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1.  The Contribution of Viral Genotype to Plasma Viral Set-Point in HIV Infection 
PLoS Pathogens  2014;10(5):e1004112.
Disease progression in HIV-infected individuals varies greatly, and while the environmental and host factors influencing this variation have been widely investigated, the viral contribution to variation in set-point viral load, a predictor of disease progression, is less clear. Previous studies, using transmission-pairs and analysis of phylogenetic signal in small numbers of individuals, have produced a wide range of viral genetic effect estimates. Here we present a novel application of a population-scale method based in quantitative genetics to estimate the viral genetic effect on set-point viral load in the UK subtype B HIV-1 epidemic, based on a very large data set. Analyzing the initial viral load and associated pol sequence, both taken before anti-retroviral therapy, of 8,483 patients, we estimate the proportion of variance in viral load explained by viral genetic effects to be 5.7% (CI 2.8–8.6%). We also estimated the change in viral load over time due to selection on the virus and environmental effects to be a decline of 0.05 log10 copies/mL/year, in contrast to recent studies which suggested a reported small increase in viral load over the last 20 years might be due to evolutionary changes in the virus. Our results suggest that in the UK epidemic, subtype B has a small but significant viral genetic effect on viral load. By allowing the analysis of large sample sizes, we expect our approach to be applicable to the estimation of the genetic contribution to traits in many organisms.
Author Summary
HIV viral load, the amount of virus in the blood, is an important predictor of rate of CD4+ cell decline, time to AIDS and onwards transmission. Plasma viral load is influenced by many environmental and host factors, but the contribution of the viral genome is not yet clear. We have adapted a method from quantitative genetics which considers the viral phylogeny as a pedigree, permitting analysis of large cohort-derived datasets for the first time. We found the viral genome contributes significantly to the level of the set point viral load, but only determines about 6% of the variation in this property in this population. Our study also suggests that the change over time in mean plasma viral load described in some recent studies has not been due to a change in the component of viral load that is contributed by viral genotype.
PMCID: PMC4006911  PMID: 24789308
2.  Persistence of HIV-1 Transmitted Drug Resistance Mutations 
The Journal of Infectious Diseases  2013;208(9):1459-1463.
There are few data on the persistence of individual human immunodeficiency virus type 1 (HIV-1) transmitted drug resistance (TDR) mutations in the absence of selective drug pressure. We studied 313 patients in whom TDR mutations were detected at their first resistance test and who had a subsequent test performed while ART-naive. The rate at which mutations became undetectable was estimated using exponential regression accounting for interval censoring. Most thymidine analogue mutations (TAMs) and T215 revertants (but not T215F/Y) were found to be highly stable, with NNRTI and PI mutations being relatively less persistent. Our estimates are important for informing HIV transmission models.
PMCID: PMC3789571  PMID: 23904291
persistence; transmitted; HIV-1; resistance; mutations
3.  Low frequency of genotypic resistance in HIV-1-infected patients failing an atazanavir-containing regimen: a clinical cohort study 
Dolling, David I. | Dunn, David T. | Sutherland, Katherine A. | Pillay, Deenan | Mbisa, Jean L. | Parry, Chris M. | Post, Frank A. | Sabin, Caroline A. | Cane, Patricia A. | Aitken, Celia | Asboe, David | Webster, Daniel | Cane, Patricia | Castro, Hannah | Dunn, David | Dolling, David | Chadwick, David | Churchill, Duncan | Clark, Duncan | Collins, Simon | Delpech, Valerie | Geretti, Anna Maria | Goldberg, David | Hale, Antony | Hué, Stéphane | Kaye, Steve | Kellam, Paul | Lazarus, Linda | Leigh-Brown, Andrew | Mackie, Nicola | Orkin, Chloe | Rice, Philip | Pillay, Deenan | Phillips, Andrew | Sabin, Caroline | Smit, Erasmus | Templeton, Kate | Tilston, Peter | Tong, William | Williams, Ian | Zhang, Hongyi | Zuckerman, Mark | Greatorex, Jane | Wildfire, Adrian | O'Shea, Siobhan | Mullen, Jane | Mbisa, Tamyo | Cox, Alison | Tandy, Richard | Hale, Tony | Fawcett, Tracy | Hopkins, Mark | Ashton, Lynn | Booth, Claire | Garcia-Diaz, Ana | Shepherd, Jill | Schmid, Matthias L. | Payne, Brendan | Hay, Phillip | Rice, Phillip | Paynter, Mary | Bibby, David | Kirk, Stuart | MacLean, Alasdair | Gunson, Rory | Coughlin, Kate | Fearnhill, Esther | Fradette, Lorraine | Porter, Kholoud | Ainsworth, Jonathan | Anderson, Jane | Babiker, Abdel | Fisher, Martin | Gazzard, Brian | Gilson, Richard | Gompels, Mark | Hill, Teresa | Johnson, Margaret | Kegg, Stephen | Leen, Clifford | Nelson, Mark | Palfreeman, Adrian | Post, Frank | Sachikonye, Memory | Schwenk, Achim | Walsh, John | Huntington, Susie | Jose, Sophie | Thornton, Alicia | Glabay, Adam | Orkin, C. | Garrett, N. | Lynch, J. | Hand, J. | de Souza, C. | Fisher, M. | Perry, N. | Tilbury, S. | Gazzard, B. | Nelson, M. | Waxman, M. | Asboe, D. | Mandalia, S. | Delpech, V. | Anderson, J. | Munshi, S. | Korat, H. | Welch, J. | Poulton, M. | MacDonald, C. | Gleisner, Z. | Campbell, L. | Gilson, R. | Brima, N. | Williams, I. | Schwenk, A. | Ainsworth, J. | Wood, C. | Miller, S. | Johnson, M. | Youle, M. | Lampe, F. | Smith, C. | Grabowska, H. | Chaloner, C. | Puradiredja, D. | Walsh, J. | Weber, J. | Ramzan, F. | Mackie, N. | Winston, A. | Leen, C. | Wilson, A. | Allan, S. | Palfreeman, A. | Moore, A. | Wakeman, K.
Journal of Antimicrobial Chemotherapy  2013;68(10):2339-2343.
To determine protease mutations that develop at viral failure for protease inhibitor (PI)-naive patients on a regimen containing the PI atazanavir.
Resistance tests on patients failing atazanavir, conducted as part of routine clinical care in a multicentre observational study, were randomly matched by subtype to resistance tests from PI-naive controls to account for natural polymorphisms. Mutations from the consensus B sequence across the protease region were analysed for association and defined using the IAS-USA 2011 classification list.
Four hundred and five of 2528 (16%) patients failed therapy containing atazanavir as a first PI over a median (IQR) follow-up of 1.76 (0.84–3.15) years and 322 resistance tests were available for analysis. Recognized major atazanavir mutations were found in six atazanavir-experienced patients (P < 0.001), including I50L and N88S. The minor mutations most strongly associated with atazanavir experience were M36I, M46I, F53L, A71V, V82T and I85V (P < 0.05). Multiple novel mutations, I15S, L19T, K43T, L63P/V, K70Q, V77I and L89I/T/V, were also associated with atazanavir experience.
Viral failure on atazanavir-containing regimens was not common and major resistance mutations were rare, suggesting that adherence may be a major contributor to viral failure. Novel mutations were described that have not been previously documented.
PMCID: PMC3772741  PMID: 23711895
HIV; drug resistance mutations; naive patients; protease inhibitors; virological failure
4.  Impact of HIV-1 viral subtype on disease progression and response to antiretroviral therapy 
Our intention was to compare the rate of immunological progression prior to antiretroviral therapy (ART) and the virological response to ART in patients infected with subtype B and four non-B HIV-1 subtypes (A, C, D and the circulating recombinant form, CRF02-AG) in an ethnically diverse population of HIV-1-infected patients in south London.
A random sample of 861 HIV-1-infected patients attending HIV clinics at King's and St Thomas' hospitals' were subtyped using an in-house enzyme-linked immunoassay and env sequencing. Subtypes were compared on the rate of CD4 cell decline using a multi-level random effects model. Virological response to ART was compared using the time to virological suppression (< 400 copies/ml) and rate of virological rebound (> 400 copies/ml) following initial suppression.
Complete subtype and epidemiological data were available for 679 patients, of whom 357 (52.6%) were white and 230 (33.9%) were black African. Subtype B (n = 394) accounted for the majority of infections, followed by subtypes C (n = 125), A (n = 84), D (n = 51) and CRF02-AG (n = 25). There were no significant differences in rate of CD4 cell decline, initial response to highly active antiretroviral therapy and subsequent rate of virological rebound for subtypes B, A, C and CRF02-AG. However, a statistically significant four-fold faster rate of CD4 decline (after adjustment for gender, ethnicity and baseline CD4 count) was observed for subtype D. In addition, subtype D infections showed a higher rate of virological rebound at six months (70%) compared with subtypes B (45%, p = 0.02), A (35%, p = 0.004) and C (34%, p = 0.01)
This is the first study from an industrialized country to show a faster CD4 cell decline and higher rate of subsequent virological failure with subtype D infection. Further studies are needed to identify the molecular mechanisms responsible for the greater virulence of subtype D.
PMCID: PMC2827379  PMID: 20205896
5.  Comparison of Human Immunodeficiency Virus Type 1-Specific Inhibitory Activities in Saliva and Other Human Mucosal Fluids▿  
Clinical and Vaccine Immunology  2006;13(10):1111-1118.
Several human mucosal fluids are known to possess an innate ability to inhibit human immunodeficiency virus type 1 (HIV-1) infection and replication in vitro. This study compared the HIV-1 inhibitory activities of several mucosal fluids, whole, submandibular/sublingual (sm/sl), and parotid saliva, breast milk, colostrum, seminal plasma, and cervicovaginal secretions, from HIV-1-seronegative donors by using a 3-day microtiter infection assay. A wide range of HIV-1 inhibitory activity was exhibited in all mucosal fluids tested, with some donors exhibiting high levels of activity while others showed significantly lower levels. Colostrum, whole milk, and whole saliva possessed the highest levels of anti-HIV-1 activity, seminal fluid, cervicovaginal secretions, and sm/sl exhibited moderate levels, and parotid saliva consistently demonstrated the lowest levels of HIV-1 inhibition. Fast protein liquid chromatography gel filtration studies revealed the presence of at least three distinct peaks of inhibitory activity against HIV-1 in saliva and breast milk. Incubation of unfractionated and fractionated whole saliva with antibodies raised against human lactoferrin (hLf), secretory leukocyte protease inhibitor (SLPI), and, to a lesser extent, MG2 (high-molecular-weight mucinous glycoprotein) reduced the HIV-1 inhibitory activity significantly. The results suggest that hLf and SLPI are two key components responsible for HIV-1 inhibitory activity in different mucosal secretions. The variation in HIV inhibitory activity between the fluids and between individuals suggests that there may be major differences in susceptibility to HIV infection depending both on the individual and on the mucosal fluid involved.
PMCID: PMC1595323  PMID: 16928883
7.  Rubella Virus and Chronic Joint Disease: Is There an Association? 
Journal of Clinical Microbiology  1998;36(12):3524-3526.
Synovial fluid samples and/or biopsies from 79 patients with various chronic inflammatory joint diseases or traumatic joint injury were tested for rubella virus (RV) in order to confirm or refute results from other studies that suggested RV as a cause of chronic inflammatory joint disease. Sixty-eight of the 72 patients tested had RV antibodies. RV RNA was detected by reverse transcription-PCR in the synovial fluid cells from two patients. RV was also isolated by cell culture from the synovial fluid of one of these two patients. This patient was a 42-year-old female with common variable immune deficiency and Mycoplasma hominis arthritis, while the other was a 68-year-old female with rheumatoid arthritis. While these results fail to confirm that RV is associated with chronic inflammatory joint disease, they suggest that RV may persist within a joint and be reactivated when cell-mediated immunity is suppressed.
PMCID: PMC105233  PMID: 9817866

Results 1-7 (7)