Calcitonin gene-related peptide in Langerhans cells in psoriatic plaque lesions

Objective To study the mechanism of stress exacerbating psoriasis and the i nvolvement effect of neuropeptides in psoriatic pathogenesis, we investigat ed the expression and secretion of calcitonin gene-related peptide (CGRP) i n psoriatic lesions, then identified the target cells of CGRP, the characte rs of CGRP positive dendrite cells and the source of CGRP in psoriatic plaq ue lesions. Methods Specific radioimmunoassay (RIA) and immunohistochemistry staining m ethods were used to determine CGRP secretive content and the target cells o f CGRP in psoriatic plaque lesion tissue of vulgaris psoriasis. Double immu nofluorenscence staining was done on psoriatic plaque lesion sections by fi rst using rabbit anti-human CGRP antibody and mouse antihuman CD1a antibody , second using PE-conjugated anti-mouse immunoglobulin and FITC-conjugated anti-rabbit immunoglobulin. Confocal laser microscope showed the psoriatic lesion sections. Then both digoxigenin labelled anti-sense and sense RNA pr obe of CGRP were synthesized to make sure the source of CGRP on the dendrit e cells. The psoriatic lesion sections were studied by in situ hybridizatio n. Results The content of CGRP in vulgaris psoriatic plaque lesions was higher than that of normal controls (P < 0.01). CGRP was also found on the dermal microvascular endothelial cells and the epidermal dendrite cells in psoria tic plague lesions. Further study showed that CGRP existed on the surface o f epidermal CD1a + Langerhans cell in psoriatic plaque lesion. The CGRP mRN A expressed around the nucleus of the Langerhans cells in psoriatic lesion. Conclusions The pathogenesis of psoriatic plaque lesions was closely relate d to the overexpression of neuropeptide CGRP. The CGRP contacted with the d ermal microvascular endothelial cells and epidermal dendrite cells in psori atic plaque lesion. The CGRP positive epidermal dendrite cell was CD1a + La ngerhans cell. The Langerhans cell itself expressed CGRP mRNA.