2.3 Analyses of cytokines in SFTS and COVID-19 patients
To characterize the effect of SFTSV and SARS-CoV-2 infection on the
production of serum cytokines in SFTS and COVID-19 patients, Interleukin
(IL)-2, IL-4, IL-6, IL-10, IL-17A, interferon-γ (IFN-γ), and tumour
necrosis factor (TNF-α) were measured using human Th1/Th2/Th17 CBA kits
(BD Bioscience, San Diego, CA) according to the manufacturer’s
instructions, with minor modifications. Sample acquisitions were
performed with a FACS Canto II flow cytometer and analysed by FCAP Array
software version 3.0 (BD Bioscience). All statistical analyses were
performed using SPSS 22.0 (SPSS, an IBM Company). TGF-β was measured in
the collected serum using a TGF-β-1 Human ELISA Kit (Thermo Fisher
Scientific) according to the manufacturer’s protocols.
To compare the mean difference between patients with fatal and nonfatal
SFTS disease and between patients with severe and critical and mild to
moderate COVID-19 disease, we usually used a two-sample t-test. When
using this method, we checked some assumptions, such as normality, equal
variance, and independence. When these assumptions were not met, we used
a nonparametric two-sample t-test called the Wilcoxon-Mann‒Whitney
test.[7] P values<0.05 indicated
statistical significance.