Adv Exp Med Biol - Cell Biology and Translational Medicine (2020) 10: 167–176 https://doi.org/10.1007/5584_2020_557 # Springer Nature Switzerland AG 2020 Published online: 10 July 2020 COVID-19 and Mesenchymal Stem Cell Treatment; Mystery or Not Tunc Akkoc Abstract On December 31, 2019, novel SARS-CoV2 spread from Wuhan China to more than 200 territories around world and the World Health Organization declared a COVID-19 pandemic on January 30, 2020. At this time there is no particular therapy, drug or vaccine available to deal with COVID-19. Today actual data indicates that about 17% of closed COVID-19 cases died. Health care professionals, ministry of health in countries and the public are trying to read the runes to see when the COVID-19 pandemic will be over. Although mild cases of COVID-19 can be controlled with antiviral, anti-inflammatory and immunomodulatory treatment, severe cases may need intensive care unit support and ventilation. Cytokine storms cause high inflammatory responses and pneumonia in severe cases. Mesenchymal stem cells are immunomodulatory and they have regenera- tive capacity. In this sense, mesenchymal stem cells may improve the patient’s clinical and immunological response to COVID-19. Keywords COVID-19 · Cytokine storm · Mesenchymal stem cells · Multiorgan failure · SARS CoV-2 Abbreviations ACE2 angiotensin-converting enzyme 2 ARDS acute respiratory distress syndrome CLR C-type lectin receptor CoV Corona viruses COVID-19 Coronavirus Disease 2019 CP convalescent plasma CRP C-reactive protein CRS cytokine release syndrome CT Chest computerized tomography GGOs ground glass opacities HCQ Hydroxychloroquine HIV human immunodeficient virus Ig Immunoglobulin IL Interleukin IP-10 or CXCL10 human interferon-inducible pro- tein 10 MCP-1 monocyte chemoattractant pro- tein-1 MERS-CoV middle East respiratory syn- drome-coronavirus MIP-lα macrophage inflammatory protein-1 alpha MOD multiorgan dysfunction N nucleocapsid protein NOD Nod-like receptor PAMPs pathogen associated molecular patterns Rt-PCR reverse transcriptase-polymerase chain reaction T. Akkoc (*) Department of Pediatric Allergy and Immunology, Marmara University Faculty of Medicine, İstanbul, Turkey e-mail: tuncakkoc@gmail.com 167