title: HIV-1 p24 and CD4+T cell count during boosted protease-inhibitor monotherapy in HIV-infected patients.
abstract: BACKGROUND
  Plasma HIV p24 is considered a significant predictor of CD4+T cell decline and progression to AIDS in HIV-infected patients. We evaluated the p24 levels in patients on triple therapy and after switching to ritonavir-boosted protease inhibitor monotherapy (mtPI/rtv), as well as the relationships with virological and immunological evolution.
  
  
  METHODS
  Plasma samples from patients participating in two studies of simplification to mtPI/rtv were analysed for presence of p24, using a boosted enzyme-linked immunosorbent assay specific for mature p24. Only patients with available samples at baseline (on triple therapy) and during a follow-up of at least 12 months after switching to mtPI/rtv were included.
  
  
  RESULTS
  A total of 233 samples from 51 patients were analysed. After switching to mtPI/rtv and a median follow-up of 24 months, 14 patients maintained continuous undetectable viraemia, and 37 patients experienced a total of 49 transient viraemic episodes. Unexpectedly, the evolutionary p24 patterns were uniform for most patients, both before and after switching to mtPI/rtv, independently of the virological behaviour, fitting into one of three categories: persistent undetectable p24 levels, positive p24, matching only with the viraemic episodes, and persistent detectable p24 levels. The last group showed lower CD4+T cell counts and percentages, as well as lower CD4+/CD8+T cell ratios after 12 and 24 months of follow up.
  
  
  CONCLUSIONS
  Treatment simplification to mtPI/rtv does not influence the behaviour of p24 in plasma. Patients with continuous positive p24, despite undetectable viraemia, showed worse immunological evolution.
authors.affiliation: Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Instituto de Biomedicina de Sevilla/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
authors.forename: Omar Jesus
authors.initials: OJ
authors.lastname: Benmarzouk-Hidalgo
authors.affiliation: Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Instituto de Biomedicina de Sevilla/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Torres-Cornejo
authors.affiliation: Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Instituto de Biomedicina de Sevilla/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Gutierrez-Valencia
authors.affiliation: Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Instituto de Biomedicina de Sevilla/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.
authors.forename: Pompeyo
authors.initials: P
authors.lastname: Viciana
authors.affiliation: Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Instituto de Biomedicina de Sevilla/Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain. Electronic address: lflopez@us.es.
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: López-Cortés
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000276:immunology*; D017320:HIV Protease Inhibitors / Q000627:therapeutic use*; D015497:HIV-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D019438:Ritonavir / Q000627:therapeutic use*
chemical_list: D017320:HIV Protease Inhibitors; D019438:Ritonavir
keywords: Boosted protease inhibitors; CD4 T(+) cell count; Inhibidores de la proteasa potenciados; Monoterapia; Monotherapy; Recuento de CD4(+); p24