The Experimental And Clinical Study On Diagnosis And Therapy Of Idiopathic Inflammatory Myopathy

Objectives1 To investigate the methods of inducing experimental autoimmune myositis animal model.2 To assess the clinical effects of infliximab(anti-TNF-a monoclonal antibody) in experimental autoimmune myositis.3 To investigate the diagnostic value of MHC-I expression in PM/DM.4 To evaluate the therapeutic effects of IVIg in polymyositis;Methods1 Inducing experimental autoimmune myositis animal model with partly purified rabbit muscle myosin (6g/L) or pure myosin (1mg/L ) mixed with CFA injected subcutaneously in guinea pigs, associated with bacillus pertussis(4.0×10¹⁰) injected intraperitoneally, and comparing the two models in clinical symptoms and pathology.2 To treat EAM animals with infliximab(0.125ml/time/week), dexamethasone(lmg/d) and normal saline(lml/W) injected intraperitoneally and evaluate the effects of infliximab according to the clinical symptoms and pathological examination.3 To investigate the diagnostic value of MHC-I expression in PM/DM by analyzing the results of clinical and pathological findings and theimmunohistochemical findings of MHC-I expression in 54 cases from Sep, 2005 to Apr, 2006;4 To analyze retrospectively the clinical findings of 62 patients of PM and investigate the effects of IVIg in PM.Results1 The clinical findings and pathologic changes in guinea pigs induced by partly purified muscle myosin of rabbit or pure myosin mixed with CFA injected subcutaneously were similar to the human's in idiopathic inflammatory myopathy;Compared with the models induced by partly purified muscle myosin of rabbit, the mortality of the models induced by pure myosin was lower and achievement ratio was higher;The changes in pathology was typical.2 Dexamethasone and infliximab were effective in the treatment of EAM according to the scores of clinical symptoms and pathology.3 Among the 16 patients with IIM, 63 percent patients showed inflammatory infiltration, 94 percent showed MHC-I expression;Among 19 patients with progressive muscular dystrophy, 9 percent patients showed inflammatory infiltration, 11 percent showed MHC-I expression. The other 19 patients showed no inflammatory infiltration and MHC-I expression.4 (l)The creatine kinase values decreased and MRC increased markedly in all the patients after treatment. The t test showed the differences of CK values and MRC after treatment were significant statistically. (2) There was no significant difference in decreased CK value after treatment among all the groups. The MRC increase in group IVIg was higher than group NonlVIg, and group B was higher than group C and D. There was no significant differences between group Methylprednisone and Non-methylprednisone, among group A, C and D. (3) There was no significant difference in effective ratio among group A, B, C and D by (exact propability). But the difference between group B and D was significant by yl test (half exact propability), /><0.05;(4) There was no synergistic effect between the treatment of infliximab and methylprednisone by F test of factorial design. IVIg may increaseMRC in a short time(23 days), the difference was significant statistically (Z'<0.05). But methylprednisone did not attain the difference.Conclusion1 The animal model induced by pure myosin showed lower mortality , higher achievement ratio, and typical pathologic changes, so it was a ideal animal model to investigate IIM.2 Infliximab was effective in the treatment of EAM.3 MHC-I expression serving as a diagnostic index of PM/DM was an appropriate index because of the ideal sensitivity, specificity, and negative likelihood ratio.4 IVIg combined with prednison was the optimization method.