CAR-T Cell Apheresis

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

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.

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

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:

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:

• 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.

• 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.

• 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.

• 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.

• 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.

• 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