IL-19 is an IL-10 family cytokine that promotes IL-6 and TNF-α synthesis by binding to high-affinity receptors (composed of IL-20R1 and IL-20R2), inducing monocytes to produce reactive oxygen species and causing Die. Lipopolysaccharide stimulates Epstein-Barr virus-transformed B cells as well as monocytes/macrophages to express this factor.