[A dynamic study on titer of EB virus VCA/IgA and EA/IgA in nasopharygeal carcinoma patients].

OBJECTIVE: To analyze the change of EB virus VCA/IgA and EA/IgA titer during the development of nasopharyngeal carcinoma (NPC), and the role in screening for NPC. METHODS: VCA/IgA and EA/IgA were monitored in a period of 12 years by immunoenzymatic titration from the sera of 54 NPC patients after primary serological screening. RESULTS: VCA/IgA and EA/IgA titer had shown gradual increment 1 - 7 years before NPC was pathologically diagnosed. The mean titer of VCA/IgA was 1:21.04, 7 - 4 years before diagnosis. VCA/IgA titer ascended quickly within 3 years before diagnosis. The geometric mean titer (GMT) of VCA/IgA and EA/IgA were 1:76.86 and 1:6.49 when NPC was diagnosed, which descended quickly after radiotherapy and, in 4 years, approached the average titer of VCA/IgA positive population. CONCLUSION: VCA/IgA titer rises uninterruptedly 3 years before NPC is diagnosed pathologically in most patients but their EA/IgA titer rises slowly. The detection of VCA/IgA titer can be used to find early NPC, whereas EA/IgA can not. The pre-clinical phase of NPC is 3 years according to this dynamic study.

[Clinical analysis and long-term follow up study of asymptomatic nasopharyngeal carcinoma patients].

OBJECTIVE: To observe the character of Epstein-Barr(EB) virus serology, fibroscopy appearance and prognosis of asymptomatic nasopharyngeal carcinoma(NPC). METHODS: Viral capsid antigen's IgA (VCA/IgA) of EB virus and early antigen's IgA(EA/IgA) of EB virus were detected by immunoenzymatic method. The clinical examination was carried out, including indirect mirror examination and fibroscopy of the nasopharynx and multiple biopsies. All patients of NPC were followed up to the end of 1999. RESULTS: 1. The geometric mean titer of VCA/IgA and EA/IgA are 1:100.79 and 1:10.76 respectively when asymptomatic NPC was diagnosed. There were no significant difference between VCA/IgA and EA/IgA antibody titres of asymptomatic patients and symptomatic cases (P > 0.05). The survival rates in these asymptomatic cases were higher than symptomatic patients (P < 0.05). 2. There was no correlation with the VCA/IgA or EA/IgA titer and the prognosis (P > 0.05) and the cervical lymph node metastasis (P > 0.05) when NPC was diagnosed. CONCLUSION: This is helpful to detect asymptomatic NPCs by EB serological screening periodically and nasopharyngeal fibroscopy and multiple biopsies.