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CASE REPORT article

Front. Pediatr.
Sec. Pediatric Immunology
Volume 13 - 2025 | doi: 10.3389/fped.2025.1507727

Atypical hemolytic uremic syndrome with a C3 variant following COVID-19: a case report

Provisionally accepted
Masato Ando Masato Ando 1Kazuo Kubota Kazuo Kubota 1*Saori Kadowaki Saori Kadowaki 1Minako Kawamoto Minako Kawamoto 1Norio Kawamoto Norio Kawamoto 1Haruka Okamoto Haruka Okamoto 2SOICHIRO NAGAYA SOICHIRO NAGAYA 2Yuki Miwa Yuki Miwa 1Hidenori Ohnishi Hidenori Ohnishi 1
  • 1 Graduate School of Medicine, Gifu University, Gifu, Japan
  • 2 Gifu University Advanced Critical Care Center, Gifu, Japan

The final, formatted version of the article will be published soon.

    Atypical hemolytic uremic syndrome (aHUS) is a form of thrombotic microangiopathy (TMA) 13 characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute 14 kidney injury, and is caused by overactivation of the alternative complement pathway. A 13-year-old 15 Japanese boy with an unremarkable medical history developed symptoms of TMA following 16 coronavirus disease 2019 (COVID-19) infection with mild respiratory symptoms. He was eventually 17 diagnosed with aHUS with a gain-of-function C3 variant. He improved with supportive therapy and 18 plasma exchange, and did not require anti-C5 antibody therapy. In the literature, more than 20 cases 19 of de novo or relapsed aHUS have been described following COVID-19. It has been shown that the 20 complement lectin pathway can be activated by the severe acute respiratory syndrome coronavirus 2 21 (SARS-CoV-2) spike and N proteins, and the alternative pathway can be activated by the SARS-22 CoV-2 spike protein. The current case highlights the possibility that COVID-19, even when 23 respiratory symptoms are not severe, can trigger aHUS. 24

    Keywords: Atypical hemolytic uremic syndrome, GOF C3 variant, severe acute respiratory syndrome 9 coronavirus 2, Alternative complement pathway, inborn errors of immunity 10

    Received: 08 Oct 2024; Accepted: 07 Jan 2025.

    Copyright: © 2025 Ando, Kubota, Kadowaki, Kawamoto, Kawamoto, Okamoto, NAGAYA, Miwa and Ohnishi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Kazuo Kubota, Graduate School of Medicine, Gifu University, Gifu, Japan

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