OKT3, an anti-CD3 antibody mainly indicated for the treatment of acute organ transplant rejection, may also lead to severe CRS with increased serum levels of cytokines (e.g., TNF-α, IL-2, IL-6, and IFN-γ).54,55 Rituximab, a chimeric anti-CD20 mAb, is widely used to treat hematological malignancies, including CD20-positive diffuse large B-cell lymphoma and56 and chronic lymphocytic leukemia.57 Severe CRS has occurred in patients receiving rituximab, who had severe dyspnea, fever and blood pressure changes. This evidence concerns the gene IFNG and B-cell chronic lymphocytic leukemia.