title: Longitudinal evaluation of regulatory T-cell dynamics on HIV-infected individuals during the first 2 years of therapy.
abstract: A sizeable percentage of individuals infected by HIV and on antiretroviral therapy (ART) fail to increase their CD4 T-cells to satisfactory levels. The percentage of regulatory T-cells (Tregs) has been suggested to contribute to this impairment. This study aimed to address this question and to expand the analysis of Tregs subpopulations during ART.
  
  
  
  Longitudinal follow-up of 81 HIV-infected individuals during the first 24 months on ART.
  
  
  
  CD4 T-cell counts, Tregs percentages, and specific Tregs subpopulations were evaluated at ART onset, 2, 6, 9, 12, 16, 20, and 24 months of ART (five individuals had no Tregs information at baseline).
  
  
  
  The slope of CD4 T-cell recovery was similar for individuals with moderate and with severe lymphopenia at ART onset. No evidence was found for a contribution of the baseline Tregs percentages on the CD4 T-cell counts recovery throughout ART. In comparison to uninfected individuals, Tregs percentages were higher at ART onset only for patients with less than 200 cells/μl at baseline and decreased afterwards reaching normal values. Within Tregs, the percentage of naive cells remained low in these patients. Reduced thymic export and increased proliferation of Tregs vs. conventional CD4 T cells might explain these persistent alterations.
  
  
  
  No effect of Tregs percentages at baseline was detected on CD4 T-cell recovery. However, profound alterations on Tregs subpopulations were consistently observed throughout ART for patients with severe lymphopenia at ART onset.
authors.affiliation: aLife and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga bICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães cInfectious Diseases Service of the Centro Hospitalar do Porto, Hospital Joaquim Urbano Unit, Porto, Portugal. *Claudia Nobrega and Ana Horta contributed equally to the writing of this article.
authors.forename: Claudia
authors.initials: C
authors.lastname: Nobrega
authors.forename: Ana
authors.initials: A
authors.lastname: Horta
authors.forename: Vítor
authors.initials: V
authors.lastname: Coutinho-Teixeira
authors.forename: Ana
authors.initials: A
authors.lastname: Martins-Ribeiro
authors.forename: Ana
authors.initials: A
authors.lastname: Baldaia
authors.forename: Rita
authors.initials: R
authors.lastname: Rb-Silva
authors.forename: Catarina L
authors.initials: CL
authors.lastname: Santos
authors.forename: Rui
authors.initials: R
authors.lastname: Sarmento-Castro
authors.forename: Margarida
authors.initials: M
authors.lastname: Correia-Neves
mesh_terms: D000328:Adult; D000368:Aged; D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D007111:Immunity, Cellular; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D044966:Anti-Retroviral Agents