Circulating antibodies against human chorionic gonadotropin following trophoblastic disease

The presence of antibodies against human chorionic gonadotropin (hCG) is described in a patient who was treated for persistent trophoblastic disease. These antibodies remained detectable over a 14-month period of observation. In 15 other patients, successfully treated for trophoblastic disease, their presence could not be demonstrated. The binding affinity for labeled hCG was investigated by polyethylene glycol precipitation, by complex formation with protein A-Sepharose, and by gel filtration. Circulating antibodies against hCG may interfere with immunological serum hCG estimations.