Complement activation in acne vulgaris: consumption of complement by comedones.

Area of Science:

• Immunology
• Dermatology
• Microbiology

Background:

• Comedones are a primary feature of acne vulgaris.
• The complement system is crucial for immune responses.
• Previous research suggested a link between acne and immune activation.

Purpose of the Study:

• To investigate the role of comedones in complement activation.
• To identify the specific components within comedones responsible for immune stimulation.
• To elucidate the pathways of complement activation in acne.

Main Methods:

• Assessing complement hemolytic activity in serum incubated with comedones.
• Utilizing serum from healthy individuals and patients with inflammatory acne.
• Employing absorption studies with Propionibacterium acnes.
• Performing immunoelectrophoretic analysis to detect complement component conversion.
• Using ethylene glycol-bis(beta-aminoethyl ether)-N,N'-tetraacetic acid to differentiate complement pathways.

Main Results:

• Comedones consumed complement hemolytic activity in normal serum.
• Serum from inflammatory acne patients enhanced this consumption.
• Propionibacterium acnes absorption removed the stimulating activity.
• Immunoelectrophoresis showed conversion of C3 and factor B, and C4 cleavage, indicating activation of both classical and alternative complement pathways.

Conclusions:

• Comedones can activate the complement system via classical or alternative pathways.
• Propionibacterium acnes within comedones are implicated in complement activation in acne.
• This activation may contribute to the inflammatory processes in acne lesions.