Browsing by Author "Yirrell, David"

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    Effect of Human Immunodeficiency Virus (HIV) Type 1 Envelope Subtypes A and D on Disease Progression in a Large Cohort of HIV-1–Positive Persons in Uganda
    (The Journal of Infectious Diseases, 2002) Kaleebu, Pontiano; French, Neil; Mahe, Cedric; Yirrell, David; Watera, Christine; Lyagoba, Fred; Nakiyingi, Jessica; Rutebemberwa, Alleluiah; Morgan, Dilys; Weber, Jonathan; Gilks, Charles; Whitworth, Jimmy
    The effect of human immunodeficiency virus (HIV) type 1 envelope subtypes A and D on disease progression was investigated in 1045 adults in Uganda. At enrollment and every 6 months, a clinical history, examination, and laboratory investigations that included CD4 cell counts were done. HIV-1 envelope subtype was assessed mainly by peptide serology supplemented by heteroduplex mobility assay and DNA sequencing. A multivariate analysis of survival was performed to assess the prognostic value of HIV-1 subtype on death. A marginal general linear model also determined the effect of subtype on CD4 cell count during follow-up. Subtype D was associated with faster progression to death (relative risk, 1.29; 95% confidence interval, 1.07–1.56; P ¼ .009) and with a lower CD4 cell count during follow-up (P ¼ .001), compared with subtype A, after adjusting for CD4 cell count at enrollment. In Africa, envelope subtype D is associated with faster disease progression, compared with subtype A
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    The Relationship between HIV Type 1 Disease Progression and V3 Serotype in a Rural Ugandan Cohort
    (AIDS Research & Human Retroviruses, 2004) Senkaali, David; Muwonge, Richard; Morgan, Dilys; Yirrell, David; Whitworth, James; Kaleebu, Pontiano
    Antigenic properties of the V3 region are reflected by HIV-1 serotypes. These may represent biological properties of the virus. We serotyped HIV-1 in 142 serum samples from participants in a rural Uganda cohort who seroconverted between August 1991 and December 2001. Clinical progression was assessed using Cox proportional hazards and Kaplan–Meier methods. Of 112 (79%) samples successfully serotyped, 36% were serotype A, 17% serotype B, 18% serotype C, and 29% serotype D. Median follow-up time, age at enrollment, and first CD4 count were similar in each serotype group. Clinical progression was faster for serotype D than other serotypes to AIDS or death, death, and CD4 count <200 cells/mm3 (all p < 0.05). HIV-1 V3 serotypes are associated with variations in the pathogenicity of HIV-1 and should be taken into account when studying the biological relevance of HIV-1 diversity.