CCL22 and inflammatory skin disease: When the epidermal barrier of the skin is damaged by physical or chemical stimuli, many cytokines (IL-1β, IL-6, TNF-α, IL-5, and TSLP) and chemokines (MCP-1, RNATES, TARC, MDC, CXCL8, and CXCL10) are expressed in stimulated keratinocytes to promote the progression of inflammatory skin diseases [36].