NPPB and congenital rubella syndrome: Severe CRS, fever, and increase in NT‐proBNP (grade 3) were observed in Patient 06 with 6.2 × 107/kg BCMA‐CART, while severe fever (grade 4), increase in NT‐proBNP (grade 3), CRS (grade 2), and CRES (grade 1) emerged in Patient 08 with 6.8 × 107/kg BCMA‐CART (Table S2).