Analysis of potential circulating mediators of basophil activation [anti‐drug antibodies (ADA), basophil activation by MOv18 IgE ex vivo, soluble FRα, autoantibodies to FRα, total IgE and anti‐αGAL IgE] did not identify a possible association of markers in patients who experienced urticaria at any grade without systemic anaphylaxis (Table S4) versus those who did not experience urticaria (Table S5). Here, ADA is linked to urticaria.