ANTIBODY AGAINST THE EPSTEIN-BARR-VIRUS BHRF1 PROTEIN, A HOMOLOG OF BCL-2, IN PATIENTS WITH NASOPHARYNGEAL CARCINOMA

The Epstein-Barr virus (EBV) open reading frame BHRF1, a homologue of the oncogene bcl-2, was cloned from a patient with nasopharyngeal carc inoma (NPC) and overexpressed in Escherichia coli. The resulting recom binant BHRF1 fusion protein, with an apparent molecular weight of 35 K D, was used as antigen in an immunoblotting assay for IgG antibody in human sera. Anti-BHRF1 antibody was detected in 57 (61.3%) of 93 patie nts with NPC, 5 (5.7%) of 87 patients with nonmalignant diseases of th e nasopharynx, and in 1 (1.3%) of 78 healthy blood donors. The positiv ity rate in these nonmalignant patients was 4.4 times that of the norm al controls. Negative results were observed in four patients with infe ctious mononucleosis and patients with other cancers, including 4 with esophageal cancer, 11 with lung cancer, 10 with lymphoma, 13 with gas tric carcinoma, 10 with cervical carcinoma, and 10 with other head and neck cancers. Antibody neutralizing EBV DNase and IgA antibody to vir al capsid antigen (VCA) were assayed in parallel. The results showed t hat 7.5% of the NPC patients were negative for anti-DNase and anti-VCA antibodies and EBV infection could be detected by the anti-BHRF1 anti body atone. The demonstration of anti-BHRF1 antibody in most NPC sera strongly supports the hypothesis that the EBV BHRF1 protein is express ed in most NPC patients and its specific antibody can be a useful mark er for the diagnosis of NPC. J. Med. Virol. 56:779-785, 1998. (C) 1998 Wiley-Liss, Inc.