title: Thymic volume predicts CD4 T-cell decline in HIV-infected adults under prolonged treatment interruption.
abstract: OBJECTIVE
  To analyze the predictive capacity of thymic volume in CD4 T-cell loss after treatment interruption in HIV-infected patients with high nadir CD4 count.
  
  
  METHODS
  Thirty-nine HIV-infected patients with CD4 counts greater than or equal to 500 cells/microL, nadir CD4 counts greater than or equal to 250 cells/microL, and plasma viral loads less than 50 copies/mL for at least the past 12 months began a treatment interruption program. The event of interest for this study was the decrease of CD4 count below 350 cells/microL. Kaplan-Meier curves were used for all time-to-event analyses, and log-rank tests were used for comparison between groups in the univariate analysis. All variables with statistical association with CD4 T-cell loss were analyzed using multivariate Cox proportional hazards regression models.
  
  
  RESULTS
  Twenty-three percent of the patients had a decrease in CD4 count to less than 350 cells/microL. In the univariate analysis, only thymic volume was statistically significant with this event (P = 0.02). Nadir CD4 count nearly reached statistical significance. However, age, sex, HCV coinfection, CD4 count, T-cell receptor excision circle-bearing cells, and early viral load rebound did not show statistical differences. Thymic volume and CD4 T-cell loss were independently associated using Cox proportional hazards regression model (P = 0.04; relative risk, 0.76; 95% confidence interval, 0.59-0.99).
  
  
  CONCLUSIONS
  In this study, we demonstrate for the first time that thymic volume predicts CD4 T-cell loss in patients with nadir CD4 count greater than or equal to 250 cells/muL under treatment interruption.
authors.affiliation: Viral Hepatitis and AIDS Unit, Service of Internal Medicine,Virgen del Rocío University Hospital, Seville, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Molina-Pinelo
authors.forename: Jorge
authors.initials: J
authors.lastname: Vivancos
authors.forename: Beatriz
authors.initials: B
authors.lastname: De Felipe
authors.forename: Natalia
authors.initials: N
authors.lastname: Soriano-Sarabia
authors.forename: Angela
authors.initials: A
authors.lastname: Valladares
authors.forename: Rafael
authors.initials: R
authors.lastname: De la Rosa
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vallejo
authors.forename: Manuel
authors.initials: M
authors.lastname: Leal
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D004334:Drug Administration Schedule; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D016016:Proportional Hazards Models; D013223:Statistics as Topic; D013950:Thymus Gland / Q000276:immunology / Q000473:pathology*; D013997:Time Factors; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents