Expression of Fas and Fas ligand in Hodgkin's disease

Fas and Fas ligand expression were investigated in twenty two cases of clas sical Hodgkin's disease (HD) by immunohistochemistry. While Reed-Sternberg (RS) cells in 7/22 (32%) cases expressed Fas ligand, reactive lymphoid cell s expressed Fas ligand in only 2 (9%) cases. In 20/22 (91%) cases, the RS c ells expressed Fas. A higher proportion of RS cells in the nodular sclerosi s subtype expressed Fas as compared to the mixed cellularity subtype. In 18 /22 (82%) cases, Fas expression was also noted in the reactive lymphoid cel ls. In eight cases, the reactive lymphoid cells were also analyzed by flow cytometry and a majority of them were CD4(+)CD45RO(+). Most of these activa ted T-cells expressed Fas but were negative for Fas Ligand. To investigate the co-expression of Fas and Fas Ligand in the RS cells, six cases were subjected to Fas and Fas ligand immunostaining on consecutive s ections. The co-expression was documented in the RS cells in four of six ca ses. These six cases with expression of both Fas and Fas ligand were invest igated for the incidence of apoptosis, There was no statistically significa nt relationship between expression of Fas on reactive cells, expression of Fast on RS cells and the proportion of apoptotic reactive cells. In all the se cases apoptosis was not observed in the RS cells. Thus Fas - FasL intera ctions may not lead to apoptosis of the RS cells.