ResultsA/A genotype carriers were two times more likely to develop in newborns with lung disease under homozygote (A/A vs. G/G: OR = 2.66, 95%CI = 1.03-6.87, p = 0.039) and recessive (A/A vs. G/G-A/G: OR = 2.42, 95%CI = 1.07-6.06, p = 0.047) models. Also, a higher frequency of A/A genotype was observed in the patient's cohort complicated with sepsis (44.2 vs. 14.3%, p = 0.002). Neonates with lung disease with A variant had more risk for developing sepsis under homozygote (A/A vs. G/G: OR = 5.19, 95%CI = 1.73-15.6, p = 0.002), dominant (A/G-A/A vs. G/G: OR = 2.39, 95%CI = 1.02-5.58, p = 0.041), and recessive (A/A vs. G/G-A/G: OR = 5.38, 95%CI = 1.86-15.5, p < 0.001) models. Regression analysis revealed rs4926*A/A genotype as an independent predictor risk factor for sepsis development in cohorts with lung disease (adjusted OR = 4.26, 95%CI = 1.38-13.1, p = 0.012). The circulatory transcript was significantly downregulated in neonates with lung disease in whom rs4926*A/A carriers had the least expression levels (median: −2.86, IQR: −3.55 to −1.71; p < 0.001). ROC curve analysis revealed C1INH expression could differentiate between cohorts with/without subsequent development of sepsis, and the discrimination ability was enhanced when combined with circulatory IL-6 and CRP levels (AUC = 0.926, 95%CI = 0.87-0.97).