Experimentally induced psoriatic lesions associate with rapid but transient decrease in interleukin-33 immunostaining...

Area of Science:

• Dermatology
• Immunology
• Cell Biology

Background:

• The Köbner reaction is a phenomenon in psoriasis where skin lesions appear at sites of injury.
• Interleukin-33 (IL-33), an alarmin, is a potential mediator in inflammatory skin conditions like psoriasis.

Purpose of the Study:

• To investigate the role of epidermal interleukin-33 (IL-33) in the Köbner reaction of psoriasis.
• To determine if IL-33 released from damaged keratinocytes affects mast cells and other immune cells.

Main Methods:

• Tape stripping was used to induce minor epidermal damage in uninvolved psoriatic skin.
• Skin biopsies were collected at various time points (0 day, 2 h, 1 day, 3 days, 7 days) for immunohistochemistry.
• Keratinocyte cultures were used to assess IL-33 release upon cell damage, and its effect on mast cells and peripheral blood mononuclear cells was evaluated.

Main Results:

• Patients with a positive Köbner reaction showed reduced epidermal thickness and transiently decreased IL-33 immunostaining in biopsies compared to Köbner-negative patients.
• Damaged keratinocytes in culture released full-length IL-33.
• Low concentrations of recombinant human IL-33 (rh-IL-33) stimulated proliferation in LAD2 mast cells but not in psoriatic peripheral blood mononuclear cells.

Conclusions:

• Epidermal IL-33 levels are associated with the Köbner reaction in psoriasis.
• Released IL-33 may contribute to the inflammatory process by stimulating dermal mast cell proliferation.