Human erythroid progenitors are directly infected by SARS-CoV-2: implications for emerging erythropoiesis in severe COVID19 patients.

Encabo, Hector Huerga; Grey, William; Garcia-Albornoz, Manuel; Wood, Henry; Ulferts, Rachel; Aramburu, Iker Valle; Kulasekararaj, Austin G.; Mufti, Ghulam; Papayannopoulos, Venizelos; Beale, Rupert; Bonnet, Dominique

We document here that intensive care COVID19 patients suffer a profound decline in hemoglobin levels but show an increase of circulating nucleated red cells, suggesting that SARS-CoV-2 infection either directly or indirectly induces stress erythropoiesis. We show that ACE2 expression peaks during erythropoiesis and renders erythroid progenitors vulnerable to infection by SARS-CoV-2. Early erythroid progenitors, defined as CD34-CD117+CD71+CD235a-, show the highest levels of ACE2 and constitute the primary target cell to be infected during erythropoiesis. SARS-CoV-2 causes the expansion of colony formation by erythroid progenitors and can be detected in these cells after two weeks of the initial infection. Our findings constitute the first report of SARS-CoV-2 infectivity in erythroid progenitor cells and can contribute to understanding both the clinical symptoms of severe COVID19 patients and how the virus can spread through the circulation to produce local inflammation in tissues, including the bone marrow.