An additional limitation of the study is the lack of available data on the mutation status in the TP53 gene and other important genetic markers (e.g., del17p, NOTCH1 mutations, SF3B1), which may affect both the degree of immunosuppression and susceptibility to EBV reactivation in patients with CLL. The gene discussed is NOTCH1; the disease is B-cell chronic lymphocytic leukemia.