title: Phenotypes and clinical significance of circulating CD4(+)CD25(+) regulatory T cells (Tregs) in patients with acute-on-chronic liver failure (ACLF).
abstract: BACKGROUND
  CD4(+)CD25(+) regulatory T cells (Tregs) play an important role in maintaining immunological tolerance to self and foreign antigens. T cell receptors (TCR) reflect the composition and function of T cells. It is not universally agreed that there is a relationship between CD4(+)CD25(+) Treg frequency and the severity of acute-on-chronic liver failure (ACLF). The repertoire of TCR beta chain variable (TCRBV) regions of peripheral Tregs in ACLF patients is not well understood.
  
  
  METHODS
  Human PBMCs were separated and sorted into CD4(+)CD25(+) Treg subsets using density gradient centrifugation and magnetic activated cell sorting (MACS). The CD4(+)CD25(high) Treg frequency in peripheral blood of ACLF and chronic hepatitis B (CHB) patients was measured by flow cytometry. The molecular profiles of TCRBV CDR3 were determined using gene melting spectral pattern (GMSP) analysis. TCRBV gene families were cloned and sequenced when the GMSP profiles showed a single-peak.
  
  
  RESULTS
  CD4(+)CD25(high) Treg prevalence in peripheral blood of ACLF patients is increased significantly compared to healthy donors (HDs) (P < 0.01) and CHB patients (P < 0.01). The prevalence of CD4(+)CD25(high) Tregs in ACLF or CHB patients is positively correlated with HBV DNA load. The TCRBV11, BV13.1, BV18, BV20 are the most prevalent TCRBV in CD4(+)CD25(+) Tregs in ACLF and CHB patients. In addition, the CDR3 motifs were relatively conserved in these four TCRBV gene families.
  
  
  CONCLUSIONS
  The CD4(+)CD25(high) Tregs prevalence in peripheral blood is indicative of disease severity in ACLF or CHB patients. The relatively conserved TCRBV20 CDR3 motif "TGTGHSPLH" and TCRBV11 CDR3 motif "VYNEQ" may be used in helping diagnosis and treat patients with ACLF.
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.
authors.forename: Jiezuan
authors.initials: J
authors.lastname: Yang
authors.forename: Ping
authors.initials: P
authors.lastname: Yi
authors.forename: Li
authors.initials: L
authors.lastname: Wei
authors.forename: Zherong
authors.initials: Z
authors.lastname: Xu
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Chen
authors.forename: Lingling
authors.initials: L
authors.lastname: Tang
authors.forename: Lanjuan
authors.initials: L
authors.lastname: Li
mesh_terms: D000328:Adult; D015704:CD4 Antigens / Q000276:immunology*; D002498:Centrifugation; D058625:End Stage Liver Disease / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit