LEUKOPAKS

Mobilized & Non-Mobilized

What are Leukopaks?

Leukopak is a term the cell therapy community uses to refer to peripheral blood mononuclear cells (PBMCs)that are collected by apheresis. Although this is the common name, The Cellular Therapy Coding and Labeling Advisory Group (CTCLAG) formed in 2004 and includes major cellular therapy professional organizations such as: AABB, APBMT, ASTCT, ASFA, EBMT, FACT, ISBT, ISCT, JACIE, and WMDA have determined the ISBT 128 name for this product is MNC, Apheresis.

The leukapheresis procedure used to collect the leukopak is a dual arm apheresis collection procedure that is highly affected by the pre-donation white blood cell count of the donor and the donor’s total blood volume. These factors, along with the total nucleated cells desired in the leukopak, must be used to determine how long the donor should remain on the device.

While the number of cells in the leukopack are determined by donor characteristics and procedure time, the ratio of cells remains relatively constant. Most leukopaks contain up to 50% T cells, 20% monocytes, 10% B cells, and 10% NK cells, 3% granulocytes, with a 3% hematocrit.

Learn more about Bio Sharing Network’s leukopaks by contacting us directly here.

What are Mobilized Leukopaks?

Like the leukopak, mobilized leukopak is a term the cell therapy community adopted to reference hematopoietic progenitor cells (HPCs) collected by apheresis. These procedures use the principles of leukapheresis to collect CD34+ peripheral blood stem cells. The number of circulating HPCs is increased by subcutaneous injections of GCSF over a three-to-five-day period. The GCSF causes the donor’s bone marrow to release more HPCs into the circulation. Each donor responds differently to this “mobilization” process and, therefore, the pre-donation CD34+ cell count will be different. The CTCLAG has determine that the name for this product is HPC, Apheresis. More information here about non-mobilized leukopaks.

Recallable Donors

While many variables in leukopak content and viability can be controlled by experienced apheresis staff, there are often unknown reasons why one donor’s cells just work better in a specific process than do others. At BioSharing Network, we realize this phenomena occurs and can recall these “super donors” to return for repeated collections.

Leukopak Product Overview

  • Leukopak Collection Methods

    The Spectra Optia® Continuous Mononuclear Cell Collection protocol is used for all apheresis leukopak collections. Our centers have been collecting PBMC products for over 25 years and are subject matter experts with apheresis leukopak collection procedures and processes.

  • Collected to Pre-Defined Cell Target

    Leukopak products are collected to a pre-defined number of total nucleated cells with approximately half being CD3+. When collecting to a target, the desired TNC yield is reached or exceeded with 98% accuracy.

    However, if cells are collected using a pre-defined number of liters processed, the number of liters required to achieve the same number of cells may vary by 300%.

  • Eligibility Determination

    Leukopak donors are screened according to 21CFR 1271.75 using the questions found on the AABB uniform donor history questionnaire for cell therapy donors.

    Additional questions can be added to a supplemental screening tool upon request.

 

  • Leukopak donors are mobilized with 10 mcg/kg/day for five days with filgrastim.

    Mobilized donors receive a physical exam from a healthcare professional prior to filgrastim administration.

  • A standard IRB approved consent is used to inform the donor of the risk and reward of the donation. The donor is fully aware that they can discontinue participation at anytime during the process.

  • The anticoagulant used for leukopak collection is acid citrate dextrose-A (ACD-A). The ratio of ACD-A used is 11 parts whole blood to 1 part ACD-A or 12:1.

  • Plasma volume will vary based on the liters of blood processed and the donor’s pre-TNC count, but the mean product volume in 220mL. Upon request, additional plasma can be concurrently collected.

  • Sterility testing is performed on all units. The test method uses the Biomerieux BACT/ALERT system that complies with <USP> 71. Cultures are incubated for 14 days.

  • Testing is performed for all relevant communicable disease agents defined by the current edition of 21 CFR 610.40 and 21 CFR 1271.75.

    All testing is done in compliance with 21 CFR 1271.80 and 21 CFR 1271.85. Only reagents that have been FDA cleared for donor screening are used. Results of testing on the screening date and the date of collection can be provided on the COA if requested.

  • Along with lymphocyte, macrophage, NK or gamma delta T cell markers, 7AAD can be added to the flow cytometry assay to access the viability of specific cell populations.

  • A certificate of Analysis (COA) is provided with each product. The standard COA will include donor demographics and relative cell counts. The content of the COA can be customized to meet specific client needs including IDT and screening assays performed on the date of screening and the date of collection.

  • All donor identifying information is confidential. While donor and product assessment data can be provided to a client, the identity of the donor is never provided. Non-Disclosure Agreements are initiated with all clients and their product and process information is not shared with any other entity or individual.

  • Quality systems have been established and include a quality plan, identification of critical control points (CCP), and key elements that provide process control for each CCP. Supplies, reagents, and equipment are verified against vendor claims and processes are validated using written IQ, OQ and PQ validation plans. SOPs are in place for each process step and all relevant data is documented concurrent with the performance of the task. Training programs for staff include documented assessments of understanding. Each element of 21CFR 211 and 21CFR 1271 are included in the quality system.

  • What are cryopreserved leukopaks? Standard controlled rated freezing protocol uses volume reduced PBMCs where cryoprotectant is added to a final DMSO concentration of 10% in 70mL.

    Alternatively, a client’s custom method can be validated and used.

  • A standard dose of 25GY is used for irradiation of MNCs for feeder cell use. Custom doses that are multiples of 25 can be performed.

  • At the client’s request, leukopaks that will be used for feeder cells can be ficoll treated.