CD33 and acute myeloid leukemia: In addition, there are side effects, both common to conventional AML management strategies, such as high rates of opportunistic and nosocomial infections due to cytopenia [38,39,40], and those related to specific targets, such as veno-occlusive disease, due to the expression of CD33 on hepatic Kupffer cells, observed also in patients treated with Gemtuzumab Ozogamicin [41], and cytokine release syndrome (CRS), due to activation of bystander immune cells and non-immune cells, such as endothelial cells, after binding the target antigen [42].