CPI-637 could not obviously decrease the HIV-1 p24 expression in PBMCs, indicating that it might not clearly reduce the risk of reactivated HIV-1 infection in bystander cells even though it downregulated the expression of a CD4 receptor/coreceptor (CCR5 and CXCR4) on the surface of PBMCs (Data not shown). This evidence concerns the gene CD4 and HIV-1 infection.