The peak serum IL-6 level was significantly higher in patients with grade 2–4 CRS than in those with grade 0–1 CRS (Figure 3A); however, serum ferritin levels and CD22 and CD19 CAR T cell infusion doses did not differ between patients with grade 2–4 CRS and those with 0–1 CRS (Figures 3B–D). This evidence concerns the gene IL6 and congenital rubella syndrome.