Modulation of cathepsin G expression in severe atopic dermatitis following medium-dose UVA1 phototherapy.
BACKGROUND
During the last decade, medium-dose UVA1 phototherapy (50 J/cm2) has achieved great value within the treatment of severe atopic dermatitis (AD). The purpose of our study was to investigate to what extent UVA1 irradiation is able to modulate the status of protease activity by the use of a monoclonal antibody labeling cathepsin G.


METHODS
In order to further elucidate the mechanisms by which medium-dose UVA1 irradiation leads to an improvement of skin status in patients with AD, biopsy specimens from 15 patients before and after treatment were analyzed immunohistochemically for proteolytic activation.


RESULTS
Compared to lesional skin of patients with AD before UVA1 irradiation, the number of cells positive for cathepsin G within the dermal infiltrate decreased significantly after treatment. The decrease of cathepsin G+ cells was closely linked to a substantial clinical improvement in skin condition.


CONCLUSIONS
In summary, our findings demonstrated that medium-dose UVA1 irradiation leads to a modulation of the expression of cathepsin G in the dermal inflammatory infiltrate in patients with severe AD. Cathepsin G may attack laminin, proteoglycans, collagen I and insoluble fibronectin, to provoke proinflammatory events, to degrade the basement membrane, to destroy the tissue inhibitor of metalloproteinases and to increase the endothelial permeability. Therefore, its down-regulation by UVA1 phototherapy may induce the reduction of skin inflammation as well as improvement of the skin condition.
Department of Dermatology, Ruhr-University Bochum, Gudrunstrasse 56, D-44791 Bochum, Germany. Frank.Breuckmann@ruhr-uni-bochum.de
Frank
F
Breuckmann
Gregor
G
von Kobyletzki
Annelies
A
Avermaete
Alexander
A
Kreuter
Peter
P
Altmeyer
Thilo
T
Gambichler
D001706:Biopsy; D017252:CD3 Complex / Q000032:analysis; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism*; D003876:Dermatitis, Atopic / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D012697:Serine Endopeptidases; D012867:Skin / Q000276:immunology / Q000378:metabolism; D014467:Ultraviolet Therapy
D017252:CD3 Complex; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G