FOLR1 and anaphylaxis: 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).