ITIH4 and HIV infectious disease: Though clear differences were apparent in the PSGL-1:gp120 ratios of pseudoviruses and PBMC viruses produced in vitro, the fact that PSGL-1 was incorporated in all of the PBMC-produced virus isolates tested, including SIV strains, demonstrates the biological importance of PSGL-1 in HIV infection and also supports the idea that PSGL-1 may play a role in the pathogenicity of a many enveloped viruses [11, 13, 14].