Anti-CD36 Antibody Induces Transfusion-related Acute Lung Injury In Mice And The Underlying Mechanisms

ObjectiveTransfusion-related acute lung injury(TRALI)refers to an acute lung injury that develops during or within 6 hours after a transfusion of blood products.It is characterized by acute hypoxemia and non-cardiogenic pulmonary edema.TRALI can induced by all plasma-containing blood products,including whole blood,frozen plasma,fresh frozen plasma and platelets.In the current reports,TRALI's mortality is about 5%-35%.It has emerged as the leading cause of fatalities in transfusion-related diseases.The factors that can induce TRALI are generally divided into non-immune and immune ones.Non-immune factors include biologically active lipids,CD40L etc,while immune ones are refered to anti-HLA,anti-HNA antibodies in the blood products.The anti-CD36 antibody was first identified in 2008 as a new antibody that induces TRALI in human.CD36 belongs to the type B scavenger receptor family,which is located on the surface of many types of cells.There is a certain rate of mutation in the gene of CD36,leading to the protein phenotype deficiency.Individuals with type I deficiency(neither platelets nor monocytes express CD36)may produce anti-CD36 antibody when they are getting immuned by chance.The frequency of CD36 deficiency is higher in Asians and Africans(3%-4%),so there is a higher risk of getting TRALI in these people while the normal individuals transfusing blood product contained CD36 antibodies.Therefore,it is important for us to study the pathogenesis of anti-CD36 induced TRALI.Animal models are the mostly used method to study TRALI for researchers.At present,animal models of anti-HLA class I and anti-HNA antibodies induced TRALI have been established,and the pathological mechanism has been studied to some extent.Anti-CD36 IgG2a monoclonal antibody was obtained from hybridoma cells stably,We established the anti-CD36 antibody induced TRALI mouse model by injecting the antibodies into the C57BL/6 mice with CD36 gene knockout and the wild type mice,and the pathogenesis was preliminarily studied and discussed.MethodsFor the mouse model establishment:we injected the monoclonal mouse anti-CD36 mouse antibody which screened by ourself into CD36+/+C57BL/6 male mice by tail vein,then observed the reaction of the mice to the antibody,measured the rectal temperature,arterial blood pressure,SO2%,lung wet/dry ratio,protein concentration of the BALF and the amount of cytokines.For the mechanism of TRALI:we degested the antibody by pepsin to gain the F(ab')2 fragments.Then we injected the fragments into the mice to see whether TRALI still happened.Besides,we used GdCl3 to deplete the monocytes in the peripheral blood,and to see whether 32-106 can still induce TRALI without monocytes.Results1.Transfusion of 32-106 reduced the rectal temperature of CD36+/+male mice,increased their mortality,downregulated their arterial blood pressure and SO2%,caused lung edema and the lung histology got pathological changed.Compared with the control group,the differences were statistically significant.2.The protein concentration of BALF was increased with 32-106 injection.MIP-2,KC and TNF-? were upregulated according to the 32-106 treatment.3.F(ab')2 fragments of 32-106 couldn't induce TRALI.4.Monocyte depletion with GdCl3 treatment abrogates TRALI in C57BL/6 mice.Conclusion1.Anti-CD36 antibody can induce TRALI in CD36+/+C57BL/6 mice.2.32-106 induces TRALI in a Fc-dependent way.3.Monocytes are involved in the TRALI development,while they are depleted,TRALI could not initiate.