title: Severely photosensitive psoriasis: a phenotypically defined patient subset.
abstract: A subset of patients with chronic plaque psoriasis exhibits severely photosensitive psoriasis (PP) with a pronounced seasonal pattern, but the pathomechanism is not understood. We performed two related studies; first, a detailed clinical characterization of PP, and second, a controlled investigation exploring the underlying pathomechanisms through the assessment of disease onset after photoprovocation. Patients with PP (n=20) showed striking female predominance (19F:1M), very low mean age of psoriasis onset (11 years, range 2-24), family history of psoriasis (13/20), a strong HLA-Cw*0602 association (16/17), and a rapid abnormal clinical response to broadband UVA, comprising erythema+/-scaling plaques (17/20). Subsequently, patients with PP (n=10), non-PP (n=9), and healthy volunteers (n=11) were challenged with low-dose broadband UVA on 3 consecutive days, and serial biopsies were taken after 6 hours to 7 days and from unchallenged skin. Histological changes consistent with early psoriasis occurred in 4 of 10 PP patients, but in neither of the control groups, with significant dermal infiltration by neutrophils, CD4+, CD8+, and CD45RO+ cells at 24 h, accompanied by acanthosis. Thus, a phenotypically distinct subset of psoriasis has been characterized. In contrast with earlier assumptions, UV can provoke psoriasiform features rapidly de novo; a role for memory effector T cells is supported in the early phase.
authors.affiliation: Department of Dermatological Sciences, School of Translational Medicine, University of Manchester, Manchester M6 8HD, UK.
authors.forename: Kirsty J
authors.initials: KJ
authors.lastname: Rutter
authors.forename: Rachel E B
authors.initials: RE
authors.lastname: Watson
authors.forename: Lindsey F
authors.initials: LF
authors.lastname: Cotterell
authors.forename: Thomas
authors.initials: T
authors.lastname: Brenn
authors.forename: Christopher E M
authors.initials: CE
authors.lastname: Griffiths
authors.forename: Lesley E
authors.initials: LE
authors.lastname: Rhodes
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology; D004890:Erythema / Q000209:etiology / Q000473:pathology; D005260:Female; D015236:HLA-C Antigens; D006650:Histocompatibility Testing; D006801:Humans; D007156:Immunologic Memory; D016130:Immunophenotyping; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000473:pathology; D010787:Photosensitivity Disorders / Q000276:immunology* / Q000473:pathology*; D011565:Psoriasis / Q000276:immunology* / Q000473:pathology*; D012621:Seasons; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D015236:HLA-C Antigens; D017493:Leukocyte Common Antigens