TLR2 and acne: P. acnes plays a direct role in the inflammatory response in acne by activating the innate immune system via the Toll-like receptor pathway (TLR2) on keratinocytes and the sebocytes of the pilosebaceous unit, thus activating signalling cascades and inducing the release of inflammatory mediators such as IL1ß, TNF-α, IL8 (CXCL8), and IL6 [35, 36].