[Expression of apoptosis of the skin lesion and muscle from patients with dermatomyositis].

OBJECTIVE: This study inquired into the relationship between the influence of corticosteroid and the expression of apoptosis, Fas and Bcl-2 in muscle from patients with dermatomyositis (DM). METHODS: Corticosteroid was given to group A (10 DM cases) but not given to group B (12 DM cases). RESULTS: Apoptotic cells were detected in situ by terminal deoxynucleotidyl transferase-mediated-dUTP nick end labeling (TUNEL). Fas and Bcl-2 expressions was determined with the use of immunohistochemical staining in DM. The results showed that more expression of apoptosis in keratinocytes, muscle cells and lymphocytes were observed in group A. The apoptotic index (AI) of muscle cells and that of lymphocytes were more marked in group A than in group B (P < 0.05). Less apoptosis cells were observed in two weeks of treatment, and no correlation was found between apoptosis and the lesion of skin and muscle. CONCLUSION: The authors suggest that corticosteroid may play a role in inducing the apoptosis of keratinocytes, muscle cells and lymphocytes, which may be one of the therapeutic mechanisms of corticosteroid. The length of administering corticosteroid to the patients seems related to apoptosis.