Dr. Nettles is an infectious disease fellow at Johns Hopkins University who has spent the research years of his fellowship working with his mentors Drs. Siliciano, Gallant, and Moore on the optimization and clinical application of an ultra-sensitive HIV-1 genotype assay. Through this award, Dr. Nettles hopes to conduct basic science research on HIV resistance testing as a faculty member of the Division of Infectious Diseases. To determine the clinical and evolutionary significance of HIV-1 resistance during periods of low-level and rapidly decreasing plasma viral loads, Dr. Nettles plans to develop better methods for monitoring resistance to antiretroviral therapy using novel RT-PCR ultra-sensitive genotypic resistance assays. He proposes to define the predictors, etiology, and consequence of persistent low levels of viremia in Johns Hopkins Moore Clinic patients with and without baseline drug-resistance mutations. Furthermore, he will characterize and determine the significance of intermittent low-level HIV-1 viremia (""""""""blips"""""""") in patients on highly active antiretroviral therapy through intense drug level, viral load, and genotypic monitoring supported by a General Clinical Research Center. Finally, he will determine the utility of genotype resistance testing on antiretroviral-experienced patients after reinitiation of antiretroviral therapy at various time points during decay in plasma viral load. We anticipate that this will lead to a better understanding of the most effective use of genotype resistance testing and antiretroviral therapy for the 42 million people currently infected with HIV-1. Since little direct patient contact is anticipated, Dr. Nettles plans to conduct these studies through a K08 award. Dr. Nettles will attend virology and infectious disease seminars as well as courses through the Department of Medicine and School of Public Health. This, along with excellent mentorship and the supportive environment at Johns Hopkins University, will provide Dr. Nettles with the skills he needs to develop into an independent researcher studying HIV resistance.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Clinical Investigator Award (CIA) (K08)
Project #
Application #
Study Section
Acquired Immunodeficiency Syndrome Research Review Committee (AIDS)
Program Officer
Ussery, Michael A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Johns Hopkins University
Internal Medicine/Medicine
Schools of Medicine
United States
Zip Code
Bailey, Justin R; Sedaghat, Ahmad R; Kieffer, Tara et al. (2006) Residual human immunodeficiency virus type 1 viremia in some patients on antiretroviral therapy is dominated by a small number of invariant clones rarely found in circulating CD4+ T cells. J Virol 80:6441-57
Lee, Patricia K; Kieffer, Tara L; Siliciano, Robert F et al. (2006) HIV-1 viral load blips are of limited clinical significance. J Antimicrob Chemother 57:803-5
Nettles, Richard E; Kieffer, Tara L; Parsons, Teresa et al. (2006) Marked intraindividual variability in antiretroviral concentrations may limit the utility of therapeutic drug monitoring. Clin Infect Dis 42:1189-96
Monie, Daphne; Simmons, Rachel P; Nettles, Richard E et al. (2005) A novel assay allows genotyping of the latent reservoir for human immunodeficiency virus type 1 in the resting CD4+ T cells of viremic patients. J Virol 79:5185-202
Nettles, Richard E; Keiffer, Tara L; Cofrancesco Jr, Joseph et al. (2005) Psychological distress and physical pain appear to have no short-term adverse impact on plasma HIV-1 RNA levels in patients on successful HAART. HIV Clin Trials 6:262-71
Nettles, Richard E; Kieffer, Tara L; Kwon, Patty et al. (2005) Intermittent HIV-1 viremia (Blips) and drug resistance in patients receiving HAART. JAMA 293:817-29