title: Reappearance of HIV multidrug-resistance in plasma and circulating lymphocytes after reintroduction of antiretroviral therapy.
abstract: BACKGROUND
  After the discontinuation of antiretroviral therapy in HIV-infected patients with highly resistant virus, the detectability of viral resistance mutations quickly decreases. To which extent this represents a true loss of resistance or rather a detectability phenomenon remains unclear.
  
  
  OBJECTIVE
  To monitor virologic response and resistance pattern during a non-strategic treatment interruption in the presence of highly drug-resistant viral strains.
  
  
  METHODS
  We performed serial genotypic resistance analyses on viral DNA isolated from a patient with a multidrug-resistant human immunodeficiency virus infection who discontinued and later on reintroduced antiretroviral therapy. Sequencing was performed on viral DNA from plasma as well as DNA from circulating leukocytes.
  
  
  RESULTS
  While under combination antiretroviral therapy with two nucleosidic reverse transcriptase inhibitors, a non-nucleosidic reverse transcriptase inhibitor and a protease inhibitor, the viral load of the patient was around five logs. Genotypic resistance to all available agents was detected during this time. Antiretroviral therapy was then interrupted, and 14 weeks later an almost complete reversion of the virus to wild type was observed. After introduction of a new antiretroviral therapy regimen, the reappearance of nearly all of the formerly present resistance mutations had to be noted within 6 weeks, including mutations without known relation to any of the drugs in the new regimen.
  
  
  CONCLUSIONS
  We obviously observed not the de novo appearance of a complex resistance pattern under just 6 weeks of potent antiretroviral therapy, but a reappearing archival strain of the virus. This finding provides evidence for subdetectable persistence of resistant variants during treatment interruptions. Therefore, resistance analyses from peripheral blood performed in times of treatment interruptions should be interpreted with caution as they may provide incomplete information about the resistance profile soon after reintroduction of therapy.
authors.affiliation: Institute for Interdisciplinary Infectiology and Immunology (IFI), Lohmuehlenstrasse 5, D-20099 Hamburg, Germany. d.albrecht@med2.uni-kiel.de
authors.forename: Dirk
authors.initials: D
authors.lastname: Albrecht
authors.forename: Bernhard
authors.initials: B
authors.lastname: Zöllner
authors.forename: Heinz-Hubert
authors.initials: HH
authors.lastname: Feucht
authors.forename: Thore
authors.initials: T
authors.lastname: Lorenzen
authors.forename: Rainer
authors.initials: R
authors.lastname: Laufs
authors.forename: Albrecht
authors.initials: A
authors.lastname: Stoehr
authors.forename: Andreas
authors.initials: A
authors.lastname: Plettenberg
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D002908:Chronic Disease; D004279:DNA, Viral / Q000187:drug effects; D024921:Drug Resistance, Multiple, Viral; D004359:Drug Therapy, Combination; D005838:Genotype; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008137:Longitudinal Studies; D008214:Lymphocytes / Q000821:virology; D008297:Male; D009154:Mutation; D016312:Treatment Refusal; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D004279:DNA, Viral