Serum cytokine profiles in healthy young and elderly population assessed using multiplexed bead-based immunoassays

BACKGROUND: Lipid metabolites and cytokines, including chemokines and growth factors, are the key regulators of immune cell function and differentiation, and thus, dysregulation of these regulators is associated with various human diseases. However, previous studies demonstrating a positive correlation of cytokine levels with aging may have been influenced by various environmental factors and underlying diseases. Also, data regarding cytokine profiling in the elderly are limited to a small subset of cytokines. METHODS: We compared the profiles of 22 cytokines, including chemokines and growth factors, in a case-controlled study group of a gender-matched, healthy cohort of 55 patients over the age of 65 and 55 patients under the age of 45. Assessment of serum cytokine concentrations was performed using commercially-available multiplex bead-based sandwich immunoassays. RESULTS: Soluble CD40 ligand (sCD40L) and transforming growth factor alpha (TGF-α) levels were significantly higher in the elderly patients, whereas granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein-1 (MCP-1) levels were significantly lower in the elderly patients. The partial correlation analysis demonstrating the correlation between cytokine levels when controlled for gender, systolic blood pressure, total cholesterol, HDL cholesterol, triglyceride, and serum creatinine levels further demonstrated that G-CSF, GM-CSF, and MCP-1 had significant negative correlations with age, whereas sCD40L and TGF-α had significant positive correlations. CONCLUSIONS: Future studies will focus on examining the significance of these age-related changes in circulating cytokines and other biological markers and their potential contribution to the development of different age-associated diseases.