Thirteen patients with a history of confirmed liver carcinoma were given either I131 goat polyclonal or murine monoclonal antibodies against alpha-fetoprotein (AFP), and then scanned with a gamma camera. In order to reduce background, nontarget activity, especially in the liver, blood pool, and reticuloendothelial system, 99mTc imaging agents were used for tumor image enhancement by computer-assisted subtraction. A sensitivity of 91% for the primary site, 50% for the lungs (33% for the chest area), and 75% for the abdomen and pelvis was achieved, with a specificity of 100%, 94%, and 100% for these sites, respectively. The accuracy was determined to be 93% for the liver, 86% for the lungs (77% for the chest), and 85% for the abdominal and pelvic area, resulting in an overall accuracy rate for imaging primary and metastatic hepatocellular cancer of 84% (90% if bone metastases are excluded). In two of the 13 patients, lesions that had been missed by conventional liver scintigraphy and transmission computed tomography (CT) were first shown by radioimmunodetection (RAID).

In vivo reticuloendothelial Fc receptor function was studied in 14 individuals. To assess this function Tc-99m-labeled IgG-coated autologous erythrocytes were injected intravenously and circulatory clearance rates of radioactivity were determined. In 12 individuals [6 normals and 6 patients with systemic lupus erythematosus (SLE)], kinetic computerized scintigraphic imaging of various internal organs was compared to circulatory clearance rates. Both circulatory clearance rates and percentage splenic uptake (PSU) were significantly depressed in patients. The difference between patients and normals was more significant for PSU than for circulatory clearance. Splenic uptake curves showed significantly less linearity for patients, suggesting that splenic defects in SLE are not only quantitative, but also are qualitative. Understanding the nature of immune clearance defects in immune complex mediated diseases may allow for a more rational approach to treatment of patients with these disorders.