Ultraviolet-radiation-induced erythema and suppression of contact hypersensitivity responses in patients with polymorphic light eruption.
Ultraviolet-radiation suppresses cell-mediated immunity in healthy humans. It has been postulated that, in the short term, this immunosuppression prevents autoimmune responses to ultraviolet-radiation damaged skin. Patients with polymorphic light eruption (PLE) demonstrate abnormal responses to ultraviolet-radiation suggestive of an immune response to an ultraviolet-radiation-induced antigen. We investigated whether PLE patients (n=22) were resistant to ultraviolet-radiation-induced immunosuppression compared to skin-type, aged-matched controls (n=23). Groups of patients and controls (six subjects per group) received a single dose of solar-simulated ultraviolet-radiation of either 0, 0.6, 1 or 2 minimal erythema doses (MED). Erythema was quantified using a reflectance meter and all volunteers were sensitised on the irradiated site with dinitrochlorobenzene. Contact hypersensitivity responses (CHS) to dinitrochlorobenzene were quantified after challenge using ultrasound. Ultraviolet-radiation-induced erythema was comparable in patients and controls. CHS was comparable in unirradiated patients and controls. UVR-induced a dose-dependent suppression of CHS in all volunteers but patients were more resistant to immunosuppression after 1MED. Exposure to 1MED suppressed CHS by 78% in controls but induced less suppression in patients (44%, p < 0.01). Our data suggest that PLE patients have a flaw in their immunoregulatory response to ultraviolet-radiation it is only apparent over a narrow dose range around 1 MED.
Department of Environmental Dermatology, Photobiology Unit, Division of Skin Sciences, Guy's, King's, and St Thomas' School of Medicine, King's College London, St Thomas' Hospital, London, UK.
Chantalle B
CB
van de Pas
Deirdre A
DA
Kelly
Paul T
PT
Seed
Antony R
AR
Young
John L M
JL
Hawk
Susan L
SL
Walker
D000328:Adult; D017453:Dermatitis, Irritant / Q000276:immunology*; D017454:Dermatitis, Photoallergic / Q000276:immunology*; D004137:Dinitrochlorobenzene; D004890:Erythema / Q000276:immunology*; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology / Q000528:radiation effects; D007165:Immunosuppression Therapy; D007509:Irritants; D008297:Male; D013471:Sunburn / Q000276:immunology; D014466:Ultraviolet Rays / Q000009:adverse effects*
D004137:Dinitrochlorobenzene; D007509:Irritants