On day +22, after receiving CD22 CAR-T, cells revealed the development of IEC-associated hemophagocytic lymphohistiocytosis (HLH) due to an uptrend in LDH (4,106 μ/L), ferritin (>30,000 ng/mL), and other features determined by an HScore summarized in Table 1. This evidence concerns the gene CD22 and hemophagocytic syndrome.