Abstract
Cytokines play critical roles in regulating the antibody response to vaccines. We sought to understand the role of endogenous cytokines in the determination of antibody production in the elderly, a group of subjects known to have a lower response rate to vaccination. We found that in a healthy elderly group, only 52% of whom responded to the influenza vaccine, endogenous levels of interleukin 6 (IL-6), IL-10 and gamma interferon (IFNγ) did not differ statistically significantly between responders and non-responders (responders: n = 27, IL-6 = 293 ± 101 pg/ml, IL-10 = 882 ± 240 pg/ml; non-responders: n = 26, IL-6 = 223 ± 71 pg/ml, P = 0.57, IL-10 = 445 ± 148 pg/ml, mean ± SE, P = 0.14, respectively, and undetectable IFNγ). Serum levels of these three cytokines were not changed significantly four weeks after vaccination (P < 0.05 for IL-6 and P < 0.01 for IL-10). In addition, there were also no age-dependent differences in serum IL-6 and IL-10 levels.