title: Immunohistochemical differentiation of inflammatory myopathies.
abstract: BACKGROUND
  Idiopathic inflammatory myopathies are a heterogeneous group of acquired muscle disorders with considerable overlap in the histological features, making histological diagnosis difficult at times.
  
  
  OBJECTIVE
  To determine the immunohistochemical profile of clinically suspected cases of inflammatory myopathies, using monoclonal antibodies to HLA-1 and membrane attack complex (MAC), and to correlate the clinical, serological, and electromyographic profile and the histopathological picture, with the immunohistochemical profile.
  
  
  METHODS
  This was a retrospective study analyzing the clinical and histopathological features in muscle of clinically suspected cases of inflammatory myopathy and correlating it to their HLA-1 and MAC immunostaining profiles.
  
  
  METHODS
  The study subjects included 33 cases with suspected inflammatory myopathy and 59 with non-inflammatory muscle disease, as controls. Clinical data, electromyographic findings, serological profile, and details of therapy were obtained from patient records.
  
  
  METHODS
  Student 'T' test, Pearson's Chi square test, and Kappa statistics were used appropriately.
  
  
  RESULTS
  Although HLA-1 and MAC immunostaining did not help to differentiate the individual subtypes of inflammatory myopathy, when either HLA-1 or MAC was positive, inflammatory myopathy could be ruled in with 86.5% certainty and when both HLA-1 and MAC were negative, it could be ruled out with 95% certainty.
  
  
  CONCLUSIONS
  A combination of clinical presentation, serological profile, electromyographic and histopathological features, together with the immunoprofile for HLA-1 and MAC, contribute toward making a diagnosis of inflammatory myopathy.
authors: Department of Neurological Sciences and Pathology, Christian Medical College, Vellore, India.
authors: Jayalakshmi B
authors: JB
authors: Panicker
authors: Geeta
authors: G
authors: Chacko
authors: Anil Kumar B
authors: AK
authors: Patil
authors: Mathew
authors: M
authors: Alexander
authors: Jayaprakash
authors: J
authors: Muliyil
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015938:Complement Membrane Attack Complex / Q000378:metabolism*; D003882:Dermatomyositis / Q000378:metabolism / Q000473:pathology; D004576:Electromyography; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D009220:Myositis / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D017285:Polymyositis / Q000378:metabolism / Q000473:pathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015938:Complement Membrane Attack Complex; D015395:Histocompatibility Antigens Class I