CHANGES IN SERUM IMMUNOSUPPRESSIVE ACIDIC PROTEIN FOLLOWING SURGERY IN PATIENTS WITH RENAL-CARCINOMA

Serum immunosuppressive acidic protein (IAP) was measured serially in 69 patients with renal carcinoma who were treated surgically and follo wed up for more than 6 months after surgery. Elevated IAP levels > 600 mu g/ml were seen in 8 of 52 patients without evidence of recurrence and in 5 of 10 patients prior to clinical evidence of recurrence but i n whom recurrence did eventually develop. The positive rate of IAP lev els > 600 mu g/ml in recurrent cases was significantly higher than in non-recurrent ones. In 7 patients with distant metastases, IAP levels rose to > 500 mu g/ml in 3 of 5 patients whose disease progressed desp ite therapy; levels fell to < 600 mu g/ ml in 2 patients who responded to therapy. The data suggest that recurrence should be suspected in p atients with IAP levels > 600 mu g/ml, as these changes appear to corr elate with the response of metastases to therapy.