The CD40/CD40 ligand system in the skin of patients with subacute cutaneous lupus erythematosus.
OBJECTIVE
To investigate whether CD40 and CD40 ligand (CD40L) is expressed in the skin of patients with subacute cutaneous lupus erythematosus (SCLE).


METHODS
Six female patients with SCLE were studied. Skin biopsies were obtained from lesional and healthy sunprotected skin. Frozen sections were stained immunohistochemically using monoclonal antibodies to CD4, CD40, and CD40L. As controls we used 5 patients with discoid LE (DLE), 5 with dermatomyositis (DM), 3 with lichen planus (LP), and 2 with erythema multiforme (EM), as well as the normal-appearing skin of 5 healthy volunteers.


RESULTS
The CD40 was intensely expressed in all SCLE, DLE, and DM lesions, and only focally in healthy sunprotected skin specimens. The number of CD40+ cells in SCLE dermis was lower than in DLE, similar to that in DM, LP and EM, and higher than in SCLE sunprotected skin. CD40L+ cells infiltrated the SCLE, DLE, DM, LP, and EM lesional dermis, and were more numerous in SCLE lesional skin than in SCLE healthy sunprotected skin.


CONCLUSIONS
We showed that the CD40/CD40L system may represent an important pathway of induction of SCLE lesions. The expression of such costimulatory system in healthy sunprotected skin also may signify that its abnormal activation is constitutive in SCLE, as previously observed in systemic LE.
Department of Dermatological Sciences, University of Florence, Florence, Italy.
Marzia
M
Caproni
Daniele
D
Torchia
Emiliano
E
Antiga
Barbara
B
Giomi
Michele
M
Mercuri
Walter
W
Volpi
Paolo
P
Fabbri
D000328:Adult; D019013:CD40 Antigens / Q000096:biosynthesis / Q000276:immunology*; D023201:CD40 Ligand / Q000096:biosynthesis / Q000276:immunology*; D016022:Case-Control Studies; D003882:Dermatomyositis / Q000276:immunology; D004892:Erythema Multiforme / Q000276:immunology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008010:Lichen Planus / Q000276:immunology; D008178:Lupus Erythematosus, Cutaneous / Q000276:immunology*; D008179:Lupus Erythematosus, Discoid / Q000276:immunology; D012867:Skin / Q000276:immunology*
D019013:CD40 Antigens; D023201:CD40 Ligand