In comparison to B-cell immunotherapies, the incidence and severity of infusion-related reaction (IRR)/cytokine release syndrome (CRS) using CD123-targeted immunotherapy may be more pronounced (96% IRR/CRS but only 8% Grade 3–4) due to the shared target antigen expression of monocytes and macrophages, which mediate IL-6 production [71]. This evidence concerns the gene IL3RA and congenital rubella syndrome.