Comparative Analysis Of Idiopathic Inflammatory Myopathy Subtype Diagnosis Criteria

Objective：Idiopathic inflammatory myopathy (IIM) is a heterogeneousgroup of acquired autoimmune muscle disorders. Bohan and Peter criteria(B/P criteria) are the most widely used in IIM classification diagnosis, thelatest standards is ENMC standards which wae put forward by the2004European neuromuscular disease center. Collect the clinical、 laboratory andpathology data of86patients who were initially diagnosed IIM, and makediagnostic analysis. To estimate the accuracy of diagnosing dermatomyositis(DM) and polymyositis (PM) by B/P criteria and ENMC criteria.Methods：We had collected retrospectively the clinical, laboratory andpathological data of86patients who were initially diagnosed idiopathicinflammatory myopathy from2004.9to2012.11in the department ofneuromuscular disease of the Third Hospital of Hebei Medical University. Allhospitalized patients had complete medical records, serum muscle enzyme,erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), ENApolypeptide antibody spectrum and electromyography (EMG) test, somepatients do nuclear magnetic resonance (MRI) of lower limbs. We undertookopen biceps brachii、quadriceps femoris or diseased region biopsy in86patiens after anesthesia and they all signed the consents. All speciments werevertically fixed with tragacanth, sufficiently cooled down in isopentane orliquid nitrogen, cut into slices of7um in thickness using constant cold slicer.The frozen tissues were stained with haematoxylin-eosin（HE）, modifiedgomori’s trichrome（MGT）, nicotinanide adenine dinucleotide（NADH-TR）,succinate dehydrogenase （SDH）, cytochrome coxidase （COX）, acidphosphataseand（Acid）, periodic acid schiff （PAS）, oil red O（Oil）,adenosine triphosphatase（ATPase）and were received pathological analysisunder optical microscope. Some frozen tissues were stained with immunohistochemical stain for MHC-I、CD4、CD8、dysferlin monocloneantibody. These patients were diagnosed according to B/P criteria and ENMCcriteria, and the similarities and differences of diagnosing DM and PM werecompared through the two sets of criteria. Analysis is discussed combinedwith the domestic and foreign literature.Results：1General clinical data:86patients who were initially diagnosed idiopathic inflammatorymyopathy:26males and60females. Mean age (40±2) year; The averagecourse (11±2) months. Proximal limb weakness mainly accounted for77cases(90%), and/or distal limb weakness19cases (22%), neck muscle weakness42cases (49%), swallowing hard12cases (14%), breathing hard8cases (9%),rash37cases (43%). Patients was diagnose by B/P criteria and ENMC criteria,the clinical data of2groups (B/P criteria group: a；ENMC criteria group: b)refer Table4.2Laboratory examination data:Serum crestine kinase (CK) increased in68/86cases (79%), ESRincreased in57/86cases (66%), CRP increased in24/56cases (43%);antinuclear antibody positive in15/49cases (31%), anti-SSA antibodypositive in4/49cases (8%), anti-SSB antibody positive in2/49cases (4%),anti Jo-1antibody positive in1/49cases (2%). EMG examination in78patients: myopanic chang or fibrillation potentials and positive sharp waves in67cases (86%), myopanic chang combined peripheral nerve abnormality in3cases(4%), normal in8cases (10%). Lower limb MRI in7cases:T1-Weighted signal, T2WI and STIR sequence focal high signal in3cases;T1WI, T2WI slice high signal, STIR sequence low signal, muscle widenedgap in4cases. Patients was diagnose by B/P criteria and ENMC criteria, thelaboratory data of2groups (B/P criteria group: a；ENMC criteria group: b)refer Table5. The CK of PM group was significantly increased than DMgroup were diagnosed by ENMC criteria (P＜0.05）, the ESR/CRP of PMgroup was increased than LGMD2B group, the different is statistically significant (P＜0.05）.3Pathological analysis of skeletal muscle biopsies:Histochemistry pathology finds of86patients:83cases had variousdegrees of muscle fiber degenerating、necrosis、regeneration, and many fibersare degenerating or necrosis in21cases, connective tissue elements areslightly/moderate/severe increased in70cases,28cases had atrophy fibers infascicle,11cases showed "punch-out vacuoles" muscle fibers, inflammatorycells infiltrated in perimysium/perivascular in34cases; inflammatory cellsinfiltrated in endomysial/perivascular in23cases, surrounding and invadingnon-necrotic muscle fibres in9cases.9cases had rimmed vacuoles. Patientswas diagnose by B/P criteria and ENMC criteria, the pathological finding of2groups (B/P criteria group:a；ENMC criteria group:b) refer Table6.20cases were treated with immunohistochemical stain of anti-MHC-I,CD4, CD8monoclone antibody: MHC-I muscle fiber of varying degrees ofpositive expression on perifascicular fibers and perimysium in8cases; MHC-Iextensively expressed on sarcolemma and inflammatory cells infiltration areain8cases, and another4cases expressed negatively. CD4+T cells expressedon perifascicular fibers and perimysium in10cases, CD8+T cellsexpressed on endomysial in5cases,1case of them slightly expressed onperimysium; CD4+T cells expressed negatively in3cases with rimmedvacuoles, CD8+T cells expressed slightly in1case of them.The molecular pathology by immunohistochemical stain of anti-dysferlinmonoclone antibody in27cases showed that dysferlin protein positivelyexpress in16cases, while fully/partially deficient in11cases are diagnosedwith LGMD2B.4Classification diagnosis and comparison:37DM and49PM were diagnosed using B/P criteria.46DM and14PMwere diagnosed using ENMC criteria, and the rest were:1case of eosinophilicmyositis,9cases of sporadic inclusion body myositis (sIBM),11cases oflimb-girdle muscular dystrophy type2B (LGMD2B),5patients can’t beconfirmed. Agreement was showed in subtype categories between the two sets of criteria using the kappa test. Agreement for DM was very good (κ=0.79),and for PM was poor (κ=0.26).Conclusion：1At present, pathological analysis has not been popular in our country. Biopsy of muscle is essential for IIM diagnosis, should be actively popularized.2B/P criteria according to the presence of rash distinguish between PM and DM, it will miss possible dermatomyositis sine dermatitis, and can’t distinguish between PM and sIBM, easily misdiagnosed musculardystrophy as PM.3ENMC criteria contains MRI、 MSAs、 Immunohistochemicalpathology, and detailings clinical、laboratory、pathological standard andexclusion standard, defines NSM and IMNM diagnostic criteria, so ENMCcriteria is better in clinical practice.4ENMC criteria is superior to B/P criteria in diagnostic accuracy,it should be actively application to raise the level of clinical diagnosisand treatment.