Microarray analysis of HFMD. (A) Scatter plot of miRNA expression determined by miRNA microarray analysis. The expression profile of 1,887 miRNAs on a log2 scale in HFMD and in the control group is plotted. Red and green dots represent the number of miRNAs that were significantly (P < 0.05 and 1.5 fold-change cut-off) up-regulated and down-regulated, respectively, in HFMD, and black dots represent a lack of differential expression. (a) Comparison between normal controls and MHFMD samples, (b) comparison between normal controls and ESHFMD samples, and (c) comparison between MHFMD and ESHFMD samples. (B) Venn diagram illustrates the overlapping results of the differentially expressed miRNAs in MHFMD vs. control, ESHFMD vs. control, and MHFMD vs. ESHFMD comparisons. Circles include numbers of up-regulated or down-regulated human miRNAs of each pair-wise comparison. The 11 miRNAs in the centre of the Venn diagram represent miRNAs that are differentially expressed in all group comparisons. (C) Heat map analysis of differentially regulated miRNAs among ESHFMD, MHFMD, and control serum samples according to Venn diagram analysis. Heat map colours represent relative miRNA expression as indicated in the colour key. Red represents high expression, whereas green represents low expression.