PLASMA NEOPTERIN C-REACTIVE PROTEIN RATIO AS AN ADJUNCT TO THE ASSESSMENT OF INFECTION AND CANCER CACHEXIA

Neopterin (NPT), a pteridine intermediate metabolite in the biopterine synthetic pathway, is synthesized and secreted by monocytes/macrophag es upon stimulation, mainly by gamma-interferon produced by activated T cells. C-reactive protein (CRP) is one of the major acute-phase reac tants and its release is thought to be mediated by interleukin-6. Plas ma concentrations of NPT and CRP were synchronously analyzed in 25 det erminations of 5 patients with severe infectious complications and 50 determinations of 10 cancer-burden patients representing cachexia. The mean value of NPT (pmol/ml) was 201.6 in the infection group and 16.5 in the cancer cachexia group. The mean value of CRP (mg/dl) was 12.5 in the infection group and 3.4 in the cancer cachexia group. The numbe r of samples in which NPT alone exceeded the cut-off level were 0/25 ( 0 %) in the infection group and 38/50 (76.0 %) in the cancer cachexia group. The number of samples in which both NPT and CRP exceeded the cu t-off level was 25/25 (100 %) in the infection group and 12/50 (24.0 % ) in the cancer cachexia group. The mean ratio of NPT to CRP was 11.3 in the infection group and 30.7 in the cancer cachexia group, respecti vely. These results suggest that gamma-interferon could play the princ ipal role in the pathogenesis of cancer cachexia and that interleukin- 6 modified the disease status. Interleukin-6 would be the critical med iator of host responses in infectious complications.