[Clinical evaluation of the serum level of immunosuppressive acidic protein (IAP) and immunosuppressive substance (IS) in gastric cancer patients].

Recently, immunosuppressive acidic protein (IAP) and immunosuppressive substance (IS) were reported by two institutions, and they have been currently under extensive clinical investigations. As these two acidic proteins seemed to be very similar glycoproteins, we tried to elucidate clinically the dissimilarities between these two substances. The mean value of IAP of 106 healthy donors was 378 +/- 100 micrograms/ml, and as 95% of them was under 550 micrograms/ml, therefore, the upper limit of normal value of IAP was determined to be 550 micrograms/ml. On the other hand, the mean value of IS was 553 +/- 125 micrograms/ml and the upper limit of normal value was 750 micrograms/ml. In 110 gastric cancer patients, the incidence of the abnormal value of IS (43%) was higher than that of IAP (33%), and abnormal values were observed at earlier stage in IS than that observed in IAP. The reaction of skin tests was more highly correlated with the value of IS than the value of IAP. From these facts, it was suggested that the value of IS was more predictable than that of IAP as the parameter of the immunosuppression of the gastric cancer patients.