TY - JOUR T1 - The role of CD74 in experimental and clinical acute lung injury JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P3927 AU - Guosheng Wu AU - Yu Sun AU - Xingtong Wang AU - Bing Ma AU - Zhaofan Xia Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P3927.abstract N2 - A soluble form of CD74 was recently discovered in autoimmune liver disease. With its ligand, macrophage migration inhibitory factor (MIF), they might be suitable candidates for evaluation as biomarkers of disease activity. As our previous study, consistent with others, has shown that MIF was highly expressed in acute lung injury (ALI), in present study, we investigated the existence of soluble form of CD74 in serum and bronchoalveolar lavage fluid (BALF) in lipopolysaccharide (LPS)-induced ALI mouse model and burn or trauma related ALI patients, preliminarily exploring the possibility of CD74 as a biomarker of ALI. We found that soluble CD74 did exist in serum from both patients and healthy people and its levels from ALI patients (n=67) were significantly higher than those from healthy controls (n=58). In ALI mouse model, similar results were obtained in serum. Furthermore, the soluble CD74 was also found in BALF and was obviously elevated in ALI group when compared with control group as well. Next, the expression of CD74 in lung tissue was significantly increased by Real-time PCR and Western blot after LPS induction in mouse model. In addition, the levels of soluble CD74 positively correlated with levels of IL-6, TNFα and MCP-1 in serum both from ALI patients and mouse model. In summary, our data provided the first evidence of existence of soluble CD74 both in serum and BALF from ALI patients and experimental model. Elevated soluble CD74 in serum and BALF of ALI might be released from lung parenchyma and was closely related to accepted inflammatory factors. These results raise the possibility that CD74 may play an important role in ALI and soluble CD74 may be a promising protein to be a biomarker of ALI. ER -