EXPRESSION OF B7 (CD80) AND CD40 ANTIGENS AND THE CD40 LIGAND IN HODGKINS-DISEASE IS INDEPENDENT OF LATENT EPSTEIN-BARR-VIRUS INFECTION

Aim-To examine the expression of CD40 and B7 (CD80) antigens and the C D40 ligand in Hodgkin's disease. Methods-Antigen and ligand expression was studied in 17 cases of Hodgkin's disease using immunohistochemist ry. The study included 11 cases of Hodgkin's disease in which latent E pstein-Barr virus (EBV) infection could be demonstrated within tumour cells by in situ hybridisation for the EBV encoded early RNAs (EBERs). Results-In all cases, irrespective of EBV status, Reed-Sternberg cell s and their variants (HRS cells) showed strong expression of both B7 a nd CD40 antigens. CD40 ligand expression was not shown in HRS cells bu t was confined to a subset of small lymphocytes some of which were see n to be in intimate contact with HRS cells. Paraffin wax sections from a further 60 cases of Hodgkin's disease were examined for CD40 and EB ER expression alone. The CD40 antigen was identified in HRS cells in a ll of these cases irrespective of EBER expression. Conclusions-As CD40 and B7 expression are features of professional antigen presenting cel ls, these results provide further evidence that HRS cells may have ant igen presenting properties and that this may contribute to the charact eristic recruitment and activation of non-malignant lymphocytes which is a feature of Hodgkin's disease. The ability of HRS cells to activat e T-h cells may in turn contribute to their own survival through the i nduction of the gp39/CD40 pathway.