What is CAR-T Cell Apheresis?
CAR-T cell apheresis refers to the collection of a patient's own T lymphocytes via leukapheresis for the purpose of manufacturing Chimeric Antigen Receptor T-cell (CAR-T) therapy products. Unlike traditional therapeutic apheresis — which removes a pathogenic substance from blood — CAR-T leukapheresis is a manufacturing input collection: the cells collected are sent to a commercial manufacturing facility where they are genetically engineered to express a chimeric antigen receptor targeting a specific tumor antigen, expanded, and returned to the patient as a living drug.
This represents a paradigm shift in apheresis practice. The apheresis nurse and technologist are no longer just treating a disease — they are manufacturing the starting material for a potentially curative cancer therapy. The quality of the collected product directly determines the quality of the final CAR-T product and, ultimately, patient outcomes. This places extraordinary importance on collection technique, quality metrics, and patient optimization prior to collection.
As of August 2024, six CAR-T products are FDA-approved, with dozens more in clinical trials. The AABB has published a dedicated volume — Apheresis: Principles and Practice, 4th Edition, Volume 3: Cellular Therapy Apheresis (2025) — which formalizes standards and best practices for this rapidly growing subspecialty. Note: This text was not directly accessed in building this page; it is listed as a recommended resource for clinicians seeking the complete reference.
The CAR-T Manufacturing Process
Patient Evaluation
Oncology team determines CAR-T eligibility. Apheresis team reviews CBC, prior treatments, vascular access.
Leukapheresis Collection
Apheresis nurse collects mononuclear cells (T cells, monocytes) using continuous-flow centrifugation. 4–6 hours.
Product Shipment
Collected cells are cryopreserved and shipped to the manufacturer's facility (e.g., Novartis, Kite/Gilead, Bristol Myers Squibb).
Genetic Engineering
T cells are activated, transduced with a viral vector encoding the CAR construct, and expanded over 2–4 weeks.
Lymphodepletion
Patient receives conditioning chemotherapy (fludarabine + cyclophosphamide) to deplete endogenous lymphocytes and create space for CAR-T cells.
CAR-T Infusion
Engineered CAR-T cells are infused. Cells expand in vivo and target tumor cells expressing the target antigen.
FDA-Approved CAR-T Products (as of 2024)
All six approved products require autologous leukapheresis collection. Each product has specific collection requirements that the apheresis team must follow per the manufacturer's protocol.
| Manufacturer | Novartis |
| Approved | 2017 (first CAR-T) |
| Indication | B-ALL (pediatric/young adult), DLBCL, FL |
| Manufacturer | Kite/Gilead |
| Approved | 2017 |
| Indication | DLBCL, PMBCL, FL, MCL |
| Manufacturer | Kite/Gilead |
| Approved | 2020 |
| Indication | MCL, B-ALL (adult) |
| Manufacturer | Bristol Myers Squibb |
| Approved | 2021 |
| Indication | DLBCL, FL, MCL, CLL/SLL |
| Manufacturer | Bristol Myers Squibb |
| Approved | 2021 |
| Indication | Relapsed/refractory multiple myeloma |
| Manufacturer | Janssen/Legend Biotech |
| Approved | 2022 |
| Indication | Relapsed/refractory multiple myeloma |
Abbreviations: B-ALL = B-cell acute lymphoblastic leukemia; DLBCL = diffuse large B-cell lymphoma; FL = follicular lymphoma; MCL = mantle cell lymphoma; PMBCL = primary mediastinal B-cell lymphoma; CLL = chronic lymphocytic leukemia; SLL = small lymphocytic lymphoma; BCMA = B-cell maturation antigen.
The Leukapheresis Collection Procedure
| Parameter | Standard Approach |
|---|---|
| Instrument | Continuous-flow centrifugation (Spectra Optia® or COBE® Spectra); product-specific protocols required |
| Collection program | MNC (mononuclear cell) collection program; some products require specific instrument settings per manufacturer IFU |
| Target cells | CD3+ T lymphocytes (primary target); monocytes collected simultaneously |
| Typical collection volume | 10–15 liters processed (2–3 blood volumes) |
| Duration | 4–6 hours depending on patient CBC and target cell dose |
| Anticoagulation | ACD-A (acid citrate dextrose); citrate toxicity monitoring essential |
| Vascular access | Large-bore peripheral IV (preferred if adequate) or apheresis catheter; avoid femoral if possible |
| Product volume | Typically 40–200 mL of MNC product; product-specific target cell dose determines endpoint |
| Cryopreservation | Product cryopreserved in DMSO-containing media immediately after collection; shipped on dry ice to manufacturer |
| Chain of custody | Strict chain of custody documentation required; product labeled with patient-specific identifiers per manufacturer and FDA requirements |
Quality Metrics — What Makes a Good Collection
The quality of the leukapheresis product directly impacts the success of CAR-T manufacturing. Poor collections can result in manufacturing failures, delays in treatment, or suboptimal CAR-T products. The following metrics are monitored:
CD3+ T Cell Count
Minimum total CD3+ T cells required for manufacturing. Target varies by product — review manufacturer IFU.
Cell Viability
Minimum viable cell percentage post-collection. Low viability predicts manufacturing failure.
Monocyte Contamination
High monocyte content can inhibit T-cell expansion during manufacturing. Optimize collection to minimize.
Collection Efficiency
Percentage of circulating target cells collected. Low CE may require extended collection or re-collection.
Patient-Specific Challenges in CAR-T Collection
CAR-T patients are among the most complex encountered in the apheresis setting. Prior chemotherapy, disease burden, and cytopenias create unique collection challenges:
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Lymphopenia from Prior Chemotherapy
Heavily pretreated patients may have low absolute lymphocyte counts (ALC), reducing the number of available T cells. A pre-collection CBC with differential is essential. ALC <0.5×10⁹/L predicts difficult collections. Some centers use G-CSF or plerixafor to mobilize cells, though this is product-specific.
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T-Cell Exhaustion
Prior immunotherapy (checkpoint inhibitors, prior CAR-T) can cause T-cell exhaustion, producing cells with reduced proliferative capacity. Exhausted T cells may collect normally but fail to expand during manufacturing. Timing of collection relative to prior immunotherapy is critical.
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Thrombocytopenia
Platelet loss is expected during leukapheresis. Patients with baseline thrombocytopenia (<50×10⁹/L) are at increased bleeding risk. Pre-collection platelet transfusion may be required. Monitor platelet count before and after collection.
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Poor Vascular Access
Heavily treated patients often have compromised peripheral veins. Early evaluation for vascular access is essential. Central venous access (apheresis catheter) may be required. Avoid femoral access when possible due to infection risk in immunocompromised patients.
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High Tumor Burden / Circulating Tumor Cells
Patients with high circulating tumor cell burden (e.g., leukemic phase lymphoma) may have tumor cells contaminating the collection product. This can interfere with manufacturing. Discuss timing of collection with oncology team — some protocols prefer collection after cytoreduction.
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Citrate Toxicity
Long collection duration increases citrate exposure. Hypocalcemia symptoms (perioral tingling, muscle cramps, tetany) require calcium supplementation. Oral calcium carbonate or IV calcium gluconate per institutional protocol. Monitor ionized calcium if symptomatic.
Apheresis Nurse Checklist — Pre-Collection
- Confirm product-specific collection protocol and manufacturer IFU reviewed and available
- Verify patient identity using two identifiers; confirm product-specific chain-of-custody documentation initiated
- Review pre-collection CBC: ALC, platelet count, hematocrit, WBC differential
- Confirm no corticosteroids within 48–72 hours prior to collection (steroids reduce T-cell yield; product-specific restriction)
- Confirm no G-CSF within 24 hours unless specifically ordered for mobilization (product-specific)
- Assess vascular access; confirm adequate flow rates bilaterally (peripheral) or catheter function (central)
- Confirm calcium supplementation protocol in place; baseline ionized calcium if available
- Verify cryopreservation media and shipping materials prepared and available
- Confirm manufacturer collection kit lot number and expiration date documented
- Educate patient on procedure duration, expected sensations (citrate tingling), and importance of remaining still
Regulatory Framework
CAR-T leukapheresis collections are regulated as human cells, tissues, and cellular and tissue-based products (HCT/Ps) under 21 CFR Part 1271 and as biologics under the Public Health Service Act. The collection facility must comply with:
| Requirement | Standard |
|---|---|
| AABB accreditation | Cellular Therapy standards; AABB Apheresis: Principles and Practice, 4th Ed, Vol 3 (2025) is the current recommended reference textbook (purchase required; not directly accessed in building this site) |
| FDA registration | Facility must be registered as an HCT/P establishment with FDA |
| Manufacturer IFU compliance | Each CAR-T product has specific collection Instructions for Use (IFU) that must be followed exactly |
| Chain of custody | Unbroken documentation from patient identification through product shipment; critical for patient safety |
| Quality system | SOPs, training records, equipment qualification, and adverse event reporting per AABB and manufacturer requirements |
References
All references verified February 2026. DOIs and PubMed IDs confirmed against publisher records. Links open in a new tab.
- 1. U.S. Food and Drug Administration. Approved Cellular and Gene Therapy Products. FDA.gov. Updated 2025. FDA.gov Free — Official Source
- 2. Maus MV, Grupp SA, Porter DL, June CH. Antibody-modified T cells: CARs take the front seat for hematologic malignancies. Blood. 2014;123(17):2625–2635. doi:10.1182/blood-2013-11-435339 — PubMed 24578504 Free PMC Article
- 3. Connelly-Smith L, Alquist CR, Aqui NA, Hofmann JC, Klingel R, Onwuemene OA, et al. Guidelines on the Use of Therapeutic Apheresis in Clinical Practice — Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Ninth Special Issue. J Clin Apher. 2023;38(2):77–278. doi:10.1002/jca.22043 Free Full Text — PubMed 37017433
- 4. Lu W, Costa V, Wu DW, Alsammak M, Banez-Sese G, Chhibber V, et al. An Annual Review of Important Apheresis Articles in 2024 From the American Society for Apheresis Attending Physician Subcommittee. J Clin Apher. 2025;40(6):e70067. doi:10.1002/jca.70067 — PubMed 41157887
Disclaimer: This information is for educational purposes only. CAR-T leukapheresis must be performed according to product-specific manufacturer Instructions for Use (IFU) and institutional SOPs. Always consult the current manufacturer protocol and your institution's cellular therapy program for collection-specific requirements.