Changes and role of CD74 and CXCL9 positive macrophage subsets in rejection of rat liver transplantation.

Objective To explore the classification and changes of macrophage subsets in liver transplant rejection. Methods Rat liver transplantation model were established and divided into immune tolerance group (B-B), where the liver of BN rat donors was transplanted to BN rat recipients, and immune rejection group (L-B), in which the liver of Lewis rat donors was transplanted to BN rat recipients. Single-cell RNA sequencing and highthroughput RNA sequencing were used to distinguish the macrophage subsets of rat liver transplantation, and to find differential gene in rejection reactions. Immunohistochemistry was used to determine the changes and distribution of protein expression and cell subsets. Results CD68 positive macrophages were higher in the rejection group than that in the tolerance group (P < 0.05), and macrophages could be divided into 9 subsets. During the rejection reaction, the CXC chemokine ligand 9 (CXCL9) in the 8th subsets of macrophages was significantly increased, while the gene for white blood cell differentiation antigen 74 (CD74) in the 5th subsets was significantly increased (P < 0.05). CD74 ranked first in the differential gene synthesis of macrophages during rejection, followed by CXCL9. Compared with the tolerance group, a large number of CD74 positive macrophages were observed in the hepatic portal area of the rejection group, and the infiltration of CD74 positive macrophages in the hepatic sinuses was also significantly increased (P < 0.05), while a large number of CXCL9 positive macrophages were observed in the hepatic portal area and hepatic sinuses of the rejection group, especially in the portal area (P < 0.05), and CD14 positive cells were significantly increased (P < 0.05). Conclusions The CD74 positive macrophage subsets and CXCL9 positive macrophage subsets may be key subgroups in promoting liver transplant rejection, improving the mechanism of macrophage action in liver transplant rejection. [ABSTRACT FROM AUTHOR]