Disruption of Epstein-Barr virus (EBV) latency is mediated by

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Background. Epstein‐Barr virus BZLF‐1 replication activator (ZEBRA) is involved in the switch from viral latency to a productive cycle. Previous immunofluorescent study has shown that patients with nasopharyngeal carcinoma (NPC) have elevated immunoglobulin‐G (IgG) antibody titres against recombinant ZEBRA protein (ZEBRA/IgG). Methods. The prognostic role of ZEBRA/IgG was further investigated by enzyme‐linked immunosorbent assay (ELISA) in 110 NPC patients under long period of clinical follow‐up. Results. Ninety‐seven percent (85 of 88) of the patients with NPC had significantly higher ZEBRA/IgG titres (geometrical mean titre, i. e., GMT = 8397) than normal Chinese individuals (GMT = 233 and P < 0.0001). Based on Kaplan‐Meier analysis, the actuarial survival in patients with high ZEBRA/IgG titres (25%) after radiotherapy was significantly lower than that of those with low (76%; P = 0.0008) or intermediate titres (62%; P = 0.0036), although the titres taken before treatment did not bear such a relationship. Subdividing the patients into either individual UICC or Ho's stages, those with late‐stage disease (UICC Stage 4 and Ho's Stages 3 and 4) and with high ZEBRA/IgG titres also had poorer prognosis than those with disease of the same stages but who had low titres. Poor prognosis in those with high titres could be associated with a high risk of distant metastasis because consistent titre increase was found in the majority of patients who later developed distant metastasis either in the lung or liver. Only a minimal increase was found in patients with recurrence in the cervical lymph nodes. No consistent increase was observed, however, in patients whose disease was in remission or the majority of those with bone metastasis or local recurrence in the nasopharynx. Conclusion. The postradiotherapy ZEBRA/IgG titre could be a potentially useful marker for differentiating NPC patients with poor prognosis from those at high risk for the development of distant metastasis to the lung or liver.

Molecular investigations were done in a woman with a de novo balanced t(21q21q) discovered because of the birth of a trisomic 21 baby. Polymorphisms detected with probe ets-2 after Msp I digestion showed that both chromosomes 21 involved in the rearrangement were of maternal origin. The most likely hypothesis is that of a disomic 21 oocyte fertilized by a nullisomic 21 sperm.

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The Epstein-Barr virus (EBV) open reading frame (ORF) BCRF1, expressed in the late phase of the viral cycle, encodes a homologue of human intedeukin-10 (hlL-10). Unspliced, 3' co-terminal transcripts of 0-8 and 1.6kb from O-tetradecanoylphorbol 13-acetate (TPA)-treated B95-8 cells have been described but other results indicated the existence ofuncharacterized transcript(s) initiated upstream of the 1.6 kb BCRF1 mRNA. Here we describe two additional large transcripts of the BCRF10RF, a possibly spliced product of 3-5 kb and an unspliced product of 4.5 kb. The time course of the expression of BCRF1 transcripts and of the secreted protein from Akata cells were also determined.

The BamHI Z EBV replication activator (ZEBRA) protein is involved in the switch from latency to productive cycle of Epstein-Barr virus. A recombinant ZEBRA protein was synthesized and assessed in enzyme-linked immunosorbent assay (ELISA) for serum IgG response in nasopharyngeal carcinoma (NPC) patients. In 100 NPC serum samples that were positive for IgA to the EBV viral capsid antigen (VCA), 75% had IgG anti-ZEBRA antibodies. In contrast, only 3/83 (3.6%) serum samples from healthy donors and 2/50 (4%) from other cancers were positive for IgG to ZEBRA. Interestingly, in a selected group of 100 NPC sera negative for IgA to VCA, 25% contained IgG anti-ZEBRA antibodies. This suggests that the ELISA for IgG anti-ZEBRA may also identify earlier cases of NPC not detected by the conventional immunofluorescence test for IgA to VCA.