title: A stable CC-chemokine receptor (CCR)-5 tropic virus is correlated with the persistence of HIV RNA at less than 2.5 copies in successfully treated naïve subjects.
abstract: BACKGROUND
  To determine if tropism for CXCR4 or CCR5 correlates with cellular HIV DNA load, residual viraemia and CD4 count in 219 successfully treated naive subjects with HIV infection enrolled in five infectious diseases units in Northeastern Italy.
  
  
  METHODS
  A subset of subjects, achieving plasma HIV RNA level <50 copies/ml after initiation of first-line therapy and maintaining it until follow-up time points, was retrospectively selected from a prospective cohort. Blood samples were collected before the beginning of therapy (T0), at the first follow-up time (T1) and, when available, at a second (T2) follow-up time.
  
  
  RESULTS
  HIV DNA, CD4 count and plasma viraemia were available from all 219 patients at T0 and T1, and in 86 subjects at T2, while tropism determinations were available from 109 subjects at T0, 219 at T1, and from 86 subjects at T2. Achieving residual viraemia <2.5 copies/ml at T1 correlated with having the same condition at T2 (p = 0.0007). X4 tropism at T1 was negatively correlated with the possibility of achieving viraemia<2.5 copies/ml at T2 (p = 0.0076). T1-T2 tropism stability was significant (p <0.0001). T0 tropism correlated with T1 and T2 tropism (p < 0.001); therefore the stability of the tropism over the two follow-up periods was significant (p = 0.0003). An effective viremic suppression (viraemia<2.5 copies/ml) correlated with R5 coreceptor affinity (p= 0.047).
  
  
  CONCLUSIONS
  The tropism of archived virus was stable during an effective treatment, with 15-18% of subjects switching over time, despite a viraemia<50 copies/ml. R5 tropism and its stability were related to achieving and maintaining viraemia<2.5 copies/ml.
authors.affiliation: Department of Molecular Medicine, University of Padova, Padova, Italy. saverio.parisi@unipd.it
authors.forename: Saverio Giuseppe
authors.initials: SG
authors.lastname: Parisi
authors.forename: Samantha
authors.initials: S
authors.lastname: Andreis
authors.forename: Carlo
authors.initials: C
authors.lastname: Mengoli
authors.forename: Renzo
authors.initials: R
authors.lastname: Scaggiante
authors.forename: Mario
authors.initials: M
authors.lastname: Cruciani
authors.forename: Roberto
authors.initials: R
authors.lastname: Ferretto
authors.forename: Vinicio
authors.initials: V
authors.lastname: Manfrin
authors.forename: Sandro
authors.initials: S
authors.lastname: Panese
authors.forename: Monica
authors.initials: M
authors.lastname: Basso
authors.forename: Caterina
authors.initials: C
authors.lastname: Boldrin
authors.forename: Stefania
authors.initials: S
authors.lastname: Bressan
authors.forename: Loredana
authors.initials: L
authors.lastname: Sarmati
authors.forename: Massimo
authors.initials: M
authors.lastname: Andreoni
authors.forename: Giorgio
authors.initials: G
authors.lastname: Palù
mesh_terms: D000328:Adult; D000368:Aged; D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D004279:DNA, Viral / Q000097:blood; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy / Q000276:immunology / Q000821:virology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood; D019713:Receptors, CCR5 / Q000276:immunology*; D019562:Viral Load; D056189:Viral Tropism
chemical_list: D044966:Anti-Retroviral Agents; D004279:DNA, Viral; D012367:RNA, Viral; D019713:Receptors, CCR5