In recent years, most host-derived tests for bacterial infections focused on peptide-based biomarkers have been applied to clinical practice, such as C-reactive protein (CRP), procalcitonin (PCT), tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), protein-10 (IP-10) and a combination of these biomarkers [48–50]. The gene discussed is CXCL10; the disease is bacterial infectious disease.