Photohardening of polymorphic light eruption patients decreases baseline epidermal Langerhans cell density while increasing mast cell numbers in the papillary dermis.
The pathogenesis of polymorphic light eruption (PLE) has been linked to a lack of UV-induced immune suppression. To determine the role of Langerhans cells (LC), mast cells and regulatory T cells, biopsies from PLE patients were taken from exposed sites in spring before and after photohardening with 311 nm or PUVA as well as again in summer. Skin sections were assessed for the presence of Langerin/CD1a+ LC and CD3+, CD4+, CD25+ or FoxP3+ T cells and mast cells. Photohardening transiently decreased the density of epidermal LC and significantly increased a low baseline mast cell density in the papillary dermis of PLE patients. Baseline T cell numbers in the skin were low, and there was no difference in PLE patients among any time point. This suggests that LC suppression together with recruitment of mast cells into photohardened skin may be a key cellular event underlying the mechanism by which phototherapy protects from PLE.
Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria.
Peter
P
Wolf
Alexandra
A
Gruber-Wackernagel
Isabella
I
Bambach
Ulrike
U
Schmidbauer
Gerlinde
G
Mayer
Markus
M
Absenger
Eleonore
E
Fröhlich
Scott N
SN
Byrne
D000328:Adult; D001706:Biopsy; D016022:Case-Control Studies; D002452:Cell Count; D020405:Dermis / Q000473:pathology* / Q000528:radiation effects; D005260:Female; D006801:Humans; D007801:Langerhans Cells / Q000473:pathology* / Q000528:radiation effects; D008407:Mast Cells / Q000473:pathology* / Q000528:radiation effects; D008875:Middle Aged; D011701:PUVA Therapy; D010787:Photosensitivity Disorders / Q000473:pathology* / Q000628:therapy*; D010789:Phototherapy; D012873:Skin Diseases, Genetic / Q000473:pathology* / Q000628:therapy*; D050378:T-Lymphocytes, Regulatory / Q000473:pathology / Q000528:radiation effects; D016896:Treatment Outcome; D014466:Ultraviolet Rays
cytokines; immune suppression; mast cells; phototherapy; polymorphic light eruption