title: Thymic Function Impacts the Peripheral CD4/CD8 Ratio of HIV-Infected Subjects.
abstract: BACKGROUND
  The persistence of an inverted CD4/CD8 ratio has been extensively associated with the increased morbimortality of chronic human immunodeficiency virus (HIV)-infected subjects. Thymic function is crucial for the maintenance of T cell homeostasis. We explored the impact of thymic function on the CD4/CD8 ratio of HIV-infected subjects.
  
  
  METHODS
  In a cohort of 53 antiretroviral-naive HIV-infected subjects, the measure of thymic volume, as a representative marker for thymic function, was available at baseline and at 12, 24, and 48 weeks post antiretroviral treatment.
  
  
  RESULTS
  Baseline thymic volume was associated with the CD4/CD8 ratio ( Ρ: = 0.413, P = .002), being this association highly dependent on the CD4 T cell levels. In subjects who achieved undetectable viral load after treatment (n = 33), a higher baseline thymic volume was associated with a higher increase in CD4 T cell counts and a decreasing trend in CD8 T cell counts during follow-up. Moreover, the baseline thymic volume was independently associated with the normalization of the CD4/CD8 ratio after 96 weeks of treatment (odds ratio, 95% confidence interval: 1.95 (1.07-3.55); P = .03).
  
  
  CONCLUSIONS
  Our data indicate the relevance of the remaining thymic function before the start of treatment to the CD4/CD8 ratio of HIV- infected subjects and, hence, potentially, in their clinical progression.
authors.affiliation: Laboratory of Immunovirology, Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, Virgen del Rocío University Hospital/CSIC/University of Seville, Seville 41013, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Rosado-Sánchez
authors.affiliation: Laboratory of Immunovirology, Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, Virgen del Rocío University Hospital/CSIC/University of Seville, Seville 41013, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Herrero-Fernández
authors.affiliation: Laboratory of Immunovirology, Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, Virgen del Rocío University Hospital/CSIC/University of Seville, Seville 41013, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Genebat
authors.affiliation: Laboratory of Immunovirology, Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, Virgen del Rocío University Hospital/CSIC/University of Seville, Seville 41013, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Ruiz-Mateos
authors.affiliation: Laboratory of Immunovirology, Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, Virgen del Rocío University Hospital/CSIC/University of Seville, Seville 41013, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Leal
authors.affiliation: Laboratory of Immunovirology, Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, Virgen del Rocío University Hospital/CSIC/University of Seville, Seville 41013, Spain.
authors.forename: Yolanda M
authors.initials: YM
authors.lastname: Pacheco
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D015415:Biomarkers; D018791:CD4 Lymphocyte Count; D016516:CD4-CD8 Ratio; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy / Q000276:immunology* / Q000821:virology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D009929:Organ Size; D010641:Phenotype; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D015415:Biomarkers
keywords: CD4/CD8 ratio; HIV; antiretroviral naive.; delta-TRECs; thymic function