Above all, should PSGL-1 be established in the future as a critical marker during HIV infection, it is possible that the utilization of PBMCs for the profiling of PSGL-1 in low socio-economic settings may be easier and more practical, as PBMCs sampling is easier and isolation of CD4+ T-cells from PBMCs is not a procedure performed routinely in disadvantaged settings. The gene discussed is CD4; the disease is HIV infectious disease.