B2M and Sepsis: Based on the fold changes, the degree of connectivity in PPI network, and appropriateness of the samples, six proteins were selected for further verification in 53 patients of non‐sepsis, 37 patients of sepsis, and 35 patients of septic shock, including serum apolipoproteinC3 (ApoC3), serpin family A member 1 (SERPINA1), vascular cell adhesion molecule 1 (VCAM1), beta‐2‐microglobulin (B2M), glutathione peroxidase 3 (GPX3), and apolipoprotein E (ApoE).