases; conversely, the remaining case showed a profile (positive results for CD30, CD45, and EMA, negative results for CD15) typically observed in ALC lymphomas.

Conclusions: This study suggests that the differential expression of CD45, EMA, and CD15 could be used in the distinction of ALC lymphomas and HD, whereas it seems that BNH9 antibody reactivity may be of diagnostic use only in that it reinforces the diagnostic value of EMA expression in the differentiation of these entities.