Abstract: Objective To quantify the intraepidermal nerve fibers and to observe their contacts with Langerhans cells in the lesional skin of neurodermatitis.Methods Skin specimens were resected from 24 patients with neurodermatitis and 24 normal human controls.A labeled-streptavidin-biotin(LAB-SA)method was used to study the expression and counts of nerve fibers in the specimens.Double labeled immunofluorescency and confocal laser scanning microscopy were employed to observe the contact of nerve fibers with Langerhans cells.The mRNA expression of NGF was measured by real time PCR in the specimens.Results The nerve fibers were significantly longer in lesions of neurodermatitis than those in normal controls (337.33±91.94μm vs 206.60±64.21μm,t=5.71,P<0.001)and those in the skin around the lesions (337.33±91.94μm vs 210.74±70.69μm,t=6.90,P<0.001).The percentage of intraepidermal nerve fibers contacting with Langerhans cells was significantly higher in lesions of neurodermatitis than that in normal control(56.14±10.12)% vs(22.49±5.93)%,X²=46.11,P<0.001)and that in the skin around the lesions(56.14±10.12)% vs(23.93±5.97)%,X²=43.91,P<0.001).The mRNA expression of nerve growth factor significantly increased in the lesional skin than in the skin around the lesions and in normal controls(2761.5±178.5 vs 1859.5±157.9,t=3.25,P<0.01;2761.5±178.5 vs 1003.5±102.1,t= 3.67,P<0.01).Conclusion It is indicated that nerve fibers hyperplasy in the lesions of lichen simplex chronicu,which may be related to the high level of nerve growth factor in the area.

Key words: Neurodermatitis, Nerve fibers, Langerhans cells, Nerve growth factor