CD4 and neoplasm: Treg cell reduction and blockade of tumor vascularization by REG alone did not persist when therapy was stopped, whereas REG + aPD1 induced durable effects, as demonstrated by the significant delay in tumor revascularization and Treg reinfiltration between day 14 and day 25 and the trend towards higher intratumoral levels of CD4+ and CD8+ T cells.