Figure 2.

CD38 positive immune suppressive cell types; T regs, Bregs, specific Nk cell type, and tumor cells in TME produce adenosine (ADO) resulting suppression of cytotoxic activity effector T cells. CD31+ T regs contribute to immune suppression with an unknown mechanism, while Bregs prompt IL-10 mediated inhibition of naïve T cell differentiation into Th1 and Th17 but promote Treg proliferation. It has also been established that senesce drives the expression of CD38 in macrophages and endothelial cells [34]. CD38 in activated NK cells upregulates the release of IFNγ and TNFα and promotes degranulation, albeit depletion of CD38+ NK cells within the tumor does not correlate with patient response to antiCD38 treatment.