{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,28]],"date-time":"2025-08-28T11:10:02Z","timestamp":1756379402056,"version":"3.44.0"},"reference-count":16,"publisher":"BMJ","issue":"3","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2025,3,15]]},"published-print":{"date-parts":[[2025,3]]},"abstract":"<jats:p>A previously healthy man in his 50s was admitted with severe COVID-19 pneumonia requiring extracorporeal membrane oxygenation (ECMO) support. He was found to have persistent eosinophilia, with a peak level of 7.5\u00d710<jats:sup>9<\/jats:sup>\/L. He had received multiple courses of steroids, including dexamethasone and methylprednisolone, with no improvement. On day 47, hydrocortisone was initiated for the treatment of septic shock. This resulted in the normalisation of the eosinophil count, which correlated with radiographic and clinical improvement. The patient was transitioned off ECMO and eventually weaned off mechanical ventilation. Studies conducted using the patient\u2019s serum identified circulating autoantibodies, which induced neutrophil extracellular traps (NETosis) and eosinophil extracellular traps (EETosis). A varying response of the eosinophils to different corticosteroids was observed in vivo that corresponded with the ex vivo experiments. This case highlights an unrecognised phenomenon of differential response to corticosteroids in severe COVID-19. Furthermore, this is the first reported case of EETosis in COVID-19.<\/jats:p>","DOI":"10.1136\/bcr-2024-260300","type":"journal-article","created":{"date-parts":[[2025,3,26]],"date-time":"2025-03-26T02:09:40Z","timestamp":1742954980000},"page":"e260300","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Autoimmune response to COVID-19 characterised by eosinophilia, NETosis and EETosis"],"prefix":"10.1136","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-1698-7885","authenticated-orcid":false,"given":"Aram","family":"Karkar","sequence":"first","affiliation":[{"name":"Department of Medicine, McMaster University, Hamilton, Ontario, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Parameswaran","family":"Nair","sequence":"additional","affiliation":[{"name":"McMaster University, Hamilton, Ontario, Canada"},{"name":"Firestone Institute for Respiratory Health, Hamiltn, Ontario, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manali","family":"Mukherjee","sequence":"additional","affiliation":[{"name":"McMaster University, Hamilton, Ontario, Canada"},{"name":"Firestone Institute for Respiratory Health, Hamiltn, Ontario, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6597-0839","authenticated-orcid":false,"given":"Natya G","family":"Raghavan","sequence":"additional","affiliation":[{"name":"McMaster University, Hamilton, Ontario, Canada"},{"name":"Firestone Institute for Respiratory Health, Hamiltn, Ontario, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2025,3,25]]},"reference":[{"key":"2025082803481186000_18.3.e260300.1","doi-asserted-by":"crossref","DOI":"10.1172\/JCI154886","article-title":"The intersection of COVID-19 and autoimmunity","volume":"131","author":"Knight","year":"2021","journal-title":"J Clin Invest"},{"key":"2025082803481186000_18.3.e260300.2","doi-asserted-by":"crossref","DOI":"10.1016\/j.jtauto.2022.100175","article-title":"Transient expression of antinuclear RNP-A antibodies in patients with acute COVID-19 infection","volume":"5","author":"Zhou","year":"2022","journal-title":"J Transl Autoimmun"},{"key":"2025082803481186000_18.3.e260300.3","doi-asserted-by":"crossref","DOI":"10.1016\/j.jtauto.2020.100073","article-title":"Prevalence of autoantibody responses in acute coronavirus disease 2019 (COVID-19)","volume":"3","author":"Lerma","year":"2020","journal-title":"J Transl Autoimmun"},{"key":"2025082803481186000_18.3.e260300.4","article-title":"Neutrophil extracellular traps in COVID-19","volume":"5","author":"Zuo","year":"2020","journal-title":"JCI Insight"},{"key":"2025082803481186000_18.3.e260300.5","doi-asserted-by":"publisher","DOI":"10.1182\/BLOOD.2020007008"},{"key":"2025082803481186000_18.3.e260300.6","doi-asserted-by":"crossref","DOI":"10.3389\/fimmu.2018.02763","article-title":"Eosinophil Extracellular Traps and Inflammatory Pathologies-Untangling the Web!","volume":"9","author":"Mukherjee","year":"2018","journal-title":"Front Immunol"},{"key":"2025082803481186000_18.3.e260300.7","article-title":"Circulating anti-nuclear autoantibodies in COVID-19 survivors predict long COVID symptoms","volume":"61","author":"Son","year":"2023","journal-title":"Eur Respir J"},{"key":"2025082803481186000_18.3.e260300.8","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1164\/rccm.201804-0809OC","article-title":"Sputum Antineutrophil Cytoplasmic Antibodies in Serum Antineutrophil Cytoplasmic Antibody\u2013Negative Eosinophilic Granulomatosis with Polyangiitis","volume":"199","author":"Mukherjee","year":"2019","journal-title":"Am J Respir Crit Care Med"},{"key":"2025082803481186000_18.3.e260300.9","doi-asserted-by":"crossref","DOI":"10.1186\/s13223-016-0174-5","article-title":"Airway autoimmune responses in severe eosinophilic asthma following low-dose Mepolizumab therapy","volume":"13","author":"Mukherjee","year":"2017","journal-title":"Allergy Asthma Clin Immunol"},{"key":"2025082803481186000_18.3.e260300.10","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1016\/j.jim.2017.06.005","article-title":"Improved recovery of functionally active eosinophils and neutrophils using novel immunomagnetic technology","volume":"449","author":"Son","year":"2017","journal-title":"J Immunol Methods"},{"key":"2025082803481186000_18.3.e260300.11","doi-asserted-by":"crossref","DOI":"10.3390\/microorganisms9020334","article-title":"Do Blood Eosinophils Predict in-Hospital Mortality or Severity of Disease in SARS-CoV-2 Infection? 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