Reduced cellular immune function in patients after liver transplantation easily results in many types of viral infections,such as Epstein-Barr virus.Epstein-Barr virus is a γ-herpesvirus and is related to many malignant diseases,especially epithelial and lymph tumors.The abnormal interaction of cluster of differentiation 40 with cluster of differentiation 40 ligand and expression of cluster of differentiation 40 ligand are considered closely related to the development of myeloma cells.This study explored the influence and mechanism of Epstein-Barr virus infection on the phenotype and biological behavior of myeloma cells after liver transplantation.Flow cytometry was used to detect coexpression of cluster of differentiation 40 and cluster of differentiation 40 ligand in 10 samples of freshly isolated multiple myeloma cells.Cluster of differentiation 40 and cluster of differentiation 40 ligand were coexpressed in sample Nos.5,8,9,and 10,particularly in sample No.5.Western blot analysis was used to detect the expression of the Epstein-Barr virus antigens latent membrane protein 1 and Epstein-Barr virus nuclear antigen 2 in the multiple myeloma cell line RPMI 8226 infected with Epstein-Barr virus.The antigen expression indicated that Epstein-Barr virus can infect multiple myeloma virus cells in vitro.Reverse transcription-polymerase chain reaction revealed upregulated expression of cluster of differentiation 40 ligand on the infected RPMI 8226 cells,which may be involved in the anti-apoptosis activity of the infected cells.Confocal microscopy showed that pairs of molecules of cluster of differentiation 40,cluster of differentiation 40 ligand,and latent membrane protein 1 were colocalized on the surface of the infected cells.CXC chemokine receptor 4 was upregulated on the RPMI 8226 cells after Epstein-Barr virus infection.The migratory ability of the infected cells improved in the presence of the chemokine stromal cell-derived factor-1α.Anti-apoptosis and migration are known important biological characteristics of malignant cells.Our results indicate the involvement of Epstein-Barr virus in the origin and development of multiple myeloma.The risk of multiple myeloma increases when Epstein-Barr virus infects B cells in the germinal center,which may result in an anti-apoptosis effect of B cells and an improved ability to migrate from the germinal center to peripheral blood. Reduced cellular immune function in patients after liver transplantation easily results in many types of viral infections, such as Epstein-Barr virus. Epstein-Barr virus is a γ-herpesvirus and is related to many malignant diseases, especially epithelial and lymph tumors. interaction of cluster of differentiation 40 with cluster of differentiation 40 ligand and expression of cluster of differentiation 40 ligand are considered closely related to the development of myeloma cells. This study explored the influence and mechanism of Epstein-Barr virus infection on the phenotype and biological behavior of myeloma cells after liver transplantation. Flow cytometry was used to detect coexpression of cluster of differentiation 40 and cluster of differentiation 40 ligand in 10 samples of freshly isolated multiple myeloma cells. Cluster of differentiation 40 and cluster of differentiation 40 ligand were coexpressed in sample Nos .5, 8, 9, and 10, particularly in sample No. 5. Western blot analysis was used to detect the expression of the Epstein-Barr virus antigens latent membrane protein 1 and Epstein-Barr virus nuclear antigen 2 in the multiple myeloma cell line RPMI 8226 infected with Epstein-Barr virus. The antigen expression indicated that Epstein-Barr virus can infect multiple myeloma virus cells in vitro. Reverse transcription-polymerase chain reaction revealed regulated expression of cluster of differentiation 40 ligand on the infected RPMI 8226 cells, which may be involved in the anti-apoptosis activity of the infected cells. Confocal microscopy showed that pairs of molecules of cluster of differentiation 40, cluster of differentiation 40 ligand, and latent membrane protein 1 were colocalized on the surface of the infected cells. CXC chemokine receptor 4 was upregulated on the RPMI 8226 cells after Epstein-Barr virus infection. of the infected cells improved in the presence of the chemokine stromal cell-derived factor-1α. Anti-apoptosis and migration are known important biological characteristics of malignant cells. Your results indicate the involvement of Epstein-Barr virus in the origin and development of multiple myeloma. risk of multiple myeloma increases when Epstein-Barr virus infects B cells in the germinal center, which may result in an anti-apoptosis effect of B cells and an improved ability to migrate from the germinal center to peripheral blood.