The tumour necrosis factor-α inhibitor adalimumab rapidly reverses the decrease in epidermal Langerhans cell density in psoriatic plaques

K. B. Gordon, B. K. Bonish, T. Patel, C. L. Leonardit, Brian J. Nickoloff*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


Background: The pathophysiology of psoriasis is poorly understood, and the mechanism of action of biological agents interfering with tumour necrosis factor (TNF)-α that improve psoriatic plaques is completely unknown. Objectives: To begin to unravel the mechanism of action, cellular changes occurring in plaques following administration of adalimumab, a humanized monoclonal antibody against TNF-α, were investigated. Methods: Thirteen different patients underwent sequential biopsies as part of a clinical trial. Each biopsy was immunostained and evaluated to calculate the relative density of epidermal Langerhans cells (LCs) before and after treatment (days 2, 7, 28, 84). To explore the basis for reduced epidermal LC densities in plaques, a SCID-Hu animal model was utilized. Acute psoriatic lesions were created within 2 weeks by injection of superantigen-activated CD4+ T cells into engrafted symptomless skin. Results: Compared with symptomless skin, untreated plaques had a significantly reduced density of epidermal LCs. There was a rapid increase in density of epidermal LCs in plaques following treatment with adalimumab beginning as early as day 7. The paucity of epidermal LCs in plaques was contrasted to the prominent density of LCs in other skin disorders with chronic inflammation and alterations in keratinization, including lichen planus and inflamed seborrhoeic keratosis. Rapid creation of plaques using the SCID-Hu model was accompanied by loss of epidermal LCs, indicating that diminished LC density occurs at an early stage of lesion formation. Conclusions: These data shed light on a new immunopathological perspective high-lighting a rapid loss of epidermal LCs in acute psoriatic lesions, with sustained decreased density of LCs in chronic plaques. Furthermore, an unexpected insight into the mechanism of action was uncovered for adalimumab, in which rapid restoration of epidermal LC density was observed.

Original languageEnglish (US)
Pages (from-to)945-953
Number of pages9
JournalBritish Journal of Dermatology
Issue number5
StatePublished - Nov 2005


  • Adalimumab
  • Langerhans cells
  • Psoriasis
  • SCID-Hu xenograft mice
  • Tumour necrosis factor-α

ASJC Scopus subject areas

  • Dermatology

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