Regulatory T Cells (Tregs) in Polymorphic Light Eruption
Polymorphic light eruption (PLE) is a photodermatosis with an extremely high prevalence, particularly among young women (up to 20%). The disease is characterized through itchy skin lesions on sun-exposed body sites occurring after sun exposure mostly in spring and early summer. Its etiopathogenesis is unknown but resistance to UV-induced immunosuppression with subsequent immune reactions against skin photoneoantigens has been suggested. Regulatory T cells (CD4+CD25+FoxP3+) (Tregs), a subset of T helper cells, are crucial for the induction of immunosuppression. We will test the hypothesis that PLE patients show pathogenic fluctuating Treg levels and function and related parameters over the seasons of the year, possibly being responsible for lack of immune modulation and autoimmunity in PLE. Natural or medical photohardening may normalize Treg deficiency in PLE and lead to clinical adaption in summer. Better insight into the pathogenesis of PLE may give clues to develop new therapeutic strategies.
Polymorphic Light Eruption
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||Regulatory T Cells (Tregs) in Polymorphic Light Eruption|
- Treg level and function [ Time Frame: Prospective ] [ Designated as safety issue: No ]
- Blood and/or skin cytokine and chemokine levels, vitamin D status, and other immunoregulatory parameters (see above) [ Time Frame: prospective ] [ Designated as safety issue: No ]
Biospecimen Retention: Samples With DNA
|Study Start Date:||March 2008|
|Study Completion Date:||December 2014|
|Primary Completion Date:||December 2014 (Final data collection date for primary outcome measure)|
Patients with polymorphic light eruption without medical photohardening treatment
Patients with polymorphic light eruption treated with medical photohardening
Patients with other disorders (including psoriasis) treated with phototherapy
Normal healthy subjects
PLE patients will be recruited through the Photodermatology Unit of the Department of Dermatology, Medical University of Graz, Graz, Austria. Eligible patients will be identified through diagnosis-related computer-assisted search in the electronic patient chart system of the Unit. The diagnosis of PLE will be verified by patient's history, clinical symptoms, histologic findings, laboratory studies and/or phototesting procedures.
The levels and function of Tregs, memory T cells, neutrophils, mast cells, Langerhans cells, cytokine and chemokine profiles, vitamin D levels in the blood and/or skin will be studied in PLE patients compared to control groups. Volunteers of four groups will be enrolled in this study: i) patients with PLE undergoing preventive medical UV photohardening in spring; ii) PLE patients not undergoing preventive UV photohardening; iii) healthy control subjects; and iv) patients with other diseases (including psoriasis, atopic dermatitis, and other conditions) undergoing therapeutic phototherapy.
Blood will be taken by venous puncture (mainly of a cubital vein) from the individual study participants at four defined time points during the year: (i) spring (March to April) (before medical photohardening in PLE patients); (ii) spring/early summer (April to June) (immediately after medical photohardening of PLE patients); (iii) late summer (August to September); and (iv) late fall (November to December). In addition, optional skin biopsies will be taken to study the parameters listed above. The statistical power analysis (alpha 0.05; power 0.8; assumed difference in Treg level/function of 30% among groups; based on the data by Myara et al., 2005) revealed that 23 patients (21+2 expected drop-outs) need to be enrolled per patient group. All patients of the non-PLE groups will be sex- and age (plus/minus 5 years)-matched to the PLE subjects.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00555178
|Medical University of Graz|
|Graz, Austria, A-8036|
|Medical University of Graz, Department of Dermatology|
|Graz, Austria, 8036|
|Principal Investigator:||Peter Wolf, MD||Medical University of Graz|