Application of an immunoenzymatic method and an immunoautoradiographic method for a mass survey of nasopharyngeal carcinoma.

The frequency of IgA antibody to virus capsid antigen (VCA) of EB virus was tested by an immunoenzymatic method among adults in a mass serological screening of the general population of 6 communes in South China, as a guide toward early detection of nasopharyngeal carcinoma. Sera from 56 patients already recognized as having nasopharyngeal carcinoma (NPC) also were tested. The screening was conducted with sera from 56,584 persons age 30 years and older in Zangwu County in the Guangsi Zhuang Autonomous Region. IgA antibody to VCA was found in 96% of the NPC patients tested; the geometric mean antibody titer for this group was 1:41. The antibody also was detected in 117 of the persons surveyed in the mass screening, and among these, the geometric mean antibody titer was 1:21. 20 of the antibody-positive persons were diagnosed by clinical and pathological examination as having NPC. 18 of these cases were diagnosed soon after the initial tests in June-September, 1978, and an additional 2 were diagnosed only after follow-up examinations 10 months after the first blood sample was taken. All of the persons who are in the antibody-positive group but exhibit no detectable tumors are to be reexamined periodically.