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Traditional manual gating strategies are often time-intensive, place a high burden on the analyzer, and are susceptible to bias between analyzers. Several automated gating methods have shown to exceed performance of manual gating for a limited number of cell subsets. However, many of the automated algorithms still require significant manual interventions or have yet to demonstrate their utility in large datasets. Therefore, we developed an approach that utilizes a previously published automated algorithm (OpenCyto framework) with a manually created hierarchically cell gating template implemented, along with a custom developed visualization software (FlowAnnotator) to rapidly and efficiently analyze immunophenotyping data in large population studies. This approach allows pre-defining populations that can be analyzed solely by automated analysis and incorporating manual refinement for smaller downstream populations. We validated this method with traditional manual gating strategies for 24 subsets of T cells, B cells, NK cells, monocytes and dendritic cells in 931 participants from the Health and Retirement Study (HRS). Our results show a high degree of correlation (r ≥ 0.80) for 18 (78%) of the 24 cell subsets. For the remaining subsets, the correlation was low (<0.80) primarily because of the low numbers of events recorded in these subsets. The mean difference in the absolute counts between the hybrid method and manual gating strategy of these cell subsets showed results that were very similar to the traditional manual gating method. We describe a practical method for standardization of immunophenotyping methods in large scale population studies that provides a rapid, accurate and reproducible alternative to labor intensive manual gating strategies. [ABSTRACT FROM AUTHOR]

Abstract: Based on the aptamer-conjugated core–shell near-infrared fluorescent nanoparticles (NIR-Nps) and fluorescence anisotropy measurement, the present study reported proof-of-principle for a rapid homogeneous assay approach that can detect target cancer cells without the need of the complicated separation steps in whole blood samples. Experimental investigation showed that the novel NIR-Nps have negligible background fluorescence and low inner filtration interference in complex biologic systems such as whole blood. The specific recognition characteristic of aptamer in whole blood samples was investigated by using the proposed fluorescence anisotropy method. The results showed that the fluorescent nanoparticle-tagged aptamer probes sequence could achieve specific recognition of the target cancer cells from complex mixtures including whole blood samples. And the reaction conditions for the binding between fluorescent nanoparticle-conjugated aptamer probes and target cancer cells were optimized. The present approach can exhibit sensitive and reproducible fluorescence anisotropy responses to the target cells concentration and the calibration curve showed good linearity when the target cells concentration is in the range from 4.0×103 to 7.0×105 cells/mL. Moreover, the present fluorescence anisotropy assay technique could be practically utilized for the detection of acute leukemia samples with improved capabilities and be comparable to the immunophenotyping methods clinically used. [Copyright &y& Elsevier]