To improve the effectiveness exerted by mRNA vaccines targeting monoantigens, Lichtenegger et al. performed the first-in-human phase I trial involving 10 AML patients on TLR7/8-matured DC-pulsed mRNA vaccines encoding WT1 and PRAME (two AML-associated antigens) as well as CMV pp65.184 Seven patients were subjected to the complete regular 10 vaccinations, resulting in an increase in WT1 (2/10)-, PRAME (4/10)-, and CMV pp65 (9/10)-specific CD8+ T cells, and CMV pp65-induced CD4+ T cells (4/7) in the peripheral blood. The gene discussed is CD4; the disease is acute myeloid leukemia.