IL1B and hand, foot and mouth disease: As shown in Fig. 1, the results of ANCOVA analysis displayed that there were statistically significant differences between the healthy group, the mild and severe HFMD groups in terms of CRP (F = 138.5, P < 0.001), IL-1β (F = 361.4, P < 0.001), IL-6 (F = 276.1, P < 0.001), IFN-γ (F = 730.9, P < 0.001) and TNF-α (F = 832.4, P < 0.001).