Document Detail

Topical ALA-PDT produces an inflammatory infiltrate but reduces Langerhans cells in healthy human skin in vivo.
MedLine Citation:
PMID:  21623750     Owner:  NLM     Status:  Publisher    
Background:  Topical photodynamic therapy (PDT) elicits a therapeutic response in both skin cancer and immune-mediated skin disorders. While PDT induces direct cell death, host inflammatory and immune responses to PDT may contribute to the therapeutic effects. Objectives:  To examine the impact of topical PDT on leucocyte trafficking and mediators of chemotaxis in healthy human skin. Methods:  Aminolevulinic acid (ALA)-PDT was performed on the buttock skin of 7 healthy volunteers. Biopsies for immunohistochemical assessment were taken 1, 4 and 24 h post-PDT and from untreated contralateral buttock skin (baseline). Results:  A significant dermal neutrophilic infiltrate appeared early, peaking at 4 h (p<0.01) and returning to near baseline by 24 h. Expression of E-selectin was significantly higher at 4 h (p<0.05) and correlated strongly with neutrophil numbers (r=0.93). Expression of intercellular adhesion molecule 1 was significantly elevated after 24 h (p<0.05) with an apparent gradual increase in CD4(+) T cells up to this time point. Notably, epidermal Langerhans cells were significantly reduced 24 h post-PDT compared to baseline (p<0.01) and comprised a significantly larger proportion of cells with migratory rather than dendritic morphology (p<0.05). The number of epidermal cells expressing tumour necrosis factor-α significantly increased at 4 h (p<0.05) and remained elevated 24 h post-PDT, whereas no significant change in expression of interleukin (IL)-1β or IL-8 was seen. Conclusions:  Reduction of Langerhans cells by topical PDT of human skin may play a significant role in PDT-induced local immunosuppression, potentially benefiting the treatment of immune-mediated skin disorders but negatively impacting on anti-tumour responses. Further exploration according to disease indication/treatment protocol is warranted.
G Evangelou; M D Farrar; R White; N B Sorefan; K P Wright; K McLean; S Andrew; R E B Watson; L E Rhodes
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-5-28
Journal Detail:
Title:  The British journal of dermatology     Volume:  -     ISSN:  1365-2133     ISO Abbreviation:  -     Publication Date:  2011 May 
Date Detail:
Created Date:  2011-5-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0004041     Medline TA:  Br J Dermatol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011 British Association of Dermatologists.
Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester, UK Department of Cellular Pathology, Salford Royal NHS Foundation Hospital, Manchester, UK.
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