title: UV radiation-induced immunosuppression is greater in men and prevented by topical nicotinamide.
abstract: UV radiation-induced immunosuppression augments cutaneous carcinogenesis. The incidence of skin cancer continues to increase despite increased use of sunscreens, which are less effective at preventing immunosuppression than sunburn. Using the Mantoux reaction as a model of skin immunity, we investigated the effects of solar-simulated (ss) UV and its component UVA and UVB wavebands and tested the ability of topical nicotinamide to protect from UV-induced immunosuppression. Healthy, Mantoux-positive volunteers were UV-irradiated on their backs, with 5% nicotinamide or vehicle applied to different sites in a randomized, double-blinded manner. Subsequent Mantoux testing at irradiated and adjacent unirradiated sites enabled measurement of UV-induced immunosuppression with and without nicotinamide. Suberythemal ssUV caused significant immunosuppression, although component UVB and UVA doses delivered independently did not. Men were immunosuppressed by ssUV doses three times lower than those required to immunosuppress women. This may be an important cause of the higher skin cancer incidence and mortality observed in men. Topical nicotinamide prevented immunosuppression, with gene chip microarrays suggesting that the mechanisms of protection may include alterations in complement, energy metabolism and apoptosis pathways. Nicotinamide is a safe and inexpensive compound that could be added to sunscreens or after-sun lotions to improve protection from immunosuppression. immunosuppression.JID JOURNAL CLUB ARTICLE: For questions, answers, and open discussion about this article, please go to http://network.nature.com/group/jidclub
authors: Department of Dermatology, Melanoma and Skin Cancer Research Institute, Sydney Cancer Centre, University of Sydney, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia. diona.damian@email.cs.nsw.gov.au
authors: Diona L
authors: DL
authors: Damian
authors: Clare R S
authors: CR
authors: Patterson
authors: Michael
authors: M
authors: Stapelberg
authors: Joohong
authors: J
authors: Park
authors: Ross St C
authors: RS
authors: Barnetson
authors: Gary M
authors: GM
authors: Halliday
mesh_terms: D000287:Administration, Topical; D000328:Adult; D017209:Apoptosis / Q000235:genetics; D003165:Complement System Proteins / Q000235:genetics; D004734:Energy Metabolism / Q000235:genetics; D004890:Erythema / Q000276:immunology / Q000517:prevention & control; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D007165:Immunosuppression Therapy; D008297:Male; D008875:Middle Aged; D009536:Niacinamide / Q000008:administration & dosage*; D020411:Oligonucleotide Array Sequence Analysis; D012727:Sex Characteristics; D012867:Skin / Q000187:drug effects* / Q000276:immunology* / Q000528:radiation effects; D012878:Skin Neoplasms / Q000276:immunology / Q000517:prevention & control; D013471:Sunburn / Q000276:immunology / Q000517:prevention & control; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014803:Vitamin B Complex / Q000008:administration & dosage*
chemical_list: D014803:Vitamin B Complex; D009536:Niacinamide; D003165:Complement System Proteins