Background Chimeric Antigen Receptor T-cell (CAR T-cell) therapy is a promising treatment option for patients with refractory or relapsed B-cell malignancies. The success of this therapy depends on the efficient collection of lymphocytes (CD3+ T cells) through apheresis. This study analyzed the factors influencing CD3+ cell counts in apheresis products for CAR T-cell therapy. Methods This exploratory analysis evaluated patients enrolled in the registration phase I/II trials of talicabtagene autoleucel at a tertiary care oncology centre in Western India. Patients were enrolled after obtaining informed consent. The study was approved by the Institutional Ethics Committee and the Central Drugs Standard Control Organisation (CDSCO), and registered with the Clinical Trials Registry of India. A total of 48 autologous lymphocytapheresis procedures were performed on 44 patients with refractory or relapsed lymphoma (predominantly diffuse large B-cell lymphoma) or B-acute lymphoblastic leukemia. Pre-apheresis hematological parameters and flow cytometry were used to estimate absolute lymphocyte counts and peripheral blood CD3+ cell counts. Predictive factors for CD3+ cells in the product were analyzed using the Pearson correlation coefficient and regression models by the Statistical Package for Social Sciences software (Version 25.0, Armonk, NY: IBM Corp.), and p-values <0.05 were considered statistically significant. Results Pre-apheresis parameters like total leukocyte count, absolute lymphocyte count, and circulating CD3⁺ cell count were all positively correlated with the absolute CD3+ cell yield in the apheresis product (p < 0.05). Importantly, these associations remained significant in multivariate analysis, highlighting their independent predictive value for the harvested CD3+ count. Additionally, lower pre-apheresis hematocrit and higher platelet levels were independently associated with reduced CD3+ recovery. Notably, the targeted CD3+ cell dose was successfully achieved in 96 % (46/48) of collections. Conclusion Pre-apheresis total leukocyte count, absolute lymphocyte counts, CD3+ cells, hematocrit, and platelet counts are key factors influencing the successful collection of CD3+ cells during apheresis. Understanding these variables is crucial for optimizing lymphocyte collection for CAR T-cell manufacturing.
Introduction Hematological biomarkers from routine tests are attractive for their accessibility and clinical applicability, particularly indices derived from the complete blood count. Establishing reference intervals is essential for accurate interpretation, requiring healthy populations and standardized methods following Clinical and Laboratory Standards Institute guidelines. Objective To establish reference intervals for complete blood count-derived indices in healthy adults. Methods This cross-sectional study analyzed baseline data from 2230 participants aged 35–74 years in the Brazilian Longitudinal Study of Adult Health. Individuals with inflammatory conditions or hematological extremes (<1st and >99th percentiles) were excluded. Evaluated cellular parameters comprised five inflammatory ratios (neutrophil-to-lymphocyte, platelet-to-lymphocyte, lymphocyte-to-monocyte, monocyte-to-lymphocyte, and derived neutrophil-to-lymphocyte) and three composite indices (systemic inflammatory response, aggregate index of systemic inflammation, and systemic immune-inflammation). Reference intervals corresponded to the 2.5th–97.5th percentiles. Group differences by sex and age were evaluated using Mann–Whitney and Harris–Boyd tests. Results Males constituted 54.3% of the sample, and 92.0% of the participants were aged 35–59 years. Neither sex nor age required data stratification. The established reference intervals were: neutrophil-to-lymphocyte ratio (0.95–3.28), platelet-to-lymphocyte ratio (77.25–213.27), lymphocyte-to-monocyte ratio (2.27–7.17), monocyte-to-lymphocyte ratio (0.14–0.44), derived neutrophil-to-lymphocyte ratio (0.72–2.33), systemic inflammatory response index (0.33–1.89), aggregate index of systemic inflammation (69.85–460.01), and systemic immune-inflammation index (201.64–830.02). Conclusion These reference intervals provide a basis for clinical and epidemiological studies on subclinical inflammation and chronic disease risk.
