BRAIN LYMPHOMAS OF IMMUNOCOMPETENT AND IMMUNOCOMPROMISED PATIENTS - STUDY OF THE ASSOCIATION WITH EPSTEIN-BARR-VIRUS

The Epstein-Barr virus (EBV) has been described in association with ly mphomas of the central nervous system. To test if the association betw een EBV and central nervous system lymphomas was limited to patients w ith immunosuppression or whether the association also held for patient s who were immunocompetent and to determine the true prevalence of any association, we studied 37 formalin-fixed, paraffin-embedded cases of central nervous system lymphomas occurring in immunocompromised and i mmunocompetent patients. EBV DNA-RNA in situ hybridization was perform ed using a 30-base biotinylated antisense oligonucleotide complementar y to the EBER1 gene of EBV. Immunohistochemistry was also performed, u sing a monoclonal antibody to the latent membrane protein of EBV. The most common histologic subtypes of lymphoma were high grade immunoblas tic (57%), diffuse large cell (22%), and small, noncleaved, non-Burkit t's (11%). Eighty-six percent of all tumors in our series were of B-ce ll lineage, as confirmed by CD20 expression, but only 37% of the prima ry tumors showed restricted CD20 expression. EBV RNA was identified in all or virtually all of the malignant lymphoid cells in 11 of the 37 cases (30%), including 10 primary brain lymphomas and one metastasis f rom systemic disease. Latent membrane protein expression was identifie d in 64% of the EBER1-positive cases. All 10 patients who had a histor y of immunosuppression had tumors that expressed EBV RNA. We confirm t he strong association of EBV with brain lymphomas occurring in immunoc ompromised patients, whether due to AIDS or to the immunosuppression a ssociated with organ transplantation. Our findings also demonstrate a low rate of EBV-positivity in immunocompetent patients.