In the Zuma-1 trial (cohort 3), patients were treated with prophylactic tocilizumab in combination with CART19 resulting in reduction in severe CRS, but there was a trend toward increased ICANS rates and severity thought to be due to peripheral IL-6 receptor blockade resulting in shunting of IL-6 to the CSF space and worsening CNS toxicity (36, 37). This evidence concerns the gene IL6 and congenital rubella syndrome.