Furthermore, in chimeric antigen receptor T-cell therapy, which, like bispecific T-cell engagers, engages cluster of differentiation 3 to activate T cells, a median peak IL-6 level of 8309 pg/mL has been reported in patients with grade 4 to 5 CRS, compared with 122 pg/mL in those with grade 1 to 3 CRS or no CRS.5 Here, IL6 is linked to congenital rubella syndrome.