title: Acute decrease in HIV-1 viral load after initiation of zidovudine therapy: implications for interrupting vertical transmission.
abstract: Use of zidovudine (AZT) in pregnant women has recently been reported to reduce the rate of vertical transmission of human immunodeficiency virus type 1 (HIV-1) possibly through a reduction in maternal viral load. To determine how quickly AZT is able to reduce viral load, infectious virus and plasma HIV-1 RNA were sequentially measured in an HIV-1-infected patient at short intervals (hours) after initiation of oral AZT. Peripheral blood samples were collected at baseline, 1, 2, 4, 8, 12, 24, 48 hours, and 1 week after initiation of AZT therapy (500 mg/day) for quantitative plasma HIV-1 RNA levels, p24 antigen levels, and AZT levels. Quantitative HIV-1 peripheral blood mononuclear cell and plasma cultures, CD4 cell counts, and MT-2 cell assays for syncytium-inducing phenotype were performed at baseline, 1, 2 days, and 1 week after initiation of AZT therapy. A significant drop in viral load did not occur until after 24-48 hours. AZT should probably be administered at least 2 days prior to anticipated delivery, if a reduced maternal viral load is responsible for AZT's efficacy in preventing vertical transmission.
authors.affiliation: Institute of Pathology and Department of Geographic Medicine, Case Western Reserve University, University Hospitals of Cleveland, OH, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Jackson
mesh_terms: D018791:CD4 Lymphocyte Count; D016655:HIV Core Protein p24 / Q000032:analysis; D006679:HIV Seropositivity / Q000188:drug therapy*; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000032:analysis; D013997:Time Factors; D014766:Viremia / Q000821:virology; D015215:Zidovudine / Q000627:therapeutic use*
chemical_list: D016655:HIV Core Protein p24; D012367:RNA, Viral; D015215:Zidovudine