RT Journal Article SR Electronic T1 The CD40/CD40 ligand system in the skin of patients with subacute cutaneous lupus erythematosus. JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 2412 OP 2416 VO 34 IS 12 A1 Marzia Caproni A1 Daniele Torchia A1 Emiliano Antiga A1 Barbara Giomi A1 Michele Mercuri A1 Walter Volpi A1 Paolo Fabbri YR 2007 UL http://www.jrheum.org/content/34/12/2412.abstract AB 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. CONCLUSION: 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.