The value of Heparin-binding protein in bronchoalveolar lavage fluid in ARDS：a case control study

Background: Heparin-binding protein (HBP) play an important role in ARDS. Plasma HBP is a good biomarker on predicting ARDS, but the value of bronchoalveolar lavage fluid (BALF) HBP in ARDS has not been studied. Methods We use cecum ligation and puncture (CLP) to induce ARDS model in mice and study plasma HBP, BALF HBP and lung injury severity, lung wet/dry ratio and total protein levels in BALF. Also we included a total of 44 patients with ARDS and 38 patients with cardiogenic pulmonary edema (CPE). We compared BALF and plasma HBP levels between the two groups and studied their correlation. Results Animal study show, compare with sham group, CLP group mice show significant higher lung WD Ratio(P = 0.002), BALF protein(P < 0.001), BALF HBP(P = 0.013) and plasma HBP(P = 0.003) than sham group. Lung injury index WD Ratio and BALF protein have significant correlation with plasma HBP and BALF HBP in CLP group mice. Plasma and BALF HBP also have significant correlation (P = 0.026). Study in patients showed there are significant difference in BALF HBP (P < 0.001), BALF Protein (P < 0.001) and Plasma HBP (P < 0.001) between ARDS and CPE patients. There are significant correlation between P/F ratio and BALF HBP(P = 0.005) and plasma HBP(P = 0.021).We also found a strong correlation between BALF HBP and plasma HBP levels (P < 0.001). Conclusions Our study suggests that both in animal or human, Both BALF and Plasma HBP were significantly increased during lung injury, and were significantly correlated with the severity of lung injury, while BALF was better correlated with lung injury. BALF is associated with elevated plasma HBP levels. BALF HBP could be used as a biomarker to guide the diagnosis and treatment of ARDS.