Clinical Significance of Soluble Interleukin-2 Receptor as a Putative Systemic Nutritional Index in the Elderly

Abstract

The clinical significance of a slight increase of serum soluble interleukin-2 receptor (sIL2R) concentration in the stable elderly was investigated. Thirty-five residents of nursing homes with physical impairment as a sequel to cerebral infarctions, without any inflammatory condition, anodyne or immunological treatment, were divided into two groups: 24 without overt or suspected malignancy (NC) and 11 with a history of malignancy (CA). Serological screening with measurement of sIL2 R concentrations was performed and numbers of lymphocytes with CD4, CD8 markers were determined. The NC group was divided into controls (n=15, sIL2R<=883U/mL) and subjects demonstrating elevation (n=9, NH), as in a previous study. Differences were found in serum concentrations of albumin, blood urea nitrogen, total cholesterol concentration, Pettigrew's prognostic nutritional index (PNI), as well as the ADL score, but not age or sex between NH and controls. Factor analysis in NC revealed serum creatinine and blood urea nitrogen concentrations to correlate positively, and serum albumin, total cholesterol concentrations, ADL score, PNI to correlate negatively to sIL2R. Differences were found in sIL2R, albumin, total protein, total cholesterol, β-lipoprotein, PNI between CA and controls, but correlations were not found in CA. Survival rate of controls over twenty-four months was better than that of NH, but not of CA. Our results suggest that a slight increase of concentration of sIL2R is related to subclinical systemic deterioration, especially with regard to nutrition, with a plausible connection to prognosis of the stable elderly without malignancy.