Donor Lymphocyte Infusion (DLI) Volume

Donor Lymphocyte Infusion (DLI) Volume
×10⁶/kg
kg
×10⁶/mL
Estimates volume of whole blood to process by apheresis to yield an appropriate DLI dosage.

Why Use

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.

When to Use

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.

Formula

(A) Absolute CD3 + lymphocyte count, cells/mL = donor WBC x donor % total lymphocytes x donor % CD3+ lymphocytes x 1,000 (B) Total CD3+ cells needed = weight, kg x CD3 + infusion dose, cells/kg x number of doses desired (C) Total blood volume needed, L = (B / A) / collection efficiency Note: percents should be expressed as fractions, e.g. 30% total lymphocytes should be 0.30 in equation (A). Example: For a 85 kg patient with WBC 6.2, 30% lymphocytes, 54% CD3 + lymphocytes who will receive 2 doses of 50 × 10⁶ cells/kg each, collection efficiency 50%: (A) Absolute CD3 + lymphocyte count = 6.2 x 10 3 x 0.30 x 0.54 x 1,000 = 1.004 x 10 6 cells/mL (B) Total CD3 + cells needed = 85 x (50 × 10⁶) x 2 = 8.5 x 10 9 CD3 + cells (C) Total blood volume needed, L = 8.5 x 10 9 / 1.004 x 10 6 / 0.5 = 16.9 L

Pearls / Pitfalls

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 5x10 7 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.

Advice

Discuss with apheresis nursing/technical staff the volume of whole blood to be processed. Ensure that cell therapy processing laboratory is also aware of the number of doses the final collection is to be divided into for infusion.

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