Activation of complement in the skin after PUVA therapy

Area of Science:

• Dermatology
• Immunology
• Photobiology

Background:

• Complement activation is a key immune response.
• Ultraviolet (UV) radiation can trigger immune reactions in the skin.
• Delayed erythema after UV exposure suggests inflammatory processes.

Purpose of the Study:

• To investigate complement activation following UVA and PUVA treatment.
• To determine if complement C3 split products increase after UV irradiation.
• To explore the role of complement in UV-induced delayed erythema.

Main Methods:

• Collected suction blister fluid from the abdominal skin of 14 healthy subjects.
• Measured split products of complement C3 (C3-split) as a marker of complement activation.
• Analyzed C3-split levels before and after UVA or PUVA treatment in both irradiated and non-irradiated skin areas.

Main Results:

• PUVA treatment led to a significant increase in C3-split products (p < 0.05) in both irradiated and non-irradiated skin.
• UVA treatment resulted in a less pronounced increase in C3-split products compared to PUVA.
• Elevated C3-split levels suggest complement activation occurred after UV exposure.

Conclusions:

• Complement activation, indicated by increased C3-split products, is associated with PUVA therapy.
• Complement activation may play a significant role in the delayed erythema observed after long-wave UV light exposure.
• These findings highlight the involvement of the complement system in the skin's response to phototherapy.