Calprotectin, a Biomarker of COVID-19 Severity (CALPRO)

Overview

The purpose of this study is to provide new insights into the pathophysiology of emergency hematopoiesis detected in severe COVID-19 patients. The investigators aim to explore the ability of calprotectin to induce an immunosuppressive myeloid program at the hematopoietic stem and progenitor cell (HSPC) level, and to identify the receptor(s) involved in this effect. Since patients with a hematological malignancy demonstrate a very high propensity to develop a severe COVID-19, the investigators will explore how HSPCs collected from patients with a myeloid malignancy respond to calprotectin.

Emergency myelopoiesis in response to SARS-CoV-2 infection produce immunosuppressive myeloid cells with accumulation of immature granulocytes and loss of non-classical monocytes. Excessive release of calprotectin, the dimer of S100A8/A9 alarmins, by immature granulocytes and activated monocytes reflects this situation. A role of calprotectin has been previously described in the initiation and progression of chronic hematological malignancies such as myelodysplastic syndromes. To provide a rationale for the targeting of alarmin-driven signaling pathways and limit the pathogenic inflammatory response to SARS-CoV-2 infection, the role of calprotectin in the production of immunosuppressive cells from the bone marrow hematopoietic stem and progenitors cells needs to be investigated in patients with severe COVID-19 in comparison with patients with chronic myeloid malignancies (such as chronic myelomonocytic leukemia and myelodysplastic syndromes) and with age-mached healthy controls. A comprehensive and integrated multiomics approach will be used to decipher the features of immunosuppressive cells and identify therapeutic targets in deregulated pathways.