CXCL8 and immune system disorder: Some proinflammatory cytokines, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor α (TNF-α), which usually are termed as ‘bad guys’, are reported to correlate with inflammation response and immune regulation as well as several immune diseases [12].