The results revealed that in comparison with the PBS group, the PPD induration and EC erythema groups contained more DEPs, among which various acute-phase proteins, including binding globin (Hp), ceruloplasmin (CER), SAA, complement C3, C5, etc., presented significantly increased levels, indicating that PPD and EC injection formed an active inflammatory environment in the skin. The gene discussed is C5; the disease is Erythema.