In the six patients with grade 3‐4 CRS, the median copies of anti‐CD19 and anti‐CD20 CAR were 65 680 and 23 715 copies/100 ng total DNA, respectively, which were not significantly different from those with grade 1‐2 CRS (n = 15) (Figure 4D‐I). The gene discussed is CD19; the disease is congenital rubella syndrome.