Technique for single-step lymphocyte isolation from an endoscopic biopsy specimen for the diagnosis of gastrointestinal lymphoma. MethodsX. 2020;7:101095. [PMID: 33102158 PMCID: PMC7569335 DOI: 10.1016/j.mex.2020.101095]

Flow cytometry: Aspects and application in plant and biological science

Flow cytometry is a potent method that enables the quick and concurrent investigation of several characteristics of single cells in solution. Photodiodes or photomultiplier tubes are employed to detect the dispersed and fluorescent light signals that are produced by the laser beam as it passes through the cells. Photodetectors transform the light signals produced by the laser into electrical impulses. A computer then analyses these electrical impulses to identify and measure the various cell populations depending on their fluorescence or light scattering characteristics. Based on their fluorescence or light scattering properties, cell populations can be examined and/or isolated. This review covers the basic principle, components, working and specific biological applications of flow cytometry, including studies on plant, cell and molecular biology and methods employed for data processing and interpretation as well as the potential future relevance of this methodology in light of retrospective analysis and recent advancements in flow cytometry.

Increased CCR4+ and Decreased Central Memory CD4+ T Lymphocytes in the Background Gastric Mucosa of Patients Developing Gastric Cancer After Helicobacter pylori Eradication: An Exploratory Study

The composition of lymphocytes in the gastric mucosa following the eradication of Helicobacter pylori (H. pylori) in patients with and without gastric cancer has not been compared. This study performed a single spot analysis of gastric mucosal lymphocytes after H. pylori eradication in patients with (n = 13) and without (n = 20) gastric cancer. Our comprehensive analysis of lymphocyte composition in the gastric mucosa revealed that: i) the proportion of CD8⁺/CD3⁺ cells was relatively higher in the peri-tumor mucosa than in the background mucosa; ii) the proportion of CCR4⁺/CD3⁺ cells was higher, and the ratio of CD62L⁺/CD3⁺CD4⁺ cells was relatively lower in the gastric mucosa of cancer patients than in non-cancer patients; and iii) the proportion of CD45RA^-CD62L⁺/CD3⁺CD4⁺ cells, namely, the central memory CD4⁺ T-cell fraction, was lower in the gastric mucosa of cancer patients than in non-cancer patients. Although the exact mechanism of the altered proportions of CCR4⁺/CD3⁺ and central memory CD4⁺ cells in the gastric mucosa of patients with cancer is unknown, focusing on lymphocytes in the gastric mucosa might help improve our understanding of gastric cancer development after H. pylori eradication.

Site-specific differences in T lymphocyte composition of the gastric mucosa after Helicobacter pylori eradication

In our earlier work, we revealed that inflammation of the lesser curvature of the gastric body and antrum could constitute independent risk factors for gastric cancer development, while inflammation of the greater curvature was not. The aims of this study were as follows: first, to reveal the differences between T lymphocyte populations of the gastric antrum and the greater and lesser curvatures of the gastric body in patients after Helicobacter pylori eradication; second, to analyze the correlation between the composition of the stomach-resident T lymphocytes and time from H. pylori eradication; and third, to evaluate the sex differences in T lymphocyte subsets after H. pylori eradication. To investigate site-specific differences in stomach-resident T lymphocytes after H. pylori eradication, we performed flow cytometry analysis on samples taken from the gastric antrum, greater curvature of the gastric body, and lesser curvature of the gastric body of 20 patients. We also analyzed the correlation between the composition of the stomach-resident T lymphocytes and the time from H. pylori eradication. The lymphocyte subsets of the antrum and lesser curvature of the body were similar. In contrast, compared to those in the greater curvature of the gastric body, CD4+/CD3+ lymphocyte subsets (43.8 ± 19.4% vs 31.7 ± 14.6%) were elevated in the lesser curvature of the body, whereas CD8+/CD3+ (67.1 ± 21.3% vs 80.4 ± 12.0%), CD7+/CD3+ (91.2 ± 4.6% vs 93.7 ± 3.8%), CCR4+/CD3+ (7.7 ± 8.1% vs 10.4 ± 7.0%), CD45RA+/CD3+CD4+ (27.2 ± 24.8% vs 39.5 ± 20.8%), and CD45RA+/CD3+CD4- (14.2 ± 11.1% vs 18.7 ± 11.5) were lower. Linear regression analysis showed a negative correlation between the time after H. pylori eradication and CD4+/CD3+ (P < .05, R2 = 0.198). There were no significant differences between men and women with respect to the lymphocyte populations. These results indicate that there are site-specific differences in lymphocyte composition in the stomach after H. pylori eradication.

Characterization of Gastric Tissue-Resident T Cells in Autoimmune and Helicobacter pylori-Associated Gastritis

Data regarding the in-depth surface marker profiles of gastric tissue-resident lymphocytes in autoimmune and Helicobacter pylori-associated gastritis are lacking. In this study, we investigated potential differences in lymphocyte composition between these profiles. We enrolled patients with autoimmune (n = 14), active (current infection of H. pylori in the stomach; n = 10), and inactive gastritis (post-eradication of H. pylori; n = 20). Lymphocytes were isolated from the greater curvature of the stomach and lesser curvature of the body and analyzed using flow cytometry. The CD8+/CD3+ and CD4+/CD3+ ratios differed between the samples. Body CD4+/antrum CD4+, which is calculated by dividing the CD4+/CD3+ ratio in the body by that in the antrum, was significantly higher in autoimmune gastritis (3.54 ± 3.13) than in active (1.47 ± 0.41) and inactive gastritis (1.42 ± 0.77). Antrum CD8+/CD4+ in autoimmune gastritis (7.86 ± 7.23) was also higher than that in active (1.49 ± 0.58) and inactive gastritis (2.84 ± 2.17). The area under the receiver operating characteristic curve of antrum CD8+/CD4+ was 0.842, and the corresponding optimal cutoff point was 4.0, with a sensitivity of 71.4% and a specificity of 93.3%. We propose that an antrum CD8+/CD4+ ratio > 4.0 is a potential diagnostic marker for autoimmune gastritis.

Isolation of lymphocytes from the human gastric mucosa

Flow cytometry is widely used for lymphocyte immunophenotyping in clinical settings. However, few studies have applied it for analyzing lymphocytes of the gastric mucosa. This review offers an overview of methodologies for isolating lymphocytes from the human stomach. Previously reported articles were reviewed, focusing on procedures for isolating human gastric mucosal lymphocytes. Helicobacter pylori-associated peptic diseases and gastric cancer are two major subjects of research in this field. Enzymatic dissociation, mechanical dissociation, or a combination of the two have been used to isolate lymphocytes from the stomach. Intra-epithelial and lamina propria lymphocytes were separately isolated in several studies. We also summarize the history and present trends in analyzing lymphocytes in patients with gastric disease.