Browsing by Author "Ahmed, Aabid"

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    Disease Progression in Children With Perinatal Human Immunodeficiency Virus Correlates With Increased PD-1+ CD8 T Cells That Coexpress Multiple Immune Checkpoints
    (Oxford University Press, 2021) Tailor, Janki; Foldi, Julia; Generoso, Matthew; McCarty, Bret; Alankar, Aparna; Kilberg, Max; Mwamzuka, Mussa; Marshed, Fatma; Ahmed, Aabid; Liu, Mengling; Borkowsky, William; Unutmaz, Derya; Khaitan, Alka; Pediatrics, School of Medicine
    Background: PD-1 marks exhausted T cells, with weak effector functions. Adults living with human immunodeficiency virus (HIV) have increased levels of PD-1+ CD8 T cells that correlate with HIV disease progression, yet little is known about the role of PD-1+ CD8 T cells in children with perinatal HIV. Methods: We enrolled 76 Kenyan children with perinatal HIV and 43 children who were HIV unexposed and quantified PD-1 levels on CD8 T cells; their coexpression with immune checkpoints (ICs) 2B4, CD160, and TIM3; correlates with immune activation and HIV disease progression; and HIV-specific and -nonspecific proliferative responses. Results: PD-1+ CD8 T-cell frequencies are elevated in children with perinatal HIV and associated with disease progression. The majority of PD-1+ CD8 T cells coexpress additional ICs. ART initiation lowers total PD-1 levels and coexpression of multiple ICs. The frequency of PD-1+2B4+CD160+TIM3- in PD-1+ CD8 T cells predicts weaker HIV-specific proliferative responses, suggesting that this subset is functionally exhausted. Conclusions: Children with perinatal HIV have high levels of PD-1+ CD8 T cells that are a heterogeneous population differentially coexpressing multiple ICs. Understanding the complex interplay of ICs is essential to guide the development of PD-1-directed immunotherapies for pediatric HIV remission and cure.
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    High soluble CD163 levels correlate with disease progression and inflammation in Kenyan children with perinatal HIV-infection
    (Wolters Kluwer, 2020-01) Generoso, Matthew; Álvarez, Patricia; Kravietz, Adam; Mwamzuka, Mussa; Marshed, Fatma; Ahmed, Aabid; Khaitan, Alka; Pediatrics, School of Medicine
    Objectives: CD163 is a hemoglobin scavenger receptor on monocytes and macrophages, cleaved to soluble CD163 (sCD163) in the plasma following activation. In HIV+ adults, sCD163 is linked to non-AIDS morbidity and predicts mortality, but there is limited data in children. We investigated sCD163 levels in HIV+ children and their correlations with disease progression, immune activation and gut mucosal damage. Design and methods: We quantified sCD163 levels in Kenyan children aged 0–20 years with perinatal HIV infection, including 74 antiretroviral treatment (ART)-naïve (ART−) and 64 virally suppressed on ART (ART+), and 79 HIV unexposed-uninfected controls (HIV−). The cohort was divided into age groups 0–5 (younger) and 5–20 (older) years. Correlations between sCD163 and HIV viral load, %CD8+, CD4+ : CD8+ ratio, markers of T-cell activation and proliferation, and gut mucosal damage were also assessed. Results: ART− children have higher sCD163 levels compared with HIV− and ART+ children (P ≤ 0.01); ART+ have equivalent sCD163 levels to HIV− children. In a prospective analysis, sCD163 levels decreased in older ART− children after 12 months of treatment (P < 0.0001). Regardless of age, sCD163 levels correlate with clinical disease progression measured by %CD4+ T cells, CD4+ : CD8+ T-cell ratios and HIV viral load. sCD163 levels directly correlate with T-cell activation markers CD38, human leukocyte antigen-DR isotype, and Ki67 (P ≤ 0.01). Conclusion: High plasma sCD163 levels in HIV+ children correlate with advancing disease and T-cell activation. ART initiation normalizes sCD163 levels and may alleviate HIV-related morbidities and improve long-term pediatric outcomes.