title: UV-induced tolerance to a contact allergen is impaired in polymorphic light eruption.
abstract: Polymorphic light eruption (PLE) is a common skin disorder provoked by exposure to UVR. Its clinical symptoms resemble those of a contact allergic reaction. PLE is generally considered a T-cell-mediated autoimmune reaction toward a yet unidentified antigen formed in UVR-exposed skin. Predisposition to such an immune reaction may result from aberrant epitope formation, increased immune reactivity to a universal epitope, or diminished propensity to UVR-induced immunosuppression or to the induction of tolerance. In a study comprising a total of 24 PLE patients and 24 healthy sex- and age-matched controls, we found that both groups demonstrated similar immunosuppression of contact sensitization to diphenylcyclopropenone by earlier exposure to solar-simulating UVR. However, only 1 out of 13 PLE patients (8%) versus 6 out of 11 controls (55%) that had been immunosuppressed by UVR exhibited a state of immunotolerance toward the same allergen after 10-24 months (P=0.023). We conclude that the impaired propensity to UVR-induced allergen-specific immunotolerance may promote recurrent PLE.
authors.affiliation: Department of Dermatology, University of Turku, Turku, Finland. leena.koulu@tyks.fi
authors.forename: Leena M
authors.initials: LM
authors.lastname: Koulu
authors.forename: Jarmo K
authors.initials: JK
authors.lastname: Laihia
authors.forename: Hanna-Helena
authors.initials: HH
authors.lastname: Peltoniemi
authors.forename: Christer T
authors.initials: CT
authors.lastname: Jansén
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology; D003521:Cyclopropanes / Q000008:administration & dosage; D017454:Dermatitis, Photoallergic / Q000276:immunology* / Q000532:radiotherapy*; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology / Q000528:radiation effects*; D007165:Immunosuppression Therapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000008:administration & dosage; D014466:Ultraviolet Rays / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000485:Allergens; D003521:Cyclopropanes; D000939:Epitopes; D017319:Photosensitizing Agents; C029402:diphenylcyclopropenone