AGE-DEPENDENT PATTERNS OF THE BASELINE CYTOKINE LEVELS IN UNSTIMULATED PERIPHERAL BLOOD SAMPLES

Abstract

The cytokine levels in unstimulated peripheral blood samples differ in relation to age, living conditions (environmental situation, state of medical care, quality of life, etc). Thus, the essential task is to determine normal levels of peripheral blood cytokines for different age groups with respect to regional characteristics. This study aimed to investigate age-associated patterns of the baseline levels for some cytokines in unstimulated peripheral blood samples in healthy children and adults. The studies were carried out at the Laboratory of Clinical Immunology (Clinical and Diagnostic Centre, Yekaterinburg). Peripheral blood samples were taken in 149 healthy children aged from 7 months to 18 years. Group 1 was 7 to 12 months old (29 infants); group 2 was 1 to 3 years old (33 children); group 3 was 4 to 7 years old (29 children); 4th group was 8 to 14 years old (26 children); 5th group, 15 to 18 years old (32 children); and 6th group included 42 adults (19 to 45 years old). The concentrations of TNFα, IFNγ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, and IL-18 in blood serum were determined by common ELISA technique using Vector-Best kits (Novosibirsk, Russia). Analysis of the data made it possible to identify various patterns of age-dependent changes of baseline levels for the determined cytokines: IL-2 showed an increase in concentration by the age of 1-3 years, stable contents up to 18 years, and decreased concentrations in adulthood. IFNγ was at zero levels in children and adolescents, followed by increased levels in adults. IL-4 and IL-6 showed consistently low levels in children and adolescents, with a decrease to zero levels in adult subjects. IL-18, TNFα were at maximal levels at the age of below 7 years followed by a decrease in concentration; IL-1β, IL-17 exhibited bimodal changes, with maximal contents at the age of 1-3 years, and repeated increase in adult age. Nearly stable baseline concentration was noted for IL-10, with a slight increase at 1-3 years, like as for IL-8, with a moderate increase at 15-18 years. For majority of analyzed cytokines, the maximal baseline contents in unstimulated peripheral blood samples were found in children aged 1-3 years. © 2021, RSI