Development of In Vitro Resistance to HIV Among HAART-Treated Volunteers

Strategic Insights -

Researchers have identified the development of in vitro resistance to macrophage tropic and T-cell line adapted strains of HIV among HIV-positive asymptomatic volunteers undergoing HAART treatment. A study published in 1999 found that four out of five volunteers displayed a switch to the resistant phenotype on their first visit during treatment, and three remained resistant on a second visit a month later. The study suggests that resistance to HIV-1 may be associated with CD8-independent mechanisms.

Key Takeaways:

  • Four out of five HIV-positive asymptomatic volunteers switched to the resistant phenotype on their first visit during HAART treatment.
  • Three volunteers remained resistant to HIV-1 on a second visit a month later.
  • Resistance to HIV-1[MN] appeared to be CD8-dependent, as 7/7 cultures became susceptible to HIV-1[MN] after CD8(+) T-cell depletion.
  • Resistance to HIV-1[BAL] was at least partially CD8-independent, as only 2/7 cultures became susceptible to HIV-1[BAL].
  • None of the patients developed new or enhanced lymphoproliferative responses to HIV antigens.
  • The study suggests that additional arms of immunity may be involved in resistance to HIV-1.

Statistics:

  • 5 volunteers were initiated on HAART treatment.
  • 4 out of 5 volunteers displayed a switch to the resistant phenotype on their first visit during treatment.
  • 3 volunteers remained resistant on a second visit a month later.
  • 7 out of 7 cultures became susceptible to HIV-1[MN] after CD8(+) T-cell depletion.
  • 2 out of 7 cultures became susceptible to HIV-1[BAL] after CD8(+) T-cell depletion.

Sources:

  • David H. Schwartz, Renan C. Castillo, and Silvio Arango-Jaramillo. Department of Molecular Microbiology & Immunology, Johns Hopkins School of Hygiene, Baltimore, Maryland 21205. (CW Henderson Publisher www.newsfile.com)
  • Keystone Symposia HIV Vaccine Development: Opportunities and Challenges, held January 7-13, 1999, in Keystone, Colorado.
  • Journal of Infectious Diseases, 1997, 176(3):1168-74.