To explore the distribution of different CRS grades, in 2017, Hay et al. reported data for 133 adult patients who received CD19 CAR-T cells.34 According to the consensus classification criteria of CRS grade proposed by Lee and his colleagues,35 they found that CRS developed in 70% patients, including 62.5% with grade 1~3 CRS and 7.6% with grade 4~5 CRS. This evidence concerns the gene CD19 and congenital rubella syndrome.