Nasopharyngeal carcinoma. IV. Evolution of complement‐fixing antibodies during the course of the disease

Sequential sera from 37 patients with nasopharyngeal carcinoma (NPC), with either controlled or uncontrolled tumours after radiotherapy, were studied for complement‐fixing (CF) antibodies against a soluble antigen extracted from the QIMR‐WIL lymphoblastoid line. When compared with results obtained previously with the same antigen on sequential Burkitt's lymphoma (BL) sera, the NPC sera exhibited (1) approximately ten‐fold higher CF antibody titres than the BL sera; (2) an overall stability of CF titres in the uncontrolled tumour groups contrasting with the situation in BL; (3) a two‐ to four‐fold decrease in CF titres in the controlled tumour groups; (4) similar CF titres in patients at stage I or IV of the disease. The above suggests an active and long‐standing EBV infection before and during the development of the clinical NPC disease.