Elevated serum concentration of interleukin-1 receptor antagonist (IL-1ra) is correlated to interleukin-6 and to hypoalbuminemia in cachectic patients with colorectal cancer

Background. The mechanisms leading to the development of cancer cachexia are still not well understood. Some important factors, including cytokines and growth factors, are involved, and recently, cytokines such as interleukin-1 and interleukin-6 have been reported to be involved as mediators of this disorder. Methods. In patients with colorectal cancer, serum concentrations of interleukin-1 receptor antagonist (IL-1ra) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA) and analyzed in relation to the patient's nutrition (in terms of albumin concentration [percentage of total protein] in the serum) and the tumor load. Results. The concentration of IL-1ra was significantly increased in cachectic patients compared with that in healthy volunteers and in the non-cachectic patients, and the concentration was correlated to the serum concentration of IL-6 and inversely correlated to the concentration of albumin (%). These concentrations, however, did not correlate to levels of tumor markers tested, ie, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA)19-9. Conclusion. It was shown that the serum concentration of IL-1ra was a useful indicator for cancer cachexia and hypoalbuminemia; IL-1ra seems to be produced by immune-regulating host cells rather than by neoplastic cells.[PUBLICATION ABSTRACT]