Fortunately, IL-6 inhibition does not impair efficacy.96 CAR T-cell-related encephalopathy (CRES), more recently known as immune effector cell-associated neurotoxicity syndrome (ICANS), is another potential side effect of CAR T therapy seen in 40% of patients.97 ICANS normally develops simultaneously with or after CRS. This evidence concerns the gene IL6 and congenital rubella syndrome.