{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T14:29:45Z","timestamp":1781620185474,"version":"3.54.5"},"reference-count":16,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T00:00:00Z","timestamp":1774915200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:p>Thrombotic microangiopathy (TMA) after kidney transplantation presents a significant diagnostic and therapeutic challenge. Complement-mediated thrombotic microangiopathy (CM-TMA), caused by dysregulation of the alternative complement pathway, is frequently associated with predisposing variants in complement-regulatory genes but typically requires additional triggers for clinical manifestation. Ravulizumab, a long-acting terminal complement inhibitor, has demonstrated efficacy in native kidney disease, but data in transplant recipients remain limited. We present a 75-year-old kidney transplant recipient in whom previously unrecognized CM-TMA was triggered by COVID-19 infection and successfully treated with ravulizumab. This case underscores the importance of considering CM-TMA in the differential diagnosis of posttransplant TMA and in patients with end-stage kidney disease of uncertain origin, demonstrating that age alone should not preclude diagnostic consideration, and supports ravulizumab as an effective therapeutic option in this setting.<\/jats:p>","DOI":"10.3389\/fmed.2026.1702864","type":"journal-article","created":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T04:14:57Z","timestamp":1774930497000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Case Report: COVID-19 unmasks factor H mutation-driven hemolytic uremic syndrome in a previously undiagnosed septuagenarian kidney transplant recipient"],"prefix":"10.3389","volume":"13","author":[{"given":"Michael","family":"Fink","sequence":"first","affiliation":[{"name":"Division of Nephrology, Department of Internal Medicine, Medical University of Graz","place":["Graz, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marion","family":"Pollheimer","sequence":"additional","affiliation":[{"name":"Institute of Pathology, Medical University of Graz","place":["Graz, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander","family":"Kirsch","sequence":"additional","affiliation":[{"name":"Division of Nephrology, Department of Internal Medicine, Medical University of Graz","place":["Graz, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander R.","family":"Rosenkranz","sequence":"additional","affiliation":[{"name":"Division of Nephrology, Department of Internal Medicine, Medical University of Graz","place":["Graz, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kathrin","family":"Eller","sequence":"additional","affiliation":[{"name":"Division of Nephrology, Department of Internal Medicine, Medical University of Graz","place":["Graz, 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