Eosinophil cationic protein- and eosinophil-derived neurotoxin/eosinophil protein X-immunoreactive eosinophils in prurigo nodularis

It is known that eosinophils are actively involved in allergy and inflammat ion. The granular components of eosinophils, eosinophil cationic protein (E CP) and eosinophil-derived neurotoxin/eosinophil protein X (EDN/EPX), play an important role in such allergic and inflammatory processes. Prurigo nodu laris is a chronic inflammatory skill disease with obvious cutaneous nervou s involvement, To detect ECP and EDN/ EPX expression in the eosinophils and their relation to nerve fibres in prurigo nodularis, ECP and EDN/EPX singl e-labelling immunofluorescence, and ECP and PGP 9.5 double-labelling immuno fluorescence, were performed. In prurigo nodularis lesional skin, the ECP- and EDN/EPX-containing cells, which were mainly distributed in the upper de rmis, were significantly increased in number compared to their numbers in u ninvolved and normal skin, The immunoreactivity of ECP and EDN/EPX in pruri go lesional skin was stronger than in uninvolved skin or control skin. The PGP 9.5-immunoreactive nerves were also increased in number in the areas wh ere there were increased eosinophils. The nerves were in close proximity to eosinophils, and occasionally even seemed to be in contact. The present re sults indicate that the cutaneous nerves and the ECP- and EDN/EPX-containin g eosinophils are possibly involved in the pathogenesis of the disease. The close relationship of nerves and eosinophils indicates that the cutaneous nerves may influence eosinophil function in the chronic inflammatory states of prurigo nodularis, ECP and EDN/EPX could thus be released to the local tissue and modulate the inflammation of the prurigo nodularis lesion.