TNF and Erythema: C. acnes inoculated subcutaneously into the back of the ears induce ear swelling, redness, and erythema [48], which are associated with the local and systemic production of TNF-α, IL-6, and IL-8 [63] as well as the infiltration of CD45+Ly6G+ neutrophils and CD45+F4/80+ macrophages into the infected tissue [62].