In acne vulgaris, the comedogenic action of Cutibacterium acnes on sebum is primarily mediated through which mechanism that drives inflammation?

• A Biofilm formation preventing antibiotic penetration
• B IgE-mediated type I hypersensitivity against sebaceous antigens
• C Production of lipases that cleave triglycerides to pro-inflammatory free fatty acids ✓
• D Activation of complement via the classical pathway

Explanation

C. acnes produces lipases (triglyceride lipase) that hydrolyse sebum triglycerides into glycerol (used by bacteria as nutrients) and free fatty acids (FFA). FFAs are directly comedogenic and pro-inflammatory, inducing TLR-2 activation on keratinocytes and macrophages, leading to IL-1, IL-6, and IL-12 release. This is the primary mechanism by which bacterial colonisation converts the non-inflammatory microcomedo into an inflammatory papule/pustule.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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