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The Goeckerman Regimen for the Treatment of Moderate to Severe Psoriasis
11:39

The Goeckerman Regimen for the Treatment of Moderate to Severe Psoriasis

Published on: July 11, 2013

Photoinduced cutaneous inflammatory response by psoralens

J R Kumar1, N S Ranadive, I A Menon

  • 1Department of Pathology, University of Toronto, Ont., Canada.

Journal of Photochemistry and Photobiology. B, Biology
|June 30, 1992
PubMed

Insights

This study investigated the inflammatory skin response to 8-methoxypsoralen (8-MOP) and UV light in rabbits. Findings indicate erythema is not directly linked to increased vascular permeability or polymorphonuclear leucocyte accumulation.

Area of Science:

  • Dermatology
  • Photobiology
  • Immunology

Background:

  • Topical 8-methoxypsoralen (8-MOP) combined with UVA-visible irradiation is a known photosensitizing treatment.
  • Understanding the precise inflammatory mechanisms, including vascular permeability and leukocyte infiltration, is crucial for optimizing photochemotherapy.

Purpose of the Study:

  • To characterize the inflammatory skin response in rabbits following topical 8-MOP and UVA-visible irradiation.
  • To quantify increases in vascular permeability (iVP) and polymorphonuclear leucocyte accumulation (aPMN) in relation to erythema.
  • To assess the impact of 8-MOP concentration, irradiation dose, and repeated exposures on these inflammatory markers.

Main Methods:

  • Rabbits received topical 8-MOP cream followed by UVA-visible irradiation.
  • 125I-albumin and 51Cr-labelled PMNs were used to quantify iVP and aPMN, respectively.
  • Erythema was visually graded, and responses were measured at 6, 24, 48, and 72 hours post-irradiation.

Main Results:

  • Peak iVP and aPMN occurred at 24 hours post-irradiation, while erythema peaked between 24-48 hours.
  • Responses were dose-dependent on both 8-MOP concentration and irradiation.
  • Repeated exposures led to reduced iVP and aPMN but persistent erythema, suggesting desensitization.
  • Erythema was observable later and subsided slower than iVP and aPMN.

Conclusions:

  • The study suggests that the visible erythemal response in 8-MOP-induced phototoxicity is not directly correlated with increased vascular permeability or polymorphonuclear leucocyte accumulation.
  • These findings highlight a potential dissociation between the clinical sign of redness and specific cellular/vascular inflammatory events.

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