This episode digs into the pathophysiology of urticaria vasculitis from anti-C1q to the story of bradykinin. ·       Intro 0:11 ·       In this episode 0:22 ·       Review of episode 83 1:23 ·       Listen to previous episode, The Complement System for Dunces 4:09 ·       Anti-C1q antibodies 6:26 ·       Lupus, anti-C1q and lupus nephritis 9:33 ·       What happens when you inject anti-C1q in a mouse? 12:56 ·       The allergy component: anti-C1q, urticaria and angioedema 17:36 ·       Bradykinin-mediated angioedema and C1q deficiency 24:20 ·       What is the kinin kallikrein system? 26:21 ·       French researchers in 1909: human urine injected in dogs 27:30 ·       How is this relevant to urticarial vasculitis? 31:08 ·       SERPING1 gene mutation 31:23 ·       Summary 32:06 ·       COPD association with urticarial vasculitis 33:51 ·       Coming up in episode 85 35:28 ·       Thanks for listening 35:45 Disclosures: Brown reports no relevant financial disclosures. We’d love to hear from you! Send your comments/questions to Dr. Brown at [email protected]. Follow us on Twitter @HRheuminations @AdamJBrownMD @HealioRheum. References: Busse P, et al. J Allergy Clin Immunol Pract. 2022;doi:10.1016/j.jaip.2021.11.011. Davis MDP, et al. J Allergy Clin Immunol Pract. 2018;doi:10.1016/j.jaip.2018.05.006. Dorn JM, et al. Ann Allergy Asthma Immunol. 2023;doi:10.1016/j.anai.2023.06.014. Marzano AV, et al. J Allergy Clin Immunol. 2022;doi:10.1016/j.jaci.2022.02.007. Siegert CE, et al. Clin Immunol Immunopathol. 1993;doi:10.1006/clin.1993.1066. Stojan G, et al. Lupus. 2016;doi:10.1177/0961203316645205. Venzor J, et al. Clin Rev Allergy Immunol. 2002;doi:10.1385/CRIAI:23:2:201. Wisnieski JJ, et al. Medicine. 1995;doi:10.1097/00005792-199501000-00003.