White blood cells (leukocytes) are the immune system’s cellular defenders, constantly patrolling the bloodstream to fight off infectious invaders. These cells are indispensable for survival, especially during severe illness. Donating these specialized cells is a process known as leukapheresis, which allows a concentrated collection of white blood cells for transfusion into patients with compromised immune defenses. This donation is highly regulated because the collected cells have an extremely short shelf life, requiring a rapid match between donor and recipient.
The Specialized Need for White Blood Cell Donations
The need for donated white blood cells, particularly granulocytes, arises in patients who cannot produce enough of their own to combat life-threatening infections. This situation, called neutropenia, is common in individuals undergoing intensive chemotherapy or radiation for cancer treatment, as these therapies suppress bone marrow function. Patients who have recently received a bone marrow or stem cell transplant also require these transfusions until their new immune system can develop.
A transfusion of healthy donor white blood cells provides a temporary immune boost to fight bacterial or fungal infections unresponsive to standard antibiotics. This is often considered a measure of last resort to stabilize a patient’s condition and improve survival. Unlike red blood cells or platelets, donated granulocytes must be transfused into the patient within 24 hours of collection. This short window makes the donation process extremely urgent and patient-specific, necessitating a dedicated, on-demand system distinct from routine blood drives.
Donor Screening and Necessary Preparation
Becoming a white blood cell donor involves a rigorous screening process to ensure the safety of both the donor and the patient. Potential donors must meet general health criteria, including age and weight requirements, and undergo testing for blood-borne infectious diseases. Because the donation is often patient-specific, an initial blood draw is required to confirm compatibility, including human leukocyte antigen (HLA) matching and cytomegalovirus (CMV) status.
The preparation requires the use of granulocyte colony-stimulating factor (G-CSF), a naturally occurring protein administered as an injection. Donors typically receive daily subcutaneous injections of a synthetic version of G-CSF for four to five days leading up to the donation. This drug stimulates the bone marrow to rapidly produce and release a large number of white blood cells into the peripheral bloodstream. This mobilization is essential because only a small fraction of these cells normally circulate, making collection impossible without stimulation.
G-CSF can cause temporary side effects, most commonly mild bone pain, headaches, and fatigue, managed with non-aspirin pain medication. The bone pain is typically felt in areas of high bone marrow activity, such as the sternum and pelvis. The final injection is usually administered about 12 hours before the scheduled leukapheresis procedure to maximize the white blood cell count available for collection. Some centers may also administer a single dose of an oral corticosteroid, such as dexamethasone, to further enhance the number of cells collected.
Understanding the Leukapheresis Procedure
The white blood cell collection is performed through leukapheresis, an outpatient process that typically takes between two and four hours. The donor is comfortably seated, and the procedure involves drawing blood from one arm through a sterile intravenous line. The entire donation system uses single-use, disposable equipment, ensuring a safe and sterile process.
The drawn blood flows into an apheresis machine that uses centrifugation to separate the blood components based on their densities. As the blood spins, the white blood cells (lighter than red blood cells but heavier than plasma) settle into a distinct layer. Specialized sensors identify this layer, and the white blood cells, specifically granulocytes, are selectively diverted into a sterile collection bag.
To prevent clotting inside the machine and tubing, an anticoagulant, such as citrate, is continuously mixed with the drawn blood. The remaining blood components (red blood cells, platelets, and plasma) are warmed and returned to the donor’s body, usually through a second intravenous line in the opposite arm. Because the blood is processed outside the body, the donor must remain still throughout the multi-hour procedure to maintain the flow rate and prevent complications.
Recovery and Finding a Donation Center
Following leukapheresis, most donors feel recovered within a few days, though lingering fatigue or bone pain from the G-CSF may persist temporarily. The side effects of the stimulating injections typically resolve completely within 48 hours after the final dose. Donors are advised to avoid strenuous activity, heavy lifting, or contact sports for about a week to allow the needle insertion sites to heal.
The anticoagulant used during the procedure can temporarily deplete calcium levels, which may cause mild symptoms such as tingling around the mouth or lightheadedness. These effects are usually managed quickly by the donation center staff by administering calcium supplements. Individuals interested in becoming a white blood cell donor can find opportunities by contacting national blood donor organizations or specialized registries, such as those affiliated with major cancer centers or the National Marrow Donor Program. These organizations maintain databases of potential donors and coordinate the complex, time-sensitive process of matching and scheduling these life-saving donations.