Serum levels of cancer antigen 125 and interleukin-15 in relation to the nutrition status of peritoneal dialysis patients.

The concentration of cancer antigen 125 (CA125) in dialysis effluent is considered a marker of mesothelial cell mass, and its concentration in serum is considered a nonspecific marker of peritoneal irritation. Interleukin-15 (IL-15) is a proinflammatory cytokine, playing a role in the initiation of an inflammatory state and supporting the continuation of that state by its influence on the production of other cytokines and on the function of neutrophils, natural killer cells, and T and B cells. In the present study, we performed a correlation analysis between serum CA125, IL-15, and parameters of nutrition in peritoneal dialysis (PD) patients. We measured IL-15 and CA125 in the serum of 42 patients without clinical signs of infection [age: 52.3 +/- 14.4 years; time on PD: 24.5 +/- 20.1 months (range: 0.4 - 72.8 months)]. The IL-15 levels were estimated by ELISA (IBL, Hamburg, Germany) and CA125 levels by immunoenzymatic assay (Roche Diagnostics, Warsaw, Poland). Serum IL-15 concentration was 78.9 +/- 163.4 pg/mL (median: 25.0 pg/mL; range: 0.0- 857.1 pg/mL), and serum CA125 concentration was 20.0 +/- 18.6 U/mL (median: 15.1 U/mL; range: 5.6- 119.1 U/mL). Serum IL-15 concentration showed a significant correlation with serum albumin concentration (r = -0.442, p = 0.003). Serum CA125 concentration correlated with total creatinine clearance (r = -0.322, p = 0.037), lean body mass (r = -0.414, p = 0.007), total body mass (r = -0.360, p = 0.019), total body water (r = -0.436, p = 004 0.004), body surface area (r = -0.368, p = 0.018), serum iron concentration (r = -0.378, p = 0.014), transferrin saturation (r = -0.436, p = 0.004), mean cell hemoglobin concentration (r = -0.324, p = 0.036), and serum albumin concentration as a percentage of total protein level (r = -0.547, p = 0.002). We conclude that, in PD patients, elevated serum IL-15 and CA125 suggest a persistent inflammatory state that negatively influences nutrition status.