Here, we unprecedently show that CD4 + T cells are present in primary eBL tumor tissues and that CD4 + T cells on the one hand kill pre-eBL cells in vitro and on the other hand can initiate crucial EBV Latency III to Latency I switch, which supposedly takes place early in eBL development, supporting the survival of EBV-infected pre-eBL cells by lowering their immune recognition. This evidence concerns the gene CD4 and neoplasm.