BCL-2 BUT NOT ITS EPSTEIN-BARR VIRUS-ENCODED HOMOLOG, BHRF1, IS COMMONLY EXPRESSED IN POSTTRANSPLANTATION LYMPHOPROLIFERATIVE DISORDER

Posttransplantation lymphoproliferative disease (PTLD) is virtually al ways associated with Epstein-Barr virus (EBV) infection. BCL-2 and oth er proteins that confer resistance to apoptosis have been implicated i n the pathogenesis of a variety of malignancies including lymphomas. O ne EBV protein, BHRF1, is a homologue of BCL-5, whereas another, the l atency membrane protein 1 (LMP-1), upregulates BCL-2 expression in vit ro. In the present study, we used immunohistochemistry to study the ex pression of these viral and cellular proteins as well as a variety of other EBV-encoded proteins in PTLD. BHRF1 was not detected in any PTLD specimen, whereas BCL-5 was shown in 12 of 17 lesions examined. With one exception, all LMP1-positive cases also expressed BCL-2 and the ab sence of LMP1 was always associated with a lack of BCL-2 expression. T he results do not support a role for the EBV homologue of BCL-2 in PTL D, but they do support a role for viral induction of BCL-2 expression. (C) 1996 by The American Society of Hematology.