In patients with anaphylactic shock to bee venom immunotherapy, intravascular coagulation and diminution of plasma HK has been reported (25) and the sting-challenge test in patients with sting-induced anaphylaxis has been described to promote the generation of FXIIa-C1INH and kallikrein-C1INH complexes, as well as cleavage of HK (24). This evidence concerns the gene SERPING1 and anaphylaxis.