Substance P binding in normal neonatal foreskin

Modulation of substance P and somatostatin receptors in cutaneous lymphocytic inflammatory and tumoral infiltrates

BACKGROUND

The expression of receptors for neuropeptides in the skin is modified in skin diseases.

OBJECTIVE

We studied the cutaneous expression of substance P (SP) and somatostatin (SOM) receptors (SPR and SSTR, respectively) in skin affected by cutaneous inflammatory or tumoral T-cell infiltrates because these two neuropeptides are the ones most involved in inflammation.

METHODS

We revealed expression of these receptors using a binding in situ technique that gave highly specific results. Skin biopsies were incubated with biotinylated neuropeptides (SP or SOM).

RESULTS

In normal skin, SSTR were observed on blood vessels, smooth muscle fibres and sweat glands. SSTR expression was modified only when expressed by keratinocytes in Ofuji papuloerythroderma and by plasmocytes in plasmocytoma. SPR distribution was not modified in subjects with atopic dermatitis or lupus. The expression of SPR in the epidermis was diminished in Ofuji papuloerythroderma and parapsoriasis and absent in mycosis fungoides.

CONCLUSIONS

These results suggest that malignant lymphocytic infiltrates can inhibit SPR expression on keratinocytes.

Effect of UVB 311 nm irradiation on normal human skin

Ultraviolet radiation B (UVB) on the skin induces erythema, inflammation and modifications of the immune system. These changes have been reported after excessive short-term or long-term exposure to broad spectrum UVB. In this study, we examined the effects of local repetitive UVB irradiation of 311 nm wavelength on the skin of seven young volunteers. Skin biopsies were taken before and after UVB irradiation, and we immunohistochemically analyzed the expression of CD1a and HLA-DR antigens of Langerhans cells (LC), the possible infiltration of dermis/epidermis by CD11b macrophages, the modifications or the induction of intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) involved in the binding of leukocytes to the endothelial surface and the development of perivascular infiltrates of LFA-1+ mononuclear cells. We also determined the expression of substance P receptors (SPR) using biotinylated substance P (SPB). Exposure of UVB 311 nm induced a drastic reduction of CD1a+ cells and a moderate increase of HLA-DR+ dendritic cells in the epidermis without infiltration by CD11b macrophages. An increase of the binding of SPB to upper layer epidermal cells was noted in five of seven biopsies. In the dermis, vessel-associated ICAM-1 expression increased and an induction of E-selectin occurred on nearly 20 to 40% of endothelial cells, but VCAM-1 expression remained undetectable. The percentage of LFA-1+ cells did not change significantly after irradiation. These observations may be compatible with a selective role of UVB 311 nm on the skin immune response.