Bcl-2, p53 and c-myc expression in juvenile dermatomyositis

OBJECTIVE: To investigate p53, bcl-2 and c-myc expression in muscle biopsies from children affected with juvenile dermatomyositis (JDM) and to verify a possible dysregulation of programmed cell death in this autoimmune disease. METHODS: Ten muscle biopsies of children affected with JDM were formalin fixed and paraffin embedded. After haematoxylin and eosin staining, immunohistochemistry was performed employing monoclonal antibodies, anti-p53, anti-bcl-2 and anti-myc. Two normal muscle biopsies were studied as controls. RESULTS: In the biopsies of JDM, two different patterns of myofibers damage were observed: the first, with zones characterised by necrosis; and the second, with zones where an apoptotic process was dominant. Immunoreactivity for bcl-2 was positive in 8 out of 10 biopsies. P53 and c-myc expression were not present in any case. No relationship between the degree of bcl-2 immunostaining and the disease course or outcome was observed. CONCLUSIONS: The over-expression of bcl-2 protein in JDM may suggest a dysregulation of apoptosis in myofibers. Further studies are required in order to better understand the role of our data in the pathogenetic pathways of the disease.