title: HIV in the brain: RNA levels and patterns of zidovudine resistance.
abstract: OBJECTIVE
  To examine the association between HIV RNA levels, patterns of antiretroviral resistance, and neurologic status.
  
  
  METHODS
  Autopsy samples from 13 HIV-infected subjects were examined for HIV-1 viral RNA (vRNA), and viral reverse transcriptase (RT) genotype was determined. All subjects had been clinically characterized using standard instruments before death.
  
  
  RESULTS
  The median HIV-1 vRNA level in brain samples from subjects with moderate dementia was 7.79 log(10) copies/g (range 5.56 to 9.75 log(10) copies/g) compared with 5.44 log(10) copies/g (range 3.51 to 9.32 log(10) copies/g) for mildly demented subjects and 4.87 log(10) copies/g (3.51 to 6.86 log(10) copies/g) for those obtained from nondemented individuals. There were differences between subjects with moderate dementia and nondemented subjects (p = 0.0002) and between subjects with moderate and mild dementia (p = 0.0128). No significant differences among the groups were observed for vRNA levels in peripheral tissues. Some demented subjects had relatively low levels of HIV-1 vRNA, and paradoxically some nondemented subjects had high vRNA brain levels. Little subject effect in vRNA was noted in peripheral regions, but high regional variation in vRNA was noted within the brain. Patterns of the major zidovudine (ZDV) RT mutations in brain and peripheral tissues were concordant in most subjects. Subjects with longer duration of exposure to ZDV tended to have lower brain vRNA levels and a greater number of RT mutations than those with limited to no exposure.
  
  
  CONCLUSIONS
  The presence and severity of HIV dementia correlates with the levels of productive HIV replication within the brain. Other pathophysiologic events (including macrophage activation) probably also contribute to neurologic dysfunction.
authors.affiliation: Glaxo Wellcome, Inc., Research Triangle Park, NC, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: McClernon
authors.forename: R
authors.initials: R
authors.lastname: Lanier
authors.forename: S
authors.initials: S
authors.lastname: Gartner
authors.forename: P
authors.initials: P
authors.lastname: Feaser
authors.forename: C A
authors.initials: CA
authors.lastname: Pardo
authors.forename: M
authors.initials: M
authors.lastname: St  Clair
authors.forename: Q
authors.initials: Q
authors.lastname: Liao
authors.forename: J C
authors.initials: JC
authors.lastname: McArthur
mesh_terms: D015526:AIDS Dementia Complex / Q000188:drug therapy* / Q000821:virology; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D001921:Brain / Q000821:virology; D018791:CD4 Lymphocyte Count; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007113:Immunity, Innate; D009154:Mutation; D012367:RNA, Viral / Q000032:analysis; D012720:Severity of Illness Index; D014779:Virus Replication; D015215:Zidovudine / Q000627:therapeutic use*
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral; D015215:Zidovudine; D054303:HIV Reverse Transcriptase