A serological mass survey was carried out in Wuzhou City of the Guangxi Autonomous Region, China. Sera were collected from 12,932 persons between the ages of 40 and 59. The positive rate of VCA/IgA antibody-positive person was 5.3%, but no EA/IgA antibody was found in sera from VCA/Iga-negative persons. Thirteen and nine nasopharyngeal carcinoma (NPC) patients were detected from the VCA/Iga and EA/IgA antibody-positive persons, respectively. With the present combination method the detection rate of NPC for 12,932 persons was 100.5/100,000 and for 680 VCA/IgA antibody-positive persons it was 1,900/100,000. Thus, the rate was twice and 37 times higher, respectively, than the annual incidence rate of NPC in persons of the same age group from 1975-1978 in Wuzhou City. Of 13 NPC patients, 9 were in stage I (70%) and 4 in stage II (30%). Therefore, it is possible to reduce the mortality rate of NPC in Wuzhou City by radiotherapy of NPC patients in the early stage of the disease. The present results further suggest that EB virus is closely associated with NPC.

An immunoautoradiographic method was used for the detection of EB virus IgA/EA antibody in sera from NPC patients and other control groups. Ninety-six percent of NPC patients had IgA/EA antibody with a high titer of GMT. The positive rates of IgA/EA antibody in patients with malignant tumours other than NPC and in normal individuals were only 4% and 0%, respectively. Eleven patients histologically diagnosed as having a chronic inflammation and who showed positive for IgA/EA antibody by immunoautoradiography were rebiopsied; six of them were discovered to have squamous cell carcinoma. Fourteen NPC patients had no IgA/EA antibody detected by immunofluorescence and immunoenzymatic testing, but 11 and six of them had IgA/VCA and IgA/EA antibodies detected by immunoautoradiography, respectively. These data indicate that the immunoautoradiographic method is more sensitive than either the immunofluorescence or immunoenzymatic test for the detection of IgA/EA antibody, and can be used for the detection of NPC in the early stages of development.