title: Viral phenotype, antiretroviral resistance and clinical evolution in human immunodeficiency virus-infected children.
abstract: BACKGROUND
  The syncytium-inducing (SI) viral phenotype and the emergence of viral strains resistant to zidovudine have been described in persons infected with HIV, and in some cases they have been associated with poor prognosis.
  
  
  METHODS
  HIV isolates obtained from 37 HIV-infected children were analyzed to determine whether the SI viral phenotype and the mutation on the 215 position of the reverse transcriptase (M215) could be used as markers of disease progression. We performed peripheral blood coculture mononuclear cells, and we analyzed the induction of syncytia using the MT-2 cell line. The emergence of mutations on the 215 position was determined by PCR.
  
  
  RESULTS
  We found a statistically significant association (P < 0.05) between SI viral phenotype and (1) recurrent serious bacterial infections, (2) absolute CD4+ cell counts <2 SD, (3) progression to AIDS and (4) death. Sixty percent of the children treated with zidovudine developed 215 mutant viral strains without statistically significant association with clinical or immunologic findings. The SI viral phenotype was statistically associated with the presence of the 215 mutation (P < 0.05).
  
  
  CONCLUSIONS
  SI viral phenotype is a marker associated with a poor clinical and immunologic progression of the disease and it may facilitate the emergence of mutant strains in children treated with zidovudine.
authors.affiliation: Centro de Investigación Clínica, Servicio de Pediatría, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Mellado
authors.forename: M J
authors.initials: MJ
authors.lastname: Cilleruelo
authors.forename: M
authors.initials: M
authors.lastname: Ortiz
authors.forename: J
authors.initials: J
authors.lastname: Villota
authors.forename: M
authors.initials: M
authors.lastname: García
authors.forename: M L
authors.initials: ML
authors.lastname: Perez-Jurado
authors.forename: G
authors.initials: G
authors.lastname: Barreiro
authors.forename: P
authors.initials: P
authors.lastname: Martín-Fontelos
authors.forename: A
authors.initials: A
authors.lastname: Bernal
mesh_terms: D000293:Adolescent; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D005260:Female; D006678:HIV / Q000145:classification*; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D010641:Phenotype; D011446:Prospective Studies; D015215:Zidovudine / Q000627:therapeutic use*
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine