Donor Lymphocyte Infusion (DLI) Volume

• Patients who have received allogeneic stem cell transplants may be given donor lymphocyte infusions (DLI) as a means to augment/enhance the graft-versus-tumor effect. These cell therapy products are typically collected from the original donor of the hematopoietic progenitor cell used for the initial allograft.
• This equation estimates the volume of allogeneic donor whole blood volume to process in order to achieve an appropriate DLI dose.

• DLI calculations rely on having a number of baseline clinical and laboratory values readily available from the donor, including the total white blood cell count and total lymphocyte percentage of the donor (typically obtained by automated CBC analysis), the percentage of total donor lymphocytes that are CD3+ T-cells (typically obtained by flow cytometry), as well as information needed about the recipient including their weight, the desired number of CD3+ cells/kg to be infused, and the number of doses to be infused; the latter two items are typically established by the recipient’s treating physician or transplant physician.
• If flow cytometry data are not readily available, it is reasonable to estimate that the percentage of total donor lymphocytes that are CD3+ is 50%.
• A typical goal for DLI procedures is to collect 1 dose of 5x10⁷ CD3+ T-cells/kg recipient body weight; however, this will vary from case-to-case.
• The calculation assumes a cellular collection efficiency of 50% by the apheresis instrument; this can vary somewhat from procedure-to-procedure.

DLI is an important aspect of allogeneic stem cell transplant management. However, this is an infrequently performed procedure with a complex equation used to estimate appropriate donor collection volumes. This calculation should promote accurate and evidence-based collection of DLI cell therapy products.