[Immunosuppressive acidic protein (IAP) and immunosuppressive substance (ISS) in patients with renal cell carcinoma]

To clarify their usefulness as markers for renal cell carcinoma, serum immunosuppressive acidic protein (IAP) and serum immunosuppressive substance (ISS) were evaluated by TIA (turbidometric immunoassay) for IAP and by SRID (single radial immunodiffusion) for ISS. The mean level of IAP and ISS was beyond each upper normal limit (500, 700 micrograms/ml) in every stage, and especially high in the M1 group. The levels of IAP and ISS were significantly correlated with each other. The determination of IAP and ISS levels after treatment showed a good correlation to the clinical course of the disease. The positive rates of IAP and ISS increased as the stages progressed, respectively. When the influences of pretreatment IAP and ISS level on survival period were investigated, the low IAP or ISS level group (less than two times of the upper normal limit) tended to have a better prognosis than the high level group (more than two times of the upper normal limit) in the M1 patients. These findings suggested that IAP and ISS could be used as markers for monitoring a disease and predicting the prognosis in patients with renal cell carcinoma. As for the positive rate in the combination assay for IAP, TPA and ferritin, or ISS, TPA and ferritin, more than 80% of the patients with low stage renal cell carcinoma had at least one positive marker. This suggested that the combination assay of these three markers was clinically valuable as a disease monitor in patients with renal cell carcinoma.