What is emergency hematopoiesis (production of blood cells)?

From the Guidelines

Emergency hematopoiesis should be managed by addressing the underlying cause of the acute stress or injury, and supportive care measures such as blood transfusions and erythropoiesis-stimulating agents (ESAs) may be considered in certain cases, as recommended by the European Society for Medical Oncology (ESMO) clinical practice guidelines 1.

Key Considerations

• The process of emergency hematopoiesis involves the rapid production of blood cells, particularly white blood cells, in response to acute stress or injury, and is mediated by factors such as G-CSF, GM-CSF, and inflammatory cytokines.
• The decision to use ESAs, such as epoetin or darbepoetin, should be based on the patient's individual risk factors and clinical circumstances, including the severity of anemia and the presence of underlying hematological malignancies.
• According to the ESMO guidelines, ESAs may be considered for patients with chemotherapy-induced anemia and a hemoglobin (Hb) concentration that has declined to a level of 10 g/dL or below 1.
• The use of ESAs should be carefully weighed against the potential risks, including an increased risk of thromboembolism, and patients should be closely monitored for adverse effects.

Management Strategies

• Blood transfusions may be considered as a supportive care measure in cases of severe anemia or clinical circumstances that require rapid correction of anemia.
• Iron supplementation and other supportive care measures, such as folate and B12 deficiency correction, should be considered in patients with iron deficiency or other correctable causes of anemia.
• In patients with myelodysplastic syndromes, ESAs may be used to improve anemia, but the response to treatment should be carefully monitored and the dose adjusted accordingly 1.

Clinical Implications

• Emergency hematopoiesis is a critical physiological defense mechanism that allows the body to rapidly respond to threats by increasing immune cell production.
• Persistent emergency hematopoiesis can lead to bone marrow exhaustion or contribute to pathological conditions like myeloproliferative disorders if the stimulation becomes dysregulated.
• Clinicians should be aware of the potential risks and benefits of ESAs and other supportive care measures, and use clinical judgment to determine the best course of treatment for each individual patient.

From the FDA Drug Label

RELEUKO is indicated to increase survival in patients acutely exposed to myelosuppressive doses of radiation [see Clinical Studies (14.6)]. Increase survival in patients acutely exposed to myelosuppressive doses of radiation (Hematopoietic Syndrome of Acute Radiation Syndrome) (1. 6)

The granulocyte-colony stimulating factor (G-CSF), such as RELEUKO, is used to stimulate emergency hematopoiesis in patients acutely exposed to myelosuppressive doses of radiation. The recommended dosage for this indication is 10 mcg/kg/day subcutaneous injection 2, 2.

• Key points:
  • Indicated to increase survival in patients with Hematopoietic Syndrome of Acute Radiation Syndrome.
  • Recommended dosage: 10 mcg/kg/day.
  • Administration route: subcutaneous injection.
• Important consideration: The use of G-CSF in emergency hematopoiesis should be guided by the patient's clinical condition and the severity of the radiation exposure.

From the Research

Emergency Hematopoiesis

• Emergency hematopoiesis refers to the process of producing new blood cells in response to an emergency situation, such as severe blood loss or infection.
• This process involves the stimulation of stem cells in the bone marrow to produce various types of blood cells, including red blood cells, white blood cells, and platelets 3.
• The production of new blood cells is regulated by various cytokines and growth factors, such as erythropoietin, granulocyte colony-stimulating factor, and thrombopoietin 3.

Transfusion Therapy

• Transfusion therapy is often used in emergency situations to replace lost blood cells and restore oxygen delivery to tissues 4, 5, 6.
• The decision to transfuse blood products should be based on the patient's clinical condition, hemodynamic status, and laboratory results 4, 5.
• The use of whole blood transfusion is a debated strategy, but it is generally accepted that transfusions should be started early and crystalloid infusions limited 6, 7.

Blood Cell Production

• The production of red blood cells is stimulated by erythropoietin, which is produced in response to hypoxia or anemia 3, 5.
• The production of white blood cells is stimulated by granulocyte colony-stimulating factor, which is used to treat neutropenia in cancer chemotherapy or AIDS 3.
• The production of platelets is stimulated by thrombopoietin, which is used to treat thrombocytopenia in conditions such as idiopathic thrombocytopenic purpura 3.

Clinical Considerations

• The use of blood transfusions should be carefully considered, taking into account the potential benefits and risks, including transfusion reactions, infections, and increased mortality 4, 5.
• The age of transfused blood products may affect the risk of reaction and infection, with products stored for less than 21 days having the lowest risk 4.
• The use of recombinant human erythropoietin (rHuEPO) may offer an alternative to red blood cell transfusion in certain situations, such as in critically ill patients with anemia 5.