title: Phenotypic patterns of mononuclear cells in dilated cardiomyopathy.
abstract: BACKGROUND
  Immunological factors in the pathogenesis of idiopathic dilated cardiomyopathy (IDC) were suggested previously on the basis of the demonstration of mononuclear cell infiltrates and autoantibodies against the myocardium. The present study investigated whether tissue leukocyte subpopulations isolated from hearts with IDC (n = 6) differ in phenotype from those of tissues without IDC (n = 7).
  
  
  RESULTS
  Leukocytes were quantified as reactive cells per square millimeter in perivascular, interstitial, and parenchymal tissue sections. Freshly isolated heart-tissue T cells and peripheral-blood T cells from the same patients were analyzed by triple staining and flow cytometry to identify T-cell subpopulations as well as their states of differentiation (expression of CD45RA and Leu-8 versus CD45RO) and activation (IL-2R, IL-7R, very late antigen-1, HLA-DR). All types of infiltrating cells (T cells, B cells, macrophages, granulocytes) are increased in hearts with IDC compared with normal hearts, but only CD8+ T cells and macrophages are increased relative to the other leukocyte subpopulations. CD45RO+/CD45RA-/Leu-8- cells constitute the majority of heart-tissue T cells in both normal hearts and hearts with IDC. Strikingly, hearts with IDC are infiltrated by eightfold greater numbers of perivascularly located IL-2R(+)- (26% of all T cells) and CD45RO(+)-activated memory T cells; moreover, in contrast to normal heart, approximately 40% of both CD4+ and CD8+ heart-tissue T cells express activation markers.
  
  
  CONCLUSIONS
  Both normal hearts and hearts with IDC are populated by leukocytes. The quantitative increase in IDC, associated with a dramatically altered activation status of heart-tissue T cells, suggests a direct role of infiltrating leukocytes in the pathogenesis of IDC.
authors.affiliation: Second Department of Surgery, University of Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Holzinger
authors.forename: A
authors.initials: A
authors.lastname: Schöllhammer
authors.forename: M
authors.initials: M
authors.lastname: Imhof
authors.forename: C
authors.initials: C
authors.lastname: Reinwald
authors.forename: G
authors.initials: G
authors.lastname: Kramer
authors.forename: A
authors.initials: A
authors.lastname: Zuckermann
authors.forename: E
authors.initials: E
authors.lastname: Wolner
authors.forename: G
authors.initials: G
authors.lastname: Steiner
mesh_terms: D002311:Cardiomyopathy, Dilated / Q000097:blood / Q000276:immunology* / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D005434:Flow Cytometry; D006333:Heart Failure / Q000097:blood / Q000276:immunology / Q000473:pathology; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D007124:Immunoenzyme Techniques; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology