title: Residual viremia is preceding viral blips and persistent low-level viremia in treated HIV-1 patients.
abstract: BACKGROUND
  It has been suggested that low-level viremia or blips in HIV-infected patients on antiretroviral treatment are related to assay variation and/or increased sensitivity of new commercial assays. The 50-copy cut-off for virologic failure is, therefore, under debate.
  
  
  METHODS
  Treated patients with low-level viremia (persistent viral loads (VL) of 50-1000 copies/mL, group A, N = 16) or a blip (single detectable VL, group B, N = 77) were compared to a control group (consistently suppressed viremia since start therapy (<50 copies/mL), N = 79). Residual viremia (detectable viral RNA <50 copies/ml) in the year preceding the first VL above 50 copies/mL (T0) was determined using Roche Cobas-Amplicor v1.5 or CAP-CTM v2.0. Subsequent virologic failure (2 consecutive VLs>500 or 1 VL>1000 copies/mL that was not followed by a VL<50 copies/mL; median follow up 34 months) was assessed.
  
  
  RESULTS
  Significantly more patients in groups A and B had residual viremia in the year preceding T0 compared to controls (50% and 19% vs 3% respectively; p<0.001). Residual viremia was associated with development of low-level viremia or blips (OR 10.9 (95% CI 2.9-40.6)). Subsequent virologic failure was seen more often in group A (3/16) and B (2/77) than in the control group (0/79).
  
  
  CONCLUSIONS
  Residual viremia is associated with development of blips and low-level viremia. Virologic failure occurred more often in patients with low-level viremia. These results suggest that low-level viremia results from viral production/replication rather than only assay variation.
authors.affiliation: Department of Medical Microbiology, Virology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Laura Marije
authors.initials: LM
authors.lastname: Hofstra
authors.affiliation: Department of Internal Medicine and Infectious Diseases, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Tania
authors.initials: T
authors.lastname: Mudrikova
authors.affiliation: Department of Medical Microbiology, Virology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Arjen J
authors.initials: AJ
authors.lastname: Stam
authors.affiliation: Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Otto
authors.affiliation: Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Kiki
authors.initials: K
authors.lastname: Tesselaar
authors.affiliation: Department of Medical Microbiology, Virology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Monique
authors.initials: M
authors.lastname: Nijhuis
authors.affiliation: Department of Medical Microbiology, Virology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Annemarie M J
authors.initials: AM
authors.lastname: Wensing
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis; D019562:Viral Load; D014766:Viremia / Q000821:virology*
chemical_list: D044966:Anti-Retroviral Agents; D012367:RNA, Viral