[Study of filaggrin in psoriasis]

Area of Science:

• Dermatology
• Biochemistry
• Immunohistochemistry

Background:

• Filaggrin is a histidine-rich protein crucial for epidermal differentiation and barrier function.
• Profilaggrin, its precursor, is processed into filaggrin in granular and cornified cells.
• Filaggrin catabolism yields urocanic acid (UV absorption) and pyrrolidone carboxylic acid (hydration).

Purpose of the Study:

• To investigate the localization of filaggrin in normal and psoriatic human skin.
• To assess filaggrin expression changes following treatments for psoriasis.

Main Methods:

• Direct immunofluorescence and immunoperoxidase staining using rabbit anti-human filaggrin antiserum.
• Analysis of skin sections from normal individuals and psoriasis patients before and after treatment.

Main Results:

• Filaggrin was detected in the granular layer and stratum corneum of normal skin.
• No filaggrin staining was observed in untreated psoriatic skin sections.
• Filaggrin reappeared in psoriatic skin sections that achieved complete clinical remission after treatment.

Conclusions:

• Human skin filaggrin expression is significantly reduced or absent in active psoriasis.
• Filaggrin presence correlates with clinical remission, suggesting its potential as a biomarker for psoriasis treatment efficacy.