For instance, aggregation has been linked with induction of allergic responses, including severe type 1 hypersensitivity responses, such as urticaria (wheals, sometimes accompanied by angioedema),11,12 or even anaphylaxis.13,14 Moreover, the aggregation of protein therapeutics has been shown to induce anti-drug antibodies (ADAs).15–17 ADAs can greatly reduce the efficacy of the therapeutic in two crucial ways. Here, AGPS is linked to anaphylaxis.