Previous studies in patients with cutaneous T-cell lymphoma (CTCL) [13,34], chronic lymphocytic leukemia (CLL) [35], CD25-expressing lymphomas [36], and melanoma [33] have identified anti-diphtheria toxin antibodies in a modest number of patients at baseline, with most patients developing these antibodies after treatment [13,33,34,35,36]. Here, IL2RA is linked to B-cell chronic lymphocytic leukemia.