Browsing by Author "Cao, Huyen"

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    High T-cell immune activation and immune exhaustion among individuals with suboptimal CD4 recovery after 4 years of antiretroviral therapy in an African cohort
    (BMC infectious diseases, 2011) Nakanjako, Damalie; Ssewanyana, Isaac; Mayanja-Kizza, Harriet; Kiragga, Agnes; Manabe, Yukari C.; Nabatanzi, Rose; Kamya, Moses R.; Cao, Huyen
    Antiretroviral therapy (ART) partially corrects immune dysfunction associated with HIV infection. The levels of T-cell immune activation and exhaustion after long-term, suppressive ART and their correlation with CD4 T-cell count reconstitution among ART-treated patients in African cohorts have not been extensively evaluated.T-cell activation (CD38+HLA-DR+) and immune exhaustion (PD-1+) were measured in a prospective cohort of patients initiated on ART; 128 patient samples were evaluated and subcategorized by CD4 reconstitution after long-term suppressive treatment: Suboptimal [median CD4 count increase 129 (-43-199) cells/μl], N = 34 ], optimal [282 (200-415) cells/μl, N = 64] and super-optimal [528 (416-878) cells/μl, N = 30].Both CD4+ and CD8 T-cell activation was significantly higher among suboptimal CD4 T-cell responders compared to super-optimal responders. In a multivariate model, CD4+CD38+HLADR+ T-cells were associated with suboptimal CD4 reconstitution [AOR, 5.7 (95% CI, 1.4-23, P = 0.014)]. T-cell exhaustion (CD4+PD1+ and CD8+PD1+) was higher among suboptimal relative to optimal (P < 0.001) and super-optimal responders (P < 0.001). T-cell exhaustion was significantly associated with suboptimal responders [AOR, 1.5 (95%CI, 1.1-2.1), P = 0.022].T-cell activation and exhaustion persist among HIV-infected patients despite long-term, sustained HIV-RNA viral suppression. These immune abnormalities were associated with suboptimal CD4 reconstitution and their regulation may modify immune recovery among suboptimal responders to ART.
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    Immunologic Pathways That Predict Mortality in HIV-Infected Ugandans Initiating Antiretroviral Therapy
    (The Journal of infectious diseases, 2017) Lee, Sulggi; Byakwaga, Helen; Boum, Yap; Burdo, Tricia H.; Williams, Kenneth C.; Lederman, Michael M.; Huang, Yong; Tracy, Russell P.; Cao, Huyen; Haberer, Jessica E.; Kembabazi, Annet; Bangsberg, David R.; Martin, Jeffrey N.; Hunt, Peter W.
    The plasma kynurenine/tryptophan (KT) ratio, a marker of adaptive immune defects, strongly predicts mortality during treated human immunodeficiency virus (HIV) disease in Ugandans as compared to US-based populations. Here, the KT ratio and T-cell and plasma biomarkers of immune activation were measured among 535 HIV-infected Ugandans prior to ART initiation and at month 6 of viral suppression. The month 6 KT ratio (adjusted hazard ratio [aHR], 2.74), soluble CD14 level (aHR, 2.32), interleukin 6 level (aHR, 2.34), and D-dimer level (aHR, 1.95) were associated with mortality occurring ≥6 months after ART initiation. The KT ratio remained significantly predictive of mortality even after adjustment for the additional biomarkers, suggesting an independent contribution to clinical outcomes in resource-limited settings.
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    The Kynurenine Pathway of Tryptophan Catabolism, CD4+ T-Cell Recovery, and Mortality Among HIV-Infected Ugandans Initiating Antiretroviral Therapy
    (The Journal of infectious diseases, 2014) Byakwaga, Helen; Boum, Yap; Huang, Yong; Muzoora, Conrad; Kembabazi, Annet; Weiser, Sheri D.; Bennett, John; Cao, Huyen; Haberer, Jessica E.; Deeks, Steven G.; Bangsberg, David R.; McCune, Joseph M.; Martin, Jeffrey N.; Hunt, Peter W.
    Human immunodeficiency virus (HIV) infection–induced indoleamine 2,3-dioxygenase-1 (IDO) expression in activated monocytes and dendritic cells catabolizes tryptophan to kynurenine and other downstream catabolites that inhibit T-cell proliferation and interleukin 17 (IL-17) production. The prognostic significance of this pathway in treated HIV disease is unknown. We measured systemic IDO activity (calculated as the ratio of plasma levels of kynurenine to tryptophan; hereafter, the “KT ratio”) in HIV-infected Ugandans before and during antiretroviral therapy (ART)–mediated viral suppression and its association with the rate of subsequent CD4+ T-cell count recovery and mortality. Among 435 participants, a higher pre-ART KT ratio was associated with a higher plasma virus load (P < .001) and lipopolysaccharide level (P = .018), a lower CD4+ T-cell count (P < .001), and female sex (P = .047). Through month 12 of ART-mediated viral suppression, the plasma KT ratio decreased by approximately 50% (P < .001). After adjustment for pre-ART CD4+ T-cell count, virus load, age, and sex, a higher month 12 KT ratio predicted a slower rate of subsequent CD4+ T-cell count recovery (P = .001). Thirty-nine participants died. After adjustment for pre-ART CD4+ T-cell count, virus load, body mass index, sex, and age, a higher pre-ART and month 6 KT ratio predicted increased mortality (P ≤ .016). The kynurenine pathway of tryptophan catabolism independently predicts poor CD4+ T-cell count recovery and increased mortality among HIV-infected Ugandans initiating ART and may be an important target for interventions.
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    Short-Term Risk of HIV-Disease Progression and Death in Ugandan Children Not Eligible for Antiretroviral Therapy
    (Journal of acquired immune deficiency syndromes, 2010) Charlebois, Edwin D; Ruel, Theodore D; Gasasira, Anne F.; Achan, Jane; Kateera, Frederick; Akello, Caroline; Cao, Huyen; Dorsey, Grant; Rosenthal, Philip J; Ssewanyana, Isaac; Kamya, Moses R; Havlir, Diane V
    Background—Increasing numbers of HIV-infected children not yet eligible for antiretroviral therapy (ART) are entering health care in Africa. We sought to characterize the risk of short-term disease progression in this population. Methods—In a cohort of HIV-infected ART-naive and -ineligible Ugandan children >1 year old, the rates of clinical/immunologic progression within 2 years were assessed using Kaplan–Meier survival analysis and multivariate Cox proportional-hazards modeling. Results—Among 192 children (mean age: 6.4 years, CD4%:25), 19% progressed within 2 years by WHO-stage 3/4 event(n=22), death (n=3), or WHO-defined CD4 threshold for ARTinitiation( n=12). Significant univariate predictors were CD4%(HR=2.0 per 10% decrease, p=0.005), HIV-RNA level(HR=2.4 per log10 increase, p=0.002), male gender (HR:2.0, p=0.04), age < 3 years (HR=3.7, p=0.001), CD4-activation [%CD4+CD38+HLADR+] (HR=1.6 per 10% increase, p=0.05) and CD8-activation [%CD8+CD38+HLADR+](HR=1.3 per 10% increase, p=0.05] (HR=1.3, p=0.5). In multivariate analysis, CD4%(HR=2.0, p=0.034), HIV-RNA level(HR=1.8, p=0.013) and age < 3 years (HR:3.0, p=0.008) were independently predictive. Children with HIV-RNA >105 copies/ml and CD4% <25 had progression rates of 29% (1 year) and 34% (2 years). Conclusions—Even with frequent CD4 monitoring, HIV-infected Ugandan children experienced significant clinical events while ineligible for ART. Alternate strategies for monitoring or ART-initiation may be needed to improve outcomes