Expression of membrane attack complex in common idiopathic inflammatory myopathy / 中华神经科杂志

ABSTRACT

Objective To analyze membrane attack complex (MAC) expression in different types of idiopathic inflammtory myopathy (IIM).Methods We enrolled 57 cases of dermatomyositis (DM) , 37 cases of polymyositis (PM) ,9 cases of sporadic inclusion body myositis (sIBM) and 15 cases of autoimmune necrotizing myopathy with anti-signal recognition particle antibodies (SRP-ANM) in Department of Neurology at Peking University First Hospital from 2011 to 2014, and used x2 test or Fisher exact test to analyze MAC expression in muscle fibers and endomysial capillaries respectively.Results The total MAC expression in DM, PM, sIBM and SRP-ANM was 75.4％ (43/57), 86.5％ (32/37), 4/9 and 13/15 respectively.The MAC expression in muscle fibers was 50.9％ (29/57), 81.1％ (30/37) , 3/9 and 13/15 respectively.The MAC expression in endomysial capillaries was 49.1％ (28/57) , 24.3％ (9/37) , 1/9 and 6/15 respectively.The MAC expression in muscle fibers and endomysial capillaries of sIBM was less than other types of IIM.The MAC expression in muscle fibers of PM and SRP-ANM was higher than DM and sIBM, but there was no statistically significant difference between PM and SRP-ANM.The MAC expression in endomysial capillaries of DM and SRP-ANM was higher than PM and sIBM, while there was no statistically significant difference between DM and SRP-ANM (x2 =0.397, P =0.574).The MAC expression in four types of IIM had regional distribution, of which 11.6％ (5/43) of DM showed bundle distribution.Conclusion There are differences in the damage of MAC in various types of IIM, the damage of MAC in SRP-ANM indicated the pattern of both DM and PM.