Growth Arrest-Specific Factor 6 (GAS6) Is Increased in COVID-19 Patients and Predicts Clinical Outcome

Albert Morales, Silvia Rojo Rello, Helena Cristobal, Aida Fiz-Lopez, Elisa Arribas, Montserrat Mari, Anna Tutusaus, Paloma de la Cal-Sabater, Gerry A. F. Nicolaes, Jose T. Ortiz-Perez, David Bernardo, Pablo Garcia de Frutos*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background: Growth arrest-specific factor 6 (GAS6) and the Tyro3, AXL, and MERTK (TAM) receptors counterbalance pro-inflammatory responses. AXL is a candidate receptor for SARS-CoV-2, particularly in the respiratory system, and the GAS6/AXL axis is targeted in current clinical trials against COVID-19. However, GAS6 and TAMs have not been evaluated in COVID-19 patients at emergency admission. Methods: Plasma GAS6, AXL, and MERTK were analyzed in 132 patients consecutively admitted to the emergency ward during the first peak of COVID-19. Results: GAS6 levels were higher in the SARS-CoV-2-positive patients, increasing progressively with the severity of the disease. Patients with initial GAS6 at the highest quartile had the worst outcome, with a 3-month survival of 65%, compared to a 90% survival for the rest. Soluble AXL exhibited higher plasma concentration in deceased patients, without significant differences in MERTK among SARS-CoV-2-positive groups. GAS6 mRNA was mainly expressed in alveolar cells and AXL in airway macrophages. Remarkably, THP-1 human macrophage differentiation neatly induces AXL, and its inhibition (bemcentinib) reduced cytokine production in human macrophages after LPS challenge. Conclusions: Plasma GAS6 and AXL levels reflect COVID-19 severity and could be early markers of disease prognosis, supporting a relevant role of the GAS6/AXL system in the immune response in COVID-19.

Original languageEnglish
Article number335
Number of pages11
Issue number4
Publication statusPublished - Apr 2021


  • AXL
  • COVID-19
  • GAS6
  • immune response
  • immunothrombosis
  • viral infection
  • vitamin K
  • Immune response
  • Covid-19
  • Viral infection
  • Axl
  • Immunothrombosis
  • Gas6
  • Mertk

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