What is the process for calculating donor lymphocyte collection using Apheresis (Automated Peripheral Blood Hematopoietic Progenitor Cell Collection)?

From the Guidelines

To calculate donor lymphocyte collection with apheresis, I recommend using the target CD3+ T cell dose and the donor's pre-collection CD3+ count to determine the blood volume that needs to be processed. For a standard donor lymphocyte infusion (DLI), process approximately 10-15 liters of blood through the apheresis machine to collect 1-5 × 10^7 CD3+ cells/kg recipient weight. The calculation formula is: Blood volume to process (L) = (Target CD3+ cell dose × recipient weight) ÷ (donor CD3+ count × collection efficiency). Collection efficiency typically ranges from 40-60% for most apheresis devices, as noted in various studies 1. Prior to collection, donors should avoid aspirin and NSAIDs for 48 hours to prevent bleeding complications. The procedure generally takes 2-4 hours, during which calcium supplementation may be needed to prevent citrate-related symptoms, as seen in other apheresis procedures 1. This calculation method ensures adequate cell collection while minimizing donor time on the apheresis machine. The collected lymphocytes are then typically cryopreserved in DMSO and can be administered in escalating doses based on the patient's risk of graft-versus-host disease and need for graft-versus-leukemia effect. It's also important to consider the patient's total blood volume, as those with small total blood volumes may require a red cell prime due to the extracorporeal volume of the apheresis machine, as mentioned in recent guidelines 1. Pre- and postprocedure complete blood counts and hemoglobin fractionation should be obtained to maximize procedure safety and efficacy. Automated apheresis devices are preferred over manual methods for their efficiency and ability to rapidly reduce HbS levels, but they require specialized equipment and trained personnel. Overall, the goal is to achieve the target CD3+ T cell dose while ensuring the safety and comfort of the donor, and recent studies support the use of apheresis for this purpose 1.

Some key points to consider when calculating donor lymphocyte collection with apheresis include:

• Target CD3+ T cell dose
• Donor's pre-collection CD3+ count
• Blood volume to process
• Collection efficiency
• Donor's total blood volume
• Need for red cell prime
• Pre- and postprocedure complete blood counts and hemoglobin fractionation
• Use of automated apheresis devices
• Trained personnel and specialized equipment
• Patient's risk of graft-versus-host disease and need for graft-versus-leukemia effect.

By following these guidelines and considering the individual patient's needs, healthcare providers can ensure safe and effective donor lymphocyte collection with apheresis.

From the FDA Drug Label

1. 4 Patients Undergoing Autologous Peripheral Blood Progenitor Cell Collection and Therapy ZARXIO is indicated for the mobilization of autologous hematopoietic progenitor cells into the peripheral blood for collection by leukapheresis [see Clinical Studies (14.4)].

The process for calculating donor lymphocyte collection using Apheresis is not directly stated in the provided drug label. The FDA drug label does not answer the question.

From the Research

Donor Lymphocyte Collection using Apheresis

The process for calculating donor lymphocyte collection using Apheresis involves several steps and considerations.

• The volume of blood to be processed is a critical factor in determining the yield of CD3+ lymphocytes 2.
• A linear correlation was found between the number of CD3+ cells collected and the processed blood volume, up to 12,000 ml 2.
• The use of granulocyte colony stimulating factor (G-CSF) can increase the yield of CD3+ lymphocytes, but the effect is not always significant 3, 4.
• The yield of CD3+ lymphocytes can be estimated based on the number of CD3+ cells in the peripheral blood, enabling the estimation of the volume of blood to process before apheresis 5.

Factors Affecting Lymphocyte Yield

Several factors can affect the yield of lymphocytes during apheresis, including:

• The dose of G-CSF used for priming 3
• The volume of blood processed 2
• The number of CD3+ cells in the peripheral blood 5
• The use of other cytokines, such as granulocyte macrophage colony stimulating factor (GM-CSF) and Flt-3 Ligand 4

Safety and Adverse Events

The safety of the apheresis procedure is a critical consideration, with potential adverse events including:

• Cytoreduction, resulting in decreased platelet and lymphocyte counts 2
• Mild vaso-vagal reactions and citrate-related lip paresthesia 2
• The need for specially trained machine operators and expensive equipment 6