Serum Neopterin as a Parameter for Monitoring the Course of Renal Cell Carcinoma during Interferon-γ Therapy

Abstract

Serum analyses were performed regularly over 1 year of therapy with bioactive doses of recombinant interferon-γ (mean 200 μg) in eight patients with advanced renal cell carcinoma in order to assess the usefulness of neopterin in monitoring the course of disease. The baseline level calculated from repeated measurements before treatment (2.87 + 0.59 nmol/liter) did not correlate with the extent of metastatic spread. All patients did show significant increases in serum neopterin concentrations 48 hr after IFN application (7.09 ± 1.99 nmol/liter, P < 0.05, t test) in accordance with a temporary IFN-γ-induced reinforcement of macrophage activity. However, no difference was observable when comparing the baseline values to those obtained 1 week after the last IFN application (3.05 ± 1.16 nmol/liter). There was no correlation with the course of disease, i.e., neither with response ( n = 1) nor with progression ( n = 7). in contrast to previous studies, the present report shows that although serum neopterin is an appropriate marker for IFN-γ-induced reinforcement of monocyte/macrophage activity, it is not suitable for monitoring the course of metastatic renal cell carcinoma.