Immunopathologic Study Of Idiopathic Inflammatory Myopathies

Objective: To study the expression of major histocompatibility complex (MHC) on muscle biopsy specimens of idiopathic inflammatory myopathies(IIM) and analyze the composition and types of infiltrating monouclear cells, assess diagnostic value of MHC/T cell expression in IIM. To evaluate the expression of apoptosis associated proteins, such as Fas, FasL, Bcl-2, FLIP, survivin and costimulatory molecule-OX40 in IIM, and investigate their immunopathologic roles in IIM.Method: 33 patients with IIM (12 polymyositis and 21 dermatomyositis) admittedto Sino-Japan Friend Hospital from 1986 to 2005 were selected for this study. All the patients fulfilled the diagnostic criteria for IIM according to Bohan&Peter criteria. 20 healthy subjects without clinical and histological evidence of IIM were collected as control groups. Immunohitochemical staining was applied to identify expression of HLA-A/B/C, HLA-DR, CD3, CD20, CD4, CD8, CD45RA, CD45RO, Fas, FasL, Bcl-2, FLIP, survivin and OX40 on muscle biopsy specimens in PM/DM patients and healthy controls. A qualitative analysis of each specimen was followed by a quantitative assessment. The relationship between the immunostaining findings and the clinical features of patients with PM/DM was analyzed.Result: HLA-A/B/C over-expression was evident on muscle fibers in 11 out of 12PM patients(91.6%), 19 out of 21 DM patients(90.4%) and 3 out of 20 healthy controls(15%), respectively. The positive expression of HLA-DR in PM, DM groups and healthy controls were 75%, 80.9%, 20%, respectively. The expression of HLA-A/B/C and HLA-DR in PM and DM patients were significantly increased than that in healthy controls (P<0.05), but no significant different between PM and DM (P>0.05). No significant correlations were found between the over-expression of HLA-A/B/C and HLA-DR and the existence of inflammatory infiltration, muscle damage and clinical features in PM/DM...