Topical photodynamic therapy significantly reduces epidermal Langerhans cells during clinical treatment of basal cell carcinoma

Authors

  • G. Evangelou,

    1. Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester M6 6HD, U.K.
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  • M.D. Farrar,

    1. Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester M6 6HD, U.K.
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  • L. Cotterell,

    1. Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester M6 6HD, U.K.
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  • S. Andrew,

    1. Department of Cellular Pathology, Salford Royal NHS Foundation Hospital, Manchester, U.K.
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  • A.D. Tosca,

    1. University Hospital of Crete, Heraklion, Crete, Greece
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  • R.E.B. Watson,

    1. Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester M6 6HD, U.K.
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  • L.E. Rhodes

    1. Dermatological Sciences, Inflammation Sciences Research Group, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester M6 6HD, U.K.
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  • Funding sources
    None.

  • Conflicts of interest
    None declared.

Lesley E. Rhodes.
E-mail: lesley.e.rhodes@manchester.ac.uk

Summary

Background  Topical photodynamic therapy (PDT) is a widely applied treatment for basal cell carcinoma (BCC). PDT-induced immunosuppression leading to reduced antitumour immune responses may be a factor in treatment failure.

Objectives  To examine the impact of topical PDT on leucocyte trafficking following clinical treatment of BCC.

Methods  Superficial BCCs in eight white caucasian patients were treated with methyl aminolaevulinate (MAL)-PDT. Biopsies for immunohistochemical assessment were taken from BCCs pre-PDT, 1 h and 24 h post-PDT and from untreated healthy skin.

Results  Treatment of BCC with MAL-PDT produced a rapid neutrophil infiltration, commencing by 1 h and significantly increased at 24 h post-PDT (P < 0·05 compared with baseline). An associated increase in the number of blood vessels expressing E-selectin was observed at 1 h and 24 h post-PDT (both P < 0·05 compared with baseline). In contrast, the number of epidermal Langerhans cells fell sharply by 1 h post-PDT, and remained significantly reduced at 24 h post-PDT (both P < 0·05 compared with baseline).

Conclusions  Reduction of Langerhans cells during clinical treatment of BCC might potentially impact negatively on antitumour responses through reduced activation of tumour-specific effector cells. Investigation of modified PDT protocols with the aim to minimize immunosuppressive effects while maintaining antitumour efficacy is warranted.

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