title: Predictors of immunological failure after initial response to highly active antiretroviral therapy in HIV-1-infected adults: a EuroSIDA study.
abstract: BACKGROUND
  Factors that determine the immunological response to highly active antiretroviral therapy (HAART) are poorly defined.
  
  
  OBJECTIVE
  Our aim was to investigate predictors of immunological failure after initial CD4(+) response.
  
  
  METHODS
  Data were from EuroSIDA, a prospective, international, observational human immunodeficiency virus (HIV) type 1 cohort.
  
  
  RESULTS
  Of 2347 patients with an increase in CD4(+) cell count >or=100 cells/microL within 6-12 months of the initiation of HAART, 550 (23%) subsequently experienced immunological failure (CD4(+) count less than or equal to the pre-HAART value). The incidence of failure was 11.6 incidences/100 person-years of follow-up (95% confidence interval [CI], 10.2-13.4) during the first 12 months and decreased significantly over time (P<.0001). Independent predictors of immunological failure were pre-HAART CD4(+) cell count (per 50% higher; relative hazard [RH], 2.05; 95% CI, 1.83-2.31; P<.0001), time-updated virus load (per 1 log(10) higher; RH, 1.77; 95% CI, 1.64-1.92; P<.0001), and HIV-1 risk behavior (P=.047 for a global comparison of risk groups).
  
  
  CONCLUSIONS
  The risk of immunological failure in patients with an immunological response to HAART diminishes with a longer time receiving treatment and is associated with pretreatment CD4(+) cell count, ongoing viral replication, and intravenous drug use.
authors.affiliation: Hvidovre University Hospital, Copenhagen, Denmark. ubd@cphiv.dk
authors.forename: Ulrik Bak
authors.initials: UB
authors.lastname: Dragsted
authors.forename: Amanda
authors.initials: A
authors.lastname: Mocroft
authors.forename: Stefano
authors.initials: S
authors.lastname: Vella
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Viard
authors.forename: Ann-Britt E
authors.initials: AB
authors.lastname: Hansen
authors.forename: George
authors.initials: G
authors.lastname: Panos
authors.forename: Danielle
authors.initials: D
authors.lastname: Mercey
authors.forename: Ladislav
authors.initials: L
authors.lastname: Machala
authors.forename: Andrzej
authors.initials: A
authors.lastname: Horban
authors.forename: Jens D
authors.initials: JD
authors.lastname: Lundgren
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D005060:Europe; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications; D016896:Treatment Outcome; D014779:Virus Replication