Figure 2

TAMs express classical and non classical MHC class I. The classic MHC class I HLA A, HLA B and HLA C can interact with ILT2 and ILT4 receptors on the myeloid cells with a different strength in relation to the HLA polymorphisms and conformation negatively conditioning the level of myeloid activation. HLA A, B and C inhibits NK and T cell function through the interaction with the inhibitory Killer cell immunoglobulin-like receptor KIR3DL1/2 and KIR2DL1/2/3 respectively. The non classical MHC-I, HLA-G, can link KIR2DL4 on a minority of NK cells resulting in the cytokine and chemokine secretion with a pro-angiogenic purpose. The non classical HLA E recognizes CD94/NKG2A on NK cells triggering the production of the immune-suppressive cytokines IL-10 and TGF-beta by NK cells as well as protecting TAMs by NK and CTL dependent lysis.