Interleukin-1 and interleukin-6 in psoriasis

Area of Science:

• Dermatology
• Immunology
• Molecular Biology

Background:

• Psoriasis is a chronic inflammatory skin disease characterized by aberrant immune responses.
• Interleukins, such as IL-1 and IL-6, play crucial roles in inflammation and immune cell regulation.
• Understanding the localized expression of these cytokines in psoriatic skin is vital for elucidating disease mechanisms.

Purpose of the Study:

• To investigate the expression levels and localization of Interleukin-1 beta (IL-1 beta) and Interleukin-6 (IL-6) in psoriatic skin lesions and uninvolved skin.
• To compare cytokine expression in lesional skin with healthy individuals and explore potential cellular sources within the skin.

Main Methods:

• Measurement of IL-1 beta and IL-6 in suction blister fluid using ELISA and bio-assays.
• Immunohistochemical analysis of IL-1 beta and IL-6 in skin sections using specific antibodies.
• Determination of IL-1 and IL-6 mRNA expression in cultured keratinocytes (KC) and fibroblasts from psoriasis and healthy skin.

Main Results:

• IL-1 beta was undetectable in blister fluid from psoriatic lesions, but showed intracellular and membrane staining in epidermal cells and diffuse epidermal staining in uninvolved skin.
• Low levels of IL-6 were detected in blister fluid from psoriatic lesions, while serum IL-6 was undetectable.
• Cultured keratinocytes from psoriasis lesions showed slightly elevated IL-1 beta mRNA, but minimal IL-6 mRNA. Fibroblasts from psoriasis lesions expressed high levels of IL-6 mRNA.

Conclusions:

• Psoriatic skin exhibits a paradoxical IL-1 beta expression pattern, with absence in blister fluid but presence in epidermal cells.
• Dermal fibroblasts, alongside inflammatory infiltrates, are likely significant contributors to IL-6 production in active psoriasis lesions.
• These findings offer insights into the localized cytokine milieu of psoriatic skin and potential therapeutic targets.