title: [A study of T cell recombination excision circles levels in peripheral blood mononuclear cells of systemic lupus erythematosus patients].
abstract: OBJECTIVE
  To compare the T cell receptor recombination excision cycle (TREC) levels in peripheral blood mononuclear cells (PBMC) of systemic lupus erythematosus (SLE) patients with normal age- and gender- matched controls. To investigate the correlations between TREC levels of SLE patients and their clinical features.
  
  
  METHODS
  We studied TREC levels in peripheral blood mononuclear cells (PBMC) of 21 SLE patients and 22 normal age- and sex-matched controls. TREC concentration was determined by real-time quantitative polymerase chain reaction (real-time qPCR) as the number of TREC copies/1000 PBMCs. The clinical features of the SLE patients such as systemic lupus erythematosus disease activity index (SLEDAI), ESR, C reaction protein (CRP), ANA, anti-dsDNA and complement levels and organ involvement were recorded and assessed.
  
  
  RESULTS
  SLE patients had lower TREC levels [(9.6±7.5) copies/1000 PBMC] than controls [(16.1±11.1) copies/1000 PBMC, P=0.033]. There was an inverse correlation between age and TREC levels in controls (r=-0.614, P=0.002) but not in SLE patients. There was an inverse correlation between SLEDAI and TREC levels in SLE patients (r=-0.656, P=0.001) and TREC levels seemed to have relations to skin lesions (r=-0.620, P=0.003). No other clinical association was observed between TREC levels and clinical and laboratory SLE manifestations.
  
  
  CONCLUSIONS
  SLE patients had lower TREC levels than normal controls and there is a tendency that TREC level is reversely correlated with disease activity. The decrease PBMC TREC level is indicative of a low proportion of recent thymic emigrant (RTE) in SLE and could be caused by decreased RTE output and/or by increased peripheral T cell proliferation in this disease. The under-representation of RTE in the peripheral T cell pool may play a role in the immune tolerance abnormalities observed in SLE.
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing 100032, China.
authors.forename: Zhen-yan
authors.initials: ZY
authors.lastname: Du
authors.forename: Xiao-mei
authors.initials: XM
authors.lastname: Leng
authors.forename: Fu-lin
authors.initials: FL
authors.lastname: Tang
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D055815:Young Adult
chemical_list: D011948:Receptors, Antigen, T-Cell