LIF and infection: Interestingly, in the case of previously-infected younger individuals, who showed at least 8.8-fold increase of antibody response compared to their counterparts from the infection-naïve group associated a significant reduction in the concentration of proinflammatory biomarkers (negative factors: MCP-1, CRP, factor D, PAI-1), concomitant with an increase in the serum levels of other adipokines, such as adiponectin, leptin, IL-6, and IL-10.