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.

Infrequent p53 gene mutation but UV gradient-like p53 protein positivity in keloids.

Keloids are characterized by extreme fibroblastic overgrowth of unknown pathogenesis after skin injury. Previous studies, mostly in non-Caucasian populations, suggest that p53 mutations may be involved. To substantiate this, we performed DNA sequence analysis of exons 4-8 of the p53 gene and immunohistochemical staining of p53 protein in archived keloidal tissue samples from 23 Caucasian patients.

8-methoxypsoralen plus ultraviolet A therapy acts via inhibition of the IL-23/Th17 axis and induction of Foxp3+ regulatory T cells involving CTLA4 signaling in a psoriasis-like skin disorder.

To elucidate the molecular action of 8-methoxypsoralen plus UVA (PUVA), a standard dermatological therapy, we used K5.hTGF-beta1 transgenic mice exhibiting a skin phenotype and cytokine abnormalities with strong similarities to human psoriasis. We observed that impaired function of CD4+CD25+ regulatory T cells (Tregs) and increased cytokine levels of the IL-23/Th17 pathway were responsible for the psoriatic phenotype in this mouse model.

Profiles of chemokine receptors in melanocytic lesions: de novo expression of CXCR6 in melanoma.

Selective expression of certain chemokine receptors by melanoma cells and the presence of their ligands in tissues might govern organ site-specific metastasis. Because the expression profile of chemokine receptors in tissues of melanocytic origin is unknown, we performed a comprehensive study on melanocytic tissue samples investigating the expression of 18 chemokine receptors at the mRNA level by real-time polymerase chain reaction, using a semiquantitative approach, and of 3 chemokine receptors (CXCR6, CCR9, and XCR1) at the protein level. We report on the de novo expression of CXCR6 in primary melanomas and melanoma metastases, but absence in melanoma cell lines and congenital nevi.