Ultrastructure of Langerhans cell in pityriasis rosea lesions

Purpose To investigate the effect of Langerhans Cell(LC) during the occurrence and development of pityriasis rosea(PR). Methods Thirty-one PR biopsies were selected from PR patients diagnosed by clinic and histopathology.Seventeen healthy skins were selected as normal controls.Cluster of differentiation 1a(CD1a) expression was detected by immunohistochemical method.Eight PR lesions and 4 normal trunk skins were detected by transmission electronic microscope. Results Amount of LC and the length of its dendrite in PR lesions was markedly increased compared with controls(P0.05).In LC of PR lesions,the Birbeck granules increased and rough endoplasmic reticulum dilated,mitochondria and rough endoplasmic reticulum decreased.And mitochondria edema,disappearance of mitochondria ridge can also be found. Conclusions LC plays an important role in the occurrence of PR.As the main antigen present cells(APC) in skin,LC participates actively in catching,processing,presenting antigens then mediates the occurrence of delayed allergy which probably leads the occurrence of PR lesions and promotes the development of the disease.Furthermore,the LC was injured itself at the same time.