The Detection and Clinical Significance of Antibodies to Tumor-Associated Antigens in Patients with Renal Cell Carcinoma

Antibodies against renal carcinoma cells were detected by a microcomplement fixation assay in the sera of 94 per cent of 75 patients with recently resected, localized or metastatic disease, and in 20 per cent of normal controls. Absorption of sera with pooled normal kidney cells abrogated reactivity against normal kidney cells but did not decrease reactivity significantly against the renal carcinoma cells. Analyses of sequential serum samples revealed that after nephrectomy in 9 of 10 patients free of tumor but a high risk for recurrence antibody levels decreased or disappeared by 1 year. However, these levels remained elevated in 2 patients who subsequently were found to have occult persistent tumor. Antibody titers in patients with metastatic renal cell carcinoma declined as the disease progressed. Patients with persistently elevated titers had the longest survival. Although the antibodies detected by this assay may not be specific for renal cell carcinoma, their detection may be of clinical significance with regard to the prognosis of the disease.