Antibody-dependent cellular cytotoxicity and disease course in North American patients with nasopharyngeal carcinoma: a prospective study.

Abstract

It has previously been reported that antibody-dependent cellular cytotoxicity (ADCC) levels determined at diagnosis against Epstein-Barr virus (EBV)-specific membrane antigens (MA) are predictive of disease course following therapy in patients with nasopharyngeal carcinoma (NPC). In general, survival was significantly shorter following therapy in patients with low ADCC titers at diagnosis versus those with high titers. To examine this further, a prospective study on North Americans with different histopathological types of this disease was initiated approximately 5 years ago. The results to date tend to support the conclusions drawn from the retrospective study for patients with the more poorly differentiated types (WHO 2 and WHO 3) of this disease. Over the first 3 years of this study, approximately 75% of the patients in the "high" category have remained clinically disease-free for 3 years or longer as opposed to approximately 35% of the patients in the "low" group. Disease progression rates were calculated to be approximately four times higher in the low group. Similar trends were noted in actual survival rates over a 3-year period. ADCC titers were in general found to be relatively stable in sequential serum samples from the same patient, with some exceptions. With the exceptions, however, changes in ADCC titers also reflected disease course. These results indicate, therefore, that anti-EBV ADCC titers are predictive of disease course in patients with the poorly differentiated types of NPC.