IL6 and hand, foot and mouth disease: Further, post-hoc analysis using Bonferroni’s multiple comparison test found that serum levels of the inflammatory biomarkers dramatically increased approximately 3- to 8-times on average in the severe group in comparison with the mild group (all P < 0.001), while the protein levels of sera CRP, IL-6, IFN-γ and TNF-α in mild HFMD group were only one- to twofold higher as compared to health control group (all P < 0.05).