Sera were collected a t intervals of 3 t o 8 months over a 4-t o 5-year period from more than 103 patients with nasopharyngeal carcinomas (NPC) and examined for their spectra and titers of antibodies t o Epstein-Barr virus (EBV)-related antigens. They were titrated for IgG, IgA and I g M antibodies t o EB viral capsid antigen (VCA), for IgG and IgA antibodies t o the D (diffuse) and R (restricted) components of the EBV-determined early antigen (EA) complex, and for antibodies t o the EBVassociated nuclear antigen (EBNA). In the as yet untreated patients the incidences and titers of most of the antibodies increased with the stage of the disease; i.e., essentially with the total tumor burden. Such increases were observed in individual patients whose disease ultimately progressed t o death, a t times well i n advance of the recognition of relapses o r metastases. Increases were not noted o r were only minor and delayed i n some fatal cases if the tumor extended t o the cranial cavity in the absence of significant involvement of cervical lymph nodes. I n contrast, patients who responded well t o therapy and remained clinically free of disease during the 4-o r 5-year observation period after, a t most, early minor relapses, showed gradual, steady declines in the titers of all antibodies except anti-EBNA. Thus, VCA-specific IgA and D-specific IgA and IgG became undetectable in t i m e in many of the patients. I n several long-term survivors the declines were arrested a t given levels o r a reversal t o increasing titers was noted which was followed i n time by detection of a recurrent tumor o r metastases in some cases, but not in others who remain under close observation. It would appear that serologic monitoring of NPC patients may warn of recurrent tumor activity well before it becomes clinically evident.

Summary.-The sera of 73 patients with nasopharyngeal carcinoma (NPC), 28 patients with other carcinomas (OC) and 89 healthy subjects (HS) were tested for IgG and IgA antibodies to Epstein-Barr virus (EBV) viral capsid antigen (VCA). The majority of the NPC sera had IgG titres of 160 or above, whereas the majority of the other sera had titres below 160. For IgA reactivity to EBV-VCA,68 of 73 (93*2%) NPC sera had titres of > 10. In contrast, only 6 of 28 (21-4%) OC sera and none of the HS sera had such titres. The mean serum concentrations of IgG, IgA, IgM and C3' were also determined in 55 NPC and 20 OC patients and 18 HS. They were all significantly higher in the NPC sera than in the HS. Although the concentrations of IgG and C3' were not significantly different in the two carcinoma groups, the concentrations of IgA and IgM were significantly higher in the NPC group than in OC. These findings appear to reflect the intensity of EBV-specific antigenic stimulation in NPC, and the EBV-specific serum IgA reactivity may be a useful aid to the diagnosis of NPC, especially in cases with an occult primary tumour. It may be also of value as a screening test in people at high risk.

Summary.-Irrespective of the ethnic origin of the patient, nasopharyngeal carcinoma (NPC), appears to stimulate the production of IgA antibodies against VCA. These antibodies are detected at high frequency and titres in sera from NPC patients but only rarely from control subjects. A majority of relapse-free survivors tested 1-12 years after radiotherapy (RT) sustain a detectable level of IgA anti-VCA. Serum titres of IgA anti-VCA remain relatively unchanged in individual NPC patients after RT, regardless of the disease evolution. These antibodies were detected in serum from one individual 9 months before NPC and the titre rose concomitantly with its clinical onset.

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