Circulating immune complexes in patients with melanoma

Sera from 51 melanoma patients and from 55 healthy donors were examined for the presence of immune complexes (ICs) by the EA-rosette forming cell inhibition assay. Using a cut-off point of 5% rosette inhibition, ICs were found in 144 out of 213 sera from patients with melanoma (67.6%) and in 11 out of 55 control subjects (20%, p less than 0.001). The percentage of positive results was significantly lower in patients with no evidence of disease (60%) than in patients with clinical symptoms of their tumor (localized disease -- 80%, p less than 0.02, metastatic disease -- 78%, p less than 0.05). The mean inhibitory rate in patients with metastatic disease (21%) was higher than in patients with localized tumor (15.1%, the difference not significant) and than in patients with no evidence of disease (10%, p less than 0.01). The high levels of ICs or a tendency for their increasing in most cases accompanied the dissemination of the neoplasm. The stabilization of ICs on the low levels was found to be a prognostically favorable sign.