The serum protein profiles in samples. (a) We used iTRAQ gel-free proteomics to determine the relative intensities of serum proteins. Only 101 proteins with an average variation larger than 1.25-fold were presented in this heat map. (b) The FC and KD subjects were subjected to drawing blood after evident diagnosis and before treatment. Among these varied proteins, S100A8, A9 and A12 were selected for further ELISA validation owing to their inflammatory roles56. DEFA1, PRDX2 and ORM1 were also included, since they were linked to the GO functions (Table 2) and their abundance tendencies were reproducible for the two pooled FC and two pooled KD serum samples. *, **, *** and **** denoted p-values < 0.05, 0.01, 0.001 and 0.0001 according to t-tests, respectively.