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 mod ified in skin diseases. Objective We studied the cutaneous expression of substance P (SP) and somat ostatin (SOM) receptors (SPR and SSTR, respectively) in skin affected by cu taneous inflammatory or tumoral T-cell infiltrates because these two neurop eptides are the ones most involved in inflammation. Methods We revealed expression of these receptors using a binding in situ t echnique that gave highly specific results. Skin biopsies were incubated wi th 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 b y keratinocytes in Ofuji papuloerythroderma and by plasmocytes in plasmocyt oma. SPR distribution was not modified in subjects with atopic dermatitis o r lupus. The expression of SPR in the epidermis was diminished in Ofuji pap uloerythroderma and parapsoriasis and absent in mycosis fungoides. Conclusions These results suggest that malignant lymphocytic infiltrates ca n inhibit SPR expression on keratinocytes.