Granulocyte transfusion is the infusion of granulocytes, a type of white blood cell, into a patient’s bloodstream. This intervention bolsters a patient’s immune defenses when their body cannot produce enough of these infection-fighting cells. It serves as a supportive measure, providing temporary immune support. The goal is to help patients combat severe infections, particularly those not responding to standard antimicrobial treatments.
Understanding Granulocyte Transfusion
Granulocytes are white blood cells including neutrophils, eosinophils, and basophils; neutrophils are the most abundant and functionally significant in these transfusions. These cells contain small, enzyme-filled granules released to destroy invading pathogens like bacteria and fungi. Granulocytes play a primary role in the innate immune system, serving as a first line of defense by rapidly responding to foreign invaders and engulfing them through phagocytosis.
A granulocyte transfusion involves transferring these specialized white blood cells from a healthy donor to a recipient. This procedure is distinct from other blood transfusions, as it targets a specific component of the immune system. The transfused granulocytes circulate in the recipient’s blood and migrate to infection sites, providing a temporary boost to their immune response. It is a supportive therapy, helping the body fight existing threats while underlying conditions are addressed or the patient’s bone marrow recovers.
When Granulocyte Transfusions Are Needed
Granulocyte transfusions are considered for patients with severe neutropenia, a condition characterized by an abnormally low count of neutrophils, which significantly increases the risk of life-threatening infections. Neutropenia can arise from intensive chemotherapy for cancer, bone marrow failure, or severe infections that suppress bone marrow function. For instance, patients undergoing chemotherapy or hematopoietic stem cell transplantation often develop severe neutropenia as a temporary side effect.
The decision to administer granulocyte transfusions is made when patients with severe neutropenia develop serious bacterial or fungal infections that have not responded adequately to conventional antibiotic or antifungal medications for 24 to 48 hours. These transfusions act as an adjunct to antimicrobial therapy, providing additional immune cells to help clear persistent infections. While not routine, it may be used in cases of documented or suspected life-threatening infections, especially invasive fungal infections, where the patient’s bone marrow is expected to recover eventually.
The Transfusion Process
The process involves a donor and a recipient, with steps to collect sufficient specialized cells. For the donor, the procedure begins the day before donation with medications like granulocyte colony-stimulating factor (G-CSF), sometimes combined with oral corticosteroids such as dexamethasone. These medications stimulate the donor’s bone marrow to produce and release more granulocytes into their bloodstream, optimizing collection. G-CSF is usually given as a subcutaneous injection, often 12 to 24 hours before the apheresis procedure.
On the day of donation, granulocytes are collected through apheresis. The donor’s blood is continuously drawn from one arm, processed by a machine to separate white blood cells, and returned to the other arm. This procedure can take two to three hours. Donors may experience mild side effects from G-CSF and dexamethasone, such as bone pain, headache, muscle aches, or flu-like symptoms, which are temporary. Granulocyte products contain some red blood cells and plasma, requiring ABO/Rh compatibility and crossmatching between donor and recipient to prevent adverse reactions.
Once collected, the granulocyte product is immediately prepared for transfusion. These cells have a very short lifespan, losing function within six hours and expiring within 24 hours of collection. The transfusion to the recipient is administered intravenously, usually through a standard blood filter. Patients are monitored during the infusion for reactions, which can include fever or chills; severe pulmonary complications are less common with modern collection methods.
Potential Outcomes and Considerations
Granulocyte transfusions are a supportive therapy for severe infections, particularly when other treatments have not been effective. Their efficacy can be variable, and they are used when other treatments fail in patients with severe, prolonged neutropenia and infections unresponsive to antibiotics. Some studies suggest a positive effect in critically ill patients, with reported clinical improvement, especially for fungal infections. However, the overall impact on patient mortality remains uncertain, and some evidence indicates these transfusions may not improve overall survival.
Patients receiving granulocyte transfusions may experience side effects or complications. Common reactions include fever, chills, and allergic responses, ranging from mild to severe. More serious, though rare, complications include transfusion-related acute lung injury (TRALI) or graft-versus-host disease (GVHD), though GVHD risk is significantly reduced by irradiating the product. The transfused granulocytes have a short lifespan within the recipient’s body, typically lasting only a few hours to a day, meaning repeated transfusions may be necessary until the patient’s bone marrow recovers.