title: Longitudinal assessment of interleukin 7 plasma levels in HIV-infected patients in the absence of and under antiretroviral therapy.
abstract: BACKGROUND
  Cross-sectional studies in HIV-positive patients have suggested that interleukin 7 (IL-7) may increase in parallel to CD4 decline during the natural course of HIV infection. We tested this hypothesis in a longitudinal study examining the evolution of IL-7 and CD4 counts in 2 different scenarios.
  
  
  METHODS
  IL-7 and CD4 counts were regularly monitored in 30 drug-naive patients during a follow-up period of 46 ± 14 months in the absence of therapy and in 42 patients who started highly active antiretroviral therapy and maintained undetectable viremia for 2 years. Multivariate linear regression analysis was used to ascertain what factors were associated with IL-7 variations during follow-up.
  
  
  RESULTS
  In antiretroviral therapy-naive patients, CD4 counts significantly decreased (P < 0.0001), whereas plasma HIV-RNA and IL-7 levels remained fairly stable. In patients on highly active antiretroviral therapy, CD4 counts significantly increased (P < 0.0001) and IL-7 tended to decrease (P = 0.1). There was no correlation between CD4 and IL-7 variations either in the naive or in the treated population. The only parameter significantly associated with IL-7 variation during follow-up was its baseline level that showed a negative correlation.
  
  
  CONCLUSIONS
  In HIV patients with low or moderate degree of immunodeficiency, CD4 counts and plasma IL-7 levels do not evolve in parallel, suggesting that other factors different from CD4 counts must be involved in the upregulation of IL-7 observed in HIV infection.
authors.affiliation: Infectious Diseases Department, Hospital Carlos III, Madrid, Spain.
authors.forename: Norma I
authors.initials: NI
authors.lastname: Rallón
authors.forename: Mariola
authors.initials: M
authors.lastname: López
authors.forename: Sara
authors.initials: S
authors.lastname: Lozano
authors.forename: José M
authors.initials: JM
authors.lastname: Sempere-Ortells
authors.forename: Vincent
authors.initials: V
authors.lastname: Soriano
authors.forename: José M
authors.initials: JM
authors.lastname: Benito
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy*; D006801:Humans; D015851:Interleukin-7 / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D012367:RNA, Viral / Q000097:blood; D012189:Retrospective Studies; D013997:Time Factors; D014766:Viremia
chemical_list: D019380:Anti-HIV Agents; D015851:Interleukin-7; D012367:RNA, Viral