Inflammatory Markers Change with Age, but do not Fall Beyond Reported Normal Ranges.

We examined the serum levels of IL-6, IL-8, TNF, IL-6R, TNF-R1, and CRP and the dynamics of changes in these levels according to age. The study included healthy individuals of 20-90 years of age. Participants were divided into subgroups based on their decade of life, and into subgroups of ≥65 or <65 years. Serum cytokine levels were assayed by ELISA, and CRP using an immunoturbidimetric method. Serum CRP levels were within the normal range for all subgroups. The 60- to 70-year age group showed higher CRP than the 20- to 30- (p = 0.003), 30- to 40- (p = 0.009), and 40- to 50- (p = 0.030) year age groups. Serum cytokine levels were low. It was greater in the 60- to 70-year age group than in the 20- to 30- (p = 0.008) and 30- to 40- (p = 0.040) year groups, and was greater in the 70- to 90-year group than the 20- to 30-year group (p = 0.043). Serum TNF-R1 level in the 70- to 90-year group was greater than in all other age groups (p = 0.000 for all comparisons). Other measured parameters did not differ between groups. Serum levels of IL-6, CRP, and TNF-R1 were greater in participants ≥65 than <65 years of age. Healthy older people showed low serum levels of CRP and pro-inflammatory cytokines, but higher than in younger population. Therefore, the adjustment of normal ranges in the elderly should be considered. Serum levels of pro-inflammatory cytokines elevated beyond normal ranges indicate particular diseases.