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Purpose: Biallelic pathogenic NBAS variants manifest as a multisystem disorder with heterogeneous clinical phenotypes such as recurrent acute liver failure, growth retardation, and susceptibility to infections. This study explores how NBAS-associated disease affects cells of the innate and adaptive immune system. Methods: Clinical and laboratory parameters were combined with functional multi-parametric immunophenotyping methods in fifteen NBAS-deficient patients to discover possible alterations in their immune system. Results: Our study revealed reduced absolute numbers of mature CD56dim natural killer (NK) cells. Notably, the residual NK cell population in NBAS-deficient patients exerted a lower potential for activation and degranulation in response to K562 target cells, suggesting an NK cell–intrinsic role for NBAS in the release of cytotoxic granules. NBAS-deficient NK cell activation and degranulation was normalized upon pre-activation by IL-2 in vitro, suggesting that functional impairment was reversible. In addition, we observed a reduced number of naïve B cells in the peripheral blood associated with hypogammaglobulinemia. Conclusion: In summary, we demonstrate that pathogenic biallelic variants in NBAS are associated with dysfunctional NK cells as well as impaired adaptive humoral immunity. [ABSTRACT FROM AUTHOR]

Adoptive cellular therapy with immune effector cells (IECs) has shown promising efficacy against some neoplastic diseases as well as potential in immune regulation. Both inherent variability in starting material and variations in cell composition produced by the manufacturing process must be thoroughly evaluated with a validated method established to quantify viable lymphocyte subtypes. Currently, commercialized immunophenotyping methods determine cell viability with significant errors in thawed products since they do not include any viability staining. We hereby report on the validation of a flow cytometry-based method for quantifying viable lymphocyte immunophenotypes in fresh and cryopreserved hematopoietic cellular products. Using fresh or frozen cellular products and stabilized blood, we report on the validation parameters accuracy, uncertainty, precision, sensitivity, robustness and contamination between samples for quantification of viable CD3+, CD4+ T cells, CD8+ T cells, CD3–CD56+CD16+/– NK cells, CD19+ B cells and CD14+ monocytes of relevance to fresh and cryopreserved hematopoietic cellular products using the Cytomics FC500 cytometer (Beckman Coulter). The acceptance criteria set in the validation plan were all met. The method is able to accommodate the variability in absolute numbers of cells in starting materials collected or cryopreserved from patients or healthy donors (uncertainty of ≤20% at three different concentrations), stability over time (compliance over 3 years during regular inter-laboratory comparisons) and confidence in meaningful changes during cell processing and manufacturing (intra-assay and intermediate precision of 10% coefficient of variation). Furthermore, the method can accurately report on the efficacy of cell depletion since the lower limit of quantification was established (CD3+, CD4+ and CD8+ cells at 9, 8 and 8 cells/µL, respectively). The method complies with Foundation for the Accreditation of Cellular Therapy (FACT) standards for IEC, FACT-Joint Accreditation Committee of ISCT-EBMT (JACIE) hematopoietic cell therapy standards, International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use Q2(R1) and International Organization for Standardization 15189 standards. Furthermore, it complies with Ligand Binding Assay Bioanalytical Focus Group/American Association of Pharmaceutical Scientists, International Council for Standardization of Hematology/International Clinical Cytometry Society and European Bioanalysis Forum recommendations for validating such methods. The implications of this effort include standardization of viable cell immunophenotyping of starting material for cell manufacturing, cell selection and in-process quality controls or dosing of IECs. This method also complies with all relevant standards, particularly FACT-JACIE standards, in terms of enumerating and reporting on the viability of the "clinically relevant cell populations." [ABSTRACT FROM AUTHOR]

Adoptive cellular therapy with immune effector cells (IEC) has shown remarkable toxicity against tumor cells and potential in immune regulation. Both variability in cell content of starting material and compromised cell viability during manufacturing necessitate a validated method for quantifying viable lymphocyte subtypes individually. Currently-commercialized immunophenotyping methods report cell viability in thawed products with significant error since they do not include any viability staining. We hereby report on the validation of a flow cytometry-based method for quantifying viable lymphocyte- immunophenotypes in fresh and cryopreserved hematopoietic cellular products. Using fresh or frozen cellular products and stabilized blood, we report on the validation parameters: accuracy, uncertainty, precision, sensitivity, robustness and carry-over for quantification of viable CD3+, CD4+ T cells, CD8+ T cells, CD3-CD56+CD16+/- NK cells, CD19+ B cells and CD14+ monocytes of relevance to hematopoietic products and immune effector cell (IEC) products on the Cytomics FC500 Beckman Coulter cytometer. The acceptance criteria set in the validation plan were all met. The method is able to accommodate the variability in absolute numbers of cells in starting materials collected or cryopreserved from patients or healthy donors (uncertainty of 10% at 3 different concentrations), stability over time (compliance over 3 years during regular inter-laboratory comparisons), and confidence in meaningful changes during cell processing and manufacturing (intra-assay and intermediate precision of 10% CV). Furthermore, the method can accurately report on the efficacy of cell depletion, since the lower limit of quantification was established (CD3+, CD4+ and CD8+ cells at 9, 8 and 8 cells/µl, respectively). The method complies with FACT Standards for IEC, FACT-JACIE Hematopoietic Cell Therapy Standards, ICH Q2(R1) and ISO15189 standards. Furthermore, it complies with LBAFG-AAPS, ICSH/ICCS and European Bioanalysis Forum recommendations for validating such methods. The implications of this effort include: standardization of viable cell immunophenotyping of starting material for cell manufacturing, cell selection, in-process or dosing of immune effector cells. This method also complies with all relevant standards, particularly FACT-JACIE Standards in terms of enumerating and reporting on the viability of the "clinically relevant cell populations". [ABSTRACT FROM AUTHOR]