A Single-Tube 21-Color Multiparameter Flow Cytometry Improve the Sensitivity of B-ALL MRD Analysis.

BACKGROUND: Detection of minimal residual disease (MRD) by multiparameter flow cytometry (MFC) is a well-established risk stratification factor and therapeutic modification strategy in B acute lymphoblastic leukemia (B-ALL). However, current 8 color (8c)-MFC for MRD detection had the sensitivity of 0.01% with false negative or positive. Hence, a more sensitive and applicable MFC-MRD method is urgently needed. The aim of this study is to establish a single-tube 21c-MFC method to detect B-ALL MRD, evaluate its performance, and to investigate its preliminary clinical application. METHODS: We selected 21 markers to establish a single-tube 21c-MFC method. The repeatability and sensitivity of this method was validated by adding Nalm-6 cells to normal bone marrow. Samples from control group (n = 6), B-ALL group (n = 7) and complete remission (CR) group (n = 26) were detected by 21c- and 8c-MFC separately. The expression characteristics of these markers was analyzed in control and B-ALL group, and the consistency of 21c- and 8c-MFC in detecting MRD was compared. RESULTS: Repeatability of this method was 1.91% of CV and sensitivity was up to 0.005%. In control group, the expression of CD81, CD97, and CD200 gradually decreased and CD44, HLA-DR, CD73, and CD72 gradually increased with the maturation of normal B cells. In B-ALL group, CD73stro, CD81low, CD44stro, CD123stro, and CD58stro showed high-frequency expression. The consistency rate of 21c- and 8c-MFC in detecting MRD was 96%. CONCLUSIONS: A single-tube 21c-MFC method was established for MRD detection in B-ALL and had higher sensitivity than the 8c-MFC method.

Standardization of Transfer across Labs between Flow Cytometers for Detection of Lymphocytes in Japanese Encephalitis Vaccinated Children.

An increasing number of laboratories need to collect data from multiple flow cytometers, especially for research projects performed across multiple centers. The challenges of using two flow cytometers in different labs include the lack of standardized materials, software compatibility issues, inconsistencies in instrument setup, and the use of different configurations for different flow cytometers. To establish a standardized flow cytometry experiment to achieve the consistency and comparability of experimental results across multiple centers, a rapid and feasible standardization method was established to transfer parameters across different flow cytometers. The methods developed in this study allowed the transfer of experimental settings and analysis templates between two flow cytometers in different laboratories for the detection of lymphocytes in Japanese encephalitis (JE)-vaccinated children. A consistent fluorescence intensity was obtained between the two cytometers using fluorescence standard beads to establish the cytometer settings. Comparable results were obtained in two laboratories with different types of instruments. Using this method, we can standardize analysis for evaluating the immune function of JE-vaccinated children in different laboratories with different instruments, diminish the differences in data and results among flow cytometers in multiple centers, and provide a feasible approach for the mutual accreditation of laboratory results. The standardization method of flow cytometer experiments will ensure the effective performance of research projects across multiple centers.

Detection of Polyfunctional T Cells in Children Vaccinated with Japanese Encephalitis Vaccine via the Flow Cytometry Technique.

T cell-mediated immunity plays an important role in controlling flavivirus infection, either after vaccination or after natural infection. The "quality" of a T cell needs to be assessed by function, and higher function is associated with more powerful immune protection. T cells that can simultaneously produce two or more cytokines or chemokines at the single-cell level are called polyfunctional T cells (TPFs), which mediate immune responses through a variety of molecular mechanisms to express degranulation markers (CD107a) and secrete interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-2, or macrophage inflammatory protein (MIP)-1α. There is increasing evidence that TPFs are closely related to the maintenance of long-term immune memory and protection and that their increased proportion is an important marker of protective immunity and is important in the effective control of viral infection and reactivation. This evaluation applies not only to specific immune responses but also to the assessment of cross-reactive immune responses. Here, taking the Japanese encephalitis virus (JEV) as an example, the detection method and flow cytometry color scheme of JEV-specific TPFs produced by peripheral blood mononuclear cells of children vaccinated against Japanese encephalitis were tested to provide a reference for similar studies.

Connexin 43 mediates PFOS-induced apoptosis in astrocytes.

Perfluorooctane sulfonate (PFOS) is a man-made environmental pollutant that is toxic to mammals. However, the neurotoxic effects of PFOS remain largely unexplored. In this study, we determined the role of an astrocyte specific gap junction protein, connexin 43 (Cx43), in PFOS-induced apoptosis. The rate of astrocyte apoptosis was higher in cortex astrocytes after PFOS treatment. These astrocytes also showed up-regulated expression of Cx43 and higher levels of cleaved caspase-3. Elevated ROS accumulation and decreased ΔΨm also confirmed the presence of PFOS-induced apoptosis. However, the exposure of astrocytes to PFOS together with carbenoxolone (CBX) significantly reduced both Cx43 and cleaved caspase-3 levels. These results indicate that Cx43 plays a proapoptotic role in PFOS-induced apoptosis in cortex astrocyte cells.