title: Viro-immunological response and emergence of resistance in HIV-infected women receiving combination antiretroviral regimens for the prevention of mother-to-child transmission in Malawi.
abstract: OBJECTIVE
  To identify factors associated with detectable viral load and the emergence of drug resistance in a cohort of HIV-infected pregnant women in Malawi receiving antiretroviral combination regimens for the prevention of mother-to-infant transmission.
  
  
  METHODS
  The study included 260 treatment-naive women who had received a three-drug nevirapine-based regimen from week 25 of gestational age until 6 months after delivery. HIV RNA was determined at month 6 and drug resistance was assessed if viral load was >50 copies/mL. Attendance at the scheduled follow-up visits was used as an indirect measure of treatment adherence.
  
  
  RESULTS
  The rate of detectable HIV RNA at 6 months was 9.6% (25/260). The only significant predictor of this occurrence was the presence of ≥1 missed visit during follow-up (P = 0.012). Resistance was assessed in 19 of these women: 7 (37%) had a wild-type virus and the other 12 (63%) had resistance-associated mutations (nucleoside reverse transcriptase inhibitor, 7/12; non-nucleoside reverse transcriptase inhibitor, 11/12). Three of 12 cases (25%) in which mutations were detected had a viral load <1000 copies/mL. The emergence of resistance was not correlated with the presence of baseline mutations in either plasma or archived DNA.
  
  
  CONCLUSIONS
  In this cohort of women, detectable HIV RNA 6 months post-partum was infrequent and associated with low adherence to the treatment programme. Mutations were present in 63% of the women with detectable viral load at 6 months who had samples available for resistance testing. The impact of resistance on treatment re-initiation in women discontinuing drugs after the risk of transmission has ceased can be limited.
authors.affiliation: Department of Biomedicine and Prevention, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Palombi
authors.forename: Clementina M
authors.initials: CM
authors.lastname: Galluzzo
authors.forename: Maria F
authors.initials: MF
authors.lastname: Pirillo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Liotta
authors.forename: Mauro
authors.initials: M
authors.lastname: Andreotti
authors.forename: Haswell
authors.initials: H
authors.lastname: Jere
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Sagno
authors.forename: Richard
authors.initials: R
authors.lastname: Luhanga
authors.forename: Sandro
authors.initials: S
authors.lastname: Mancinelli
authors.forename: Susanna
authors.initials: S
authors.lastname: Ceffa
authors.forename: Roberta
authors.initials: R
authors.lastname: Amici
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Marazzi
authors.forename: Stefano
authors.initials: S
authors.lastname: Vella
authors.forename: Marina
authors.initials: M
authors.lastname: Giuliano
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015331:Cohort Studies; D024882:Drug Resistance, Viral; D005260:Female; D006678:HIV / Q000187:drug effects* / Q000302:isolation & purification; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000517:prevention & control / Q000821:virology*; D006801:Humans; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D008295:Malawi; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D012367:RNA, Viral / Q000097:blood; D019562:Viral Load; D055815:Young Adult
chemical_list: D044966:Anti-Retroviral Agents; D012367:RNA, Viral
keywords: antiretroviral therapy; breastfeeding; drug resistance; pregnancy