title: [Frequency and characteristics of patients treated with zidovudine and absence of progression of HIV infection].
abstract: BACKGROUND
  the efficacy of zidovudine (ZDV) is lost in many treated individuals after a few weeks or months of monotherapy. The development of drug resistance seems to explain this adverse event. However, some individuals seem to persistently benefit clinically and immunologically from ongoing ZDV monotherapy. The degree and causes of this phenomenon remain unclear.
  
  
  METHODS
  we studied 280 HIV-infected patients who have been receiving ZDV monotherapy for more than 18 months (mean 28 +/- 7 months), and whom has a CD4+ count between 200 and 500 x 10(6)/l at baseline. We classified them into two groups: Non-progressors with ZDV (NP-ZDV), subjects with an increase or a reduction < 15% in the CD4+ count; and Progressors with ZDV (P-ZDV), subjects showing a decline in the CD4 count > 15%. Epidemiological, immunological and virological features of each group were compared.
  
  
  RESULTS
  the prevalence of NP-ZDV in this population was 15.7% (44/280). Age, gender, and risk behaviour were not significantly different in NP-ZDV and P-ZDV. Although the CD4/CD8 ratio, as well as the CD45R0/CD45RA ratio into the CD4+ subpopulation, were higher in NP-ZDV than in P-ZDV, the values did not achieve statistical significance. Virological studies were performed on 36 (81.8%) NP-ZDV and 55 (23.3%) P-ZDV. Mean HIV-RNA titer was higher in P-ZDV than in NP-ZDV (8.4 x 10(4) vs. 1.5 x 10(3) copies/ml; p < 0.01). Virus isolation from circulating mononuclear cells was made more frequently in P-ZDV than in NP-ZDV (90.9% vs. 81.5%), although it did not achieve statistical significance. The syncitium-inducing (SI) phenotype was detected in more than a quarter (27.3%) of P-ZDV but was absent in NP-ZDV (p < 0.01). The prevalence of RT mutations at codon 215 was much lower in NP-ZDV than in P-ZDV, and it showed a strong statistical significance (13.9% vs. 74.5%; p < 0.01).
  
  
  CONCLUSIONS
  prolonged (> 2 years) lack of immunological and clinical progression can be observed in 15% of HIV-infected persons with mild immunosuppression, undertaking ZDV monotherapy. This effect seems to be associated with a characteristic virological profile, in which a low viral load, the absence of SI phenotype, and a lack of development of ZDV-resistance are the most relevant features.
authors.affiliation: Servicio de Enfermedades Infecciosas, Instituto de Salud Carlos III, Madrid.
authors.forename: V
authors.initials: V
authors.lastname: Soriano
authors.forename: A
authors.initials: A
authors.lastname: Heredia
authors.forename: A
authors.initials: A
authors.lastname: Mas
authors.forename: A
authors.initials: A
authors.lastname: Vallejo
authors.forename: G
authors.initials: G
authors.lastname: Garćia-Lerma
authors.forename: R
authors.initials: R
authors.lastname: Bravo
authors.forename: M
authors.initials: M
authors.lastname: Gómez-Cano
authors.forename: N
authors.initials: N
authors.lastname: Villalba
authors.forename: V
authors.initials: V
authors.lastname: Moreno
authors.forename: F
authors.initials: F
authors.lastname: Laguna
authors.forename: E
authors.initials: E
authors.lastname: Valencia
authors.forename: P
authors.initials: P
authors.lastname: Martínez
authors.forename: J
authors.initials: J
authors.lastname: González-Lahoz
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D018450:Disease Progression; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D015215:Zidovudine / Q000627:therapeutic use*
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine