[Normal and emergency hematopoiesis: current concepts and clinical implications]

Area of Science:

• Hematology and Immunology
• Cell Biology
• Molecular Biology

Context:

• Recent technological progress enhances understanding of bone marrow histoarchitecture.
• Hematopoietic progenitor cells (HPCs) are crucial for hematopoiesis, maintaining self-renewal and differentiation.
• The interaction between HPCs and the marrow microenvironment is increasingly understood through multi-omics approaches.

Purpose:

• To elucidate the mechanisms of emergency hematopoiesis.
• To describe the characteristics and consequences of altered hematopoiesis during inflammation.
• To investigate the role of HPCs in innate immune responses.

Summary:

• Emergency hematopoiesis, induced by inflammatory signals, alters HPCs' genetic, epigenetic, proteomic, and metabolic profiles.
• This process increases myelopoiesis while decreasing lymphopoiesis and erythropoiesis.
• Key outcomes include increased HPC release into peripheral blood, extramedullary hemopoiesis, and the generation of innate immune memory and myeloid suppressor cells.

Impact:

• Altered neutrophil/lymphocyte and monocyte/lymphocyte ratios in blood counts indicate adverse prognostic value.
• Findings are relevant to chronic inflammatory diseases and neoplastic conditions.
• Provides insights into the plasticity of HPCs and their role in immune system adaptation.