Age-dependent decreases in serum soluble interleukin-1 receptor type I (sIL-1RI) in healthy individuals: a population study of serum sIL-1RI levels in Japanese subjects.

The levels of several soluble cytokine receptors in body fluids of healthy individuals change with age. Clinical application of the measurement of the serum soluble interleukin-1 receptor type I (sIL-1RI) level depends critically on the samples used as the controls. At present, there is no information regarding the levels of serum sIL-1RI in healthy subjects. The purpose of this study is to reveal the age-related changes that occur in the serum sIL-1RIlevels of healthy individuals. We determined the serum sIL-1RI levels of healthy Japanese children using ELISA. The serum sIL-1RI level of children (0-14 years) was significantly higher than that of adults (more than 15 years) (P = 0.0138, n = 90). Thus, it is recommended that when the serum sIL-1RI level of patients is evaluated, it should be compared against age-matched controls. Copyright 2009 Wiley-Liss, Inc.