title: Frequency of naturally-occurring regulatory T cells is reduced in patients with ST-segment elevation myocardial infarction.
abstract: BACKGROUND
  Naturally-occurring regulatory T cells (Treg) constitute a mature T-cell population characterized phenotypically by co-expression of CD4 and CD25(high) surface molecules. We investigated here the frequency of circulating Treg in patients presenting with STEMI in comparison with subjects without coronary artery disease (CAD). The effect of primary percutaneous coronary intervention (PCI) with implantation of a bare (BS) or paclitaxel-eluting stent (PES) on peripheral Treg distribution was also examined.
  
  
  METHODS
  Peripheral blood mononuclear cells were isolated from 30 consecutive patients presenting with STEMI and from 30 age-matched control subjects with angiographically normal coronary arteries. Treg were detected by flow cytometry according to their characteristic CD4+ CD25(high) membrane phenotype, and their frequency was assessed before PCI and at 48 h and at 6 days after PCI. CD27 expression identifying a highly suppressive Treg subset was also analysed.
  
  
  RESULTS
  The percentages of both (CD27+)Treg and (CD27-)Treg were significantly lower in patients with STEMI in comparison with controls. In addition, the (CD27+)Treg/(CD27-)Treg ratio was skewed toward the CD27- population. The frequency of both Treg subsets significantly increased 48 h after either BS or PES implantation, remaining elevated for up to at least 6 days after PCI.
  
  
  CONCLUSIONS
  Our data suggest that the percentage of circulating Treg is significantly reduced in patients with STEMI, suggesting that this immunosuppressive T-cell subset is compartmentalized within the acutely ischemic myocardium to limit the ongoing inflammation associated with this condition, and that coronary revascularization is associated with partial reconstitution of peripheral Treg pool.
authors.affiliation: Department of Cardiovascular and Respiratory Sciences, La Sapienza University, Policlinico Umberto I, Viale del Policlinico, 155, 00161-Rome, Italy. rino.sardella@uniroma1.it
authors.forename: Gennaro
authors.initials: G
authors.lastname: Sardella
authors.forename: Leonardo
authors.initials: L
authors.lastname: De Luca
authors.forename: Vittorio
authors.initials: V
authors.lastname: Francavilla
authors.forename: Daniele
authors.initials: D
authors.lastname: Accapezzato
authors.forename: Massimo
authors.initials: M
authors.lastname: Mancone
authors.forename: Maria Isabella
authors.initials: MI
authors.lastname: Sirinian
authors.forename: Francesco
authors.initials: F
authors.lastname: Fedele
authors.forename: Marino
authors.initials: M
authors.lastname: Paroli
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D004562:Electrocardiography; D005434:Flow Cytometry; D006801:Humans; D007249:Inflammation / Q000276:immunology; D009203:Myocardial Infarction / Q000276:immunology*; D015607:Stents; D016176:T-Lymphocyte Subsets / Q000166:cytology; D050378:T-Lymphocytes, Regulatory / Q000166:cytology*