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Background Aims: This white paper was developed to provide leukapheresis guidance for the collection of mononuclear cells from adult and pediatric patients who are destined for immune effector cell (IEC) therapies for commercial and research applications. Currently, there is considerable variability in leukapheresis processes and limited published information regarding best practices relevant to new cellular therapies, especially IECs. Herein the authors address critical leukapheresis questions in five domains to help guide consistent collection processes and ensure high-quality products. The first four domains are onboarding, pre-collection, collection and post-collection, with protocol feasibility, preparation, care and follow-up of the patient/donor at each step, respectively, and technical considerations during collection. The fifth domain of quality assurance focuses on ensuring product potency, purity, safety and auditing., Methods: The American Society for Apheresis (ASFA) Clinical Applications Committee (IEC Therapy Subcommittee) was charged by the society's board of directors with working collaboratively with other ASFA committees and organizations, including the Foundation for the Accreditation of Cellular Therapy, Association for the Advancement of Blood and Biotherapies, American Society for Transplantation and Cellular Therapy, National Marrow Donor Program and International Society for Cell & Gene Therapy, to develop guidelines regarding leukapheresis collection of cells destined for the manufacture of IEC therapies. After a review of the literature and discussion with members of the involved committees and various institutions, a draft guidance was created and circulated for comment and revision., Results: Critical aspects of apheresis that could affect the quality and quantity of the leukapheresis product were identified. These areas were then discussed and reviewed. After consensus, the best practice guidelines were proposed and accepted., Conclusions: In the current era of rapid growth of IEC therapies, it is important to address critical leukapheresis steps to provide high-quality products and more consistent practices and to eliminate redundant efforts., Competing Interests: Declaration of Competing Interest The authors have no commercial, proprietary or financial interest in the products or companies described in this article., (Copyright © 2022 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Background Aims: CD34 + cell count of hematopoietic progenitor cell products is often first determined using a product sample, with the final reported cell count obtained by multiplying cell count from the sample by the total product volume. Product volume may be determined by apheresis instruments used for collection or calculated based on specific gravity (SG). Here the authors sought to determine the discrepancies between these methods and the impact on patient care., Methods: A total of 262 products collected from 176 donors by apheresis were retrospectively reviewed. Volumes calculated by apheresis instruments were compared with volumes calculated based on SG. CD34 + cell/kg doses based on volumes from apheresis instruments and SG were also compared. Furthermore, among 42 patients who required multiple collections, the authors determined whether different calculation methods would have changed the number of procedures required., Results: The volumes for 253 products (96.6%) and CD34 + cell/kg doses for 257 products (98.1%) generated from apheresis instruments and SG were similar. Products with discrepant volumes when calculated using different methods were not associated with delayed engraftment. Forty patients who underwent multiple collections (95.2%) were under their collection goals during their first collection and would have required multiple procedures regardless of which method was used to calculate product volumes., Conclusions: Volumes determined based on SG did not provide a clear benefit over volumes determined by apheresis instruments. Hence, variation in volume calculation methods across different laboratories is likely to lead to minimal impact on patient care., (Copyright © 2021. Published by Elsevier Inc.)

Cytotoxic T cells (CTLs) are an important component of adaptive immunity. The study of antigen-specific CTLs in vivo is desirable yet difficult. Identification of the class I-restricted peptide used by CTLs for target recognition is often required for detailed studies, but is generally not known for most antigens. Toxoplasma gondii is a medically important, obligate intracellular parasite and is often used as a model for studies of parasite immunology. No class I-restricted peptides for CTLs are known. We show here a new and convenient method to detect T. gondii-specific CTLs in vivo. We engineered T. gondii tachyzoites to express the model antigen ovalbumin, for which many useful reagents and transgenic mice are available. Using ovalbumin-transgenic T. gondii tachyzoites, antigen-specific CTLs were detected in vivo, and at much earlier time points post-infection than previously reported. This new method has several additional advantages over current methods to detect T. gondii-specific CTLs., (Copyright 2010 Elsevier B.V. All rights reserved.)