PD-L1 Expression Induced by the 2009 Pandemic Influenza A(H1N1) Virus Impairs the Human T Cell Response

Figure 4

PD-L1 expression is increased on dendritic cells and T cells from PBMCs of patients with acute influenza infection. Cell proportions and surface PD-L1 expression on cDCs and pDCs (a–d) and CD4⁺ and CD8⁺ T cells (e–h) from cryopreserved PBMCs from patients with confirmed infection with A(H1N1)pdm09 virus (pH1N1+), patients with influenza-like illness but with a negative RT-PCR result for pandemic H1N1 influenza (pH1N1−), and healthy controls (HC, 𝑛=10; error bars indicate SEM) were analyzed by flow cytometry. MFI: mean fluorescence intensity; pH1N1: A(H1N1)pdm09 virus. *𝑃<0.05, **𝑃<0.01, and ***𝑃<0.001 (Mann-Whitney test).

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