Serial determinations of melanoma tumor-associated antigen and antibody in patients with stage I melanoma

J. H. Wong, R. K. Gupta and D. L. Morton

The correlation of circulating immune complexes (CICs) and the clinical course of malignant melanoma has not been consistent when using nonspecific assays for CIC. To improve predictability, serial serum samples from patients with pathologic stage I melanoma were analyzed for the presence of antimelanoma tumor-associated antigen (TAA) antibody by direct radioimmunoassay and for the presence of melanoma TAA in CIC by the antigen competition method. Immunochemically characterized TAA was isolated from the spent culture medium of a melanoma cell line. Seventy-five percent of patients with melanoma TAA-specific immune complex (IC) had recurrences, while 71% of patients without melanoma TAA-specific IC remained free of disease for prolonged periods (up to 14 years of follow-up). Anti-TAA antibody titers did not correlate with disease recurrence. Our results demonstrate a correlation with melanoma TAA-specific IC and disease recurrence. The absence of melanoma TAA-specific IC is associated with a low risk of recurrence. Fluctuations in melanoma TAA-specific IC levels indicate a dynamic tumor host immunobiology and the need for serial follow-up.