title: Relationship of CD4+CD25+ regulatory T cells to immune status in HIV-infected patients.
abstract: OBJECTIVE
  To determine whether the frequencies of CD4+CD25+ regulatory T cells (T Reg) were related to immune status in HIV-infected patients.
  
  
  METHODS
  Peripheral blood CD4 T-cell populations were examined for T-helper 1 cells (Th1), T-helper 2 cells (Th2), and T Reg by intracellular staining for interferon (IFN)-gamma and interleukin (IL)-4, and surface staining for CD25, respectively. The immunoregulatory properties of T Reg were assessed by measurement of the inhibitory effects of isolated CD4+CD25+ T Reg on CD4+CD25- T-cell proliferation.
  
  
  RESULTS
  Isolated CD4+CD25+ T Reg from both HIV-infected patients and healthy controls strongly expressed CD45RO, HLA-DR, and FoxP3. HIV-infected patients with detectable plasma HIV-1 RNA showed a statistically significant increase in CD4+CD25high T Reg frequencies (P < 0.05) compared to healthy controls, with T Reg frequency inversely proportional to CD4 T-cell count (P < 0.01). However, in HIV-infected patients with undetectable plasma HIV-1 RNA, CD4+CD25high T Reg frequencies were not increased and were not related to CD4 T-cell counts. In both HIV-infected patient groups, T Reg frequency was inversely related to Th1 frequency (detectable HIV-1 RNA: P < 0.05; undetectable: P < 0.001), but positively related to Th2 frequency (detectable HIV-1 RNA: P < 0.01; undetectable: P < 0.001). T Reg activity was lower in patients with detectable plasma HIV-1 RNA than in patients with undetectable plasma HIV-1 RNA.
  
  
  CONCLUSIONS
  Increased T Reg frequencies in peripheral blood were related to low peripheral blood CD4 T-cell counts and polarization toward Th2 immune responses in HIV-infected patients.
authors.affiliation: Division of Thrombosis and Hemostasis, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Sachi
authors.initials: S
authors.lastname: Tsunemi
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Iwasaki
authors.forename: Takehito
authors.initials: T
authors.lastname: Imado
authors.forename: Satoshi
authors.initials: S
authors.lastname: Higasa
authors.forename: Eizo
authors.initials: E
authors.lastname: Kakishita
authors.forename: Takuma
authors.initials: T
authors.lastname: Shirasaka
authors.forename: Hajime
authors.initials: H
authors.lastname: Sano
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D015658:HIV Infections / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000097:blood; D015375:Receptors, Interleukin-2 / Q000097:blood*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D019562:Viral Load
chemical_list: D012367:RNA, Viral; D015375:Receptors, Interleukin-2