Flow cytometric immunophenotyping of peripheral blood lymphocyte subsets is a powerful tool for evaluating cellular immunity and monitoring immune-mediated diseases. The numbers and proportions of blood lymphocyte subsets are influenced by factors such as gender, age, ethnicity, and lifestyle. This study aimed to establish reference ranges for peripheral blood lymphocyte subsets in a healthy Korean population. Blood samples from 294 healthy adults were collected. Lymphocyte subsets were analyzed using a single-platform method with a flow cytometer; white blood cells and lymphocytes were analyzed using an automated hematology analyzer. The mean value of the white blood cell count was 5,665 cells/µl, and the mean values of the subtype counts (percentages) were as follows: lymphocytes, 1,928 cells/µl (35.08%); CD3+ cells, 1,305 cells/µl (67.53%); CD3+CD4+ cells, 787 cells/µl (40.55%); CD3+CD8+ cells, 479 cells/µl (25.23%); CD3-CD19+ cells, 203 cells/µl (10.43%); and CD3-CD56+ cells, 300 cells/µl (15.63%). Additionally, the CD4+/CD8+ ratio was 1.81. In this study, gender and age significantly influenced blood lymphocyte subsets. Our results demonstrate that, as with other populations, a healthy Korean population has its own, region-specific, lymphocyte subset reference ranges.

PurposeLittle is known about the clinical value of peripheral blood immune profiling. Here, we aimed to identify colorectal cancer (CRC)-related peripheral blood immune cells and develop liquid biopsy-based immune profiling models for CRC diagnosis.MethodsPeripheral blood from 131 preoperative patients with CRC and 174 healthy controls was analyzed by flow cytometry and automated hematology. CRC-related immune factors were identified by comparing the mean values of immune cell percentages and counts. Subsequently, CRC diagnostic algorithms were constructed using binary logistic regression.ResultsSignificant differences were observed in percentages and counts of white blood cells, lymphocytes, neutrophils, regulatory T cells, and myeloid-derived suppressor cells (MDSCs) of patients and controls. The neutrophil/lymphocyte and Th1/Th2 ratios were also significantly different. Likewise, the percentages and counts of peripheral blood programed death 1, cytotoxic T lymphocyte antigen 4, B-and T-lymphocyte attenuator, and lymphocyte activation gene-3 were higher in patients with CRC. The binary logistic regression model included 12 variables, age, CD3+%, NK%, CD4+CD279+%, CD4+CD25+%, CD4+CD152+%, CD3+CD366+%, CD3+CD272+%, CD3+CD223+%, CD158b−CD314+CD3−CD56+%, Th2%, and MDSCs cells/µL, for the prediction of cancer. Results of retrospective and prospective evaluation of the area under the curve, sensitivity, and specificity were 0.980 and 0.940, 91.53% and 85.80%, and 93.50% and 86.20%, respectively.ConclusionPeripheral blood immune profiling may be valuable in evaluating the immunity of CRC patients. Our liquid biopsy-based immune diagnostic method and its algorithms may serve as a novel tool for CRC diagnosis. Future largescale studies are needed for better characterization of its diagnostic value and potential for clinical application.

PurposeThis study aimed to assess the cytolytic activity and the phenotype of circulating blood immune cells in cancer patients by using a simple preparation of peripheral blood mononuclear cells (PBMCs).MethodsPeripheral blood was obtained from 94 diagnosed colorectal cancer (CRC) patients and 112 healthy donors. PBMCs were cocultured with K562 cells for 2 hours and lactate dehydrogenase released from the dead K562 cells was measured by using a spectrophotometer. Meanwhile, PBMCs were stained with fluorescence conjugated monoclonal antibodies (mAbs) and analyzed by flow cytometry.ResultsThe cytolytic activity of PBMCs were significantly different between CRC patient and healthy groups (8.82% ± 3.84% vs. 17.51% ± 8.57%; P < 0.001). However, no significant difference in the cytolytic activity was observed after surgery in the CRC patient group (before surgery, 8.82% ± 3.84% vs. after surgery, 9.95% ± 4.94%; P = 0.326). In addition, the percentage of peripheral blood natural killer cells was significantly higher in the preoperative patient group than in the healthy group (19.97% ± 11.51% vs. 15.60% ± 5.77%, P = 0.041). In contrast, the percentage of peripheral blood lymphocytes was lower in the preoperative patient group than in the healthy group (28.41% ± 8.31% vs. 36.4% ± 8.6%, P < 0.001).ConclusionThese results demonstrate that circulating blood immune cells of CRC patients are functionally impaired and undergo an immunophenotypic perturbation, and show that a simple preparation of PBMCs can be useful to evaluate cellular immunity in cancer.

Abstract. Cytotoxicity assays with patient peripheral blood mononuclear cell (PBMC)-derived natural killer (NK) cells are useful in evaluating the innate immunity of patients with cancer. However, the size of the NK cell population in PBMC preparations may have significant effects on the assay outcome. Therefore, the present study examined the effect of NK cell frequency in a cytotoxicity system to investigate NK cell immunity in post-surgical colorectal cancer patients. For this, hemacytotoxicity was assessed using PBMC preparations, and lymphocyte subset populations were analyzed in samples obtained from 47 patients and 45 healthy volunteers. In addition, a new theoretical parameter, the 'NK lytic index', was termed to represent the per-cell cytotoxicity and compensate for the NK cell frequency effect during PBMC preparations. Notably, the patterns of hemacytotoxicity and NK lytic index did not coincide in follow-up studies with consecutive patients following surgical intervention. In addition, it was determined that NK cell NKG2D expression influences NK lytic index, but not hemacytotoxicity. Transforming growth factor (TGF)-β-bound lymphocytes influenced hemacytotoxicity and NK lytic index. These findings indicate that total cell activity (hemacytotoxicity) is not a sum of per-cell activities (NK lytic indexes), suggesting that clinicians should employ NK lytic index in addition to hemacytotoxicity in order to precisely determine how to enhance NK cell immunity in patients with cancer, either focusing on recovering the number of NK cells or boosting NK cell activity in single cell levels, or both. IntroductionNatural killer (NK) cells, which serve critical roles in cancer immunity, are regarded as the first line of defense to eliminate transformed or malignant tumor cells (1). Therefore, multiple clinical laboratories have examined the implications of NK cell-mediated immunity in cancer and demonstrated that NK cells are functionally impaired in the majority of forms of cancer (2-4). Therefore, clinical attempts to boost endogenous NK cell activity, using biological response modifiers or the adoptive transfer of in vitro activated NK cells, have been investigated for the treatment of patients with cancer (5,6). However, a reliable tool to evaluate NK cell activity on a per-cell basis in each patient should be described prior to clinical application in order to design optimal treatment regimens, particularly since the degree of impaired NK cell activity and its etiology differ from patient to patient (7-9).In vitro cytotoxicity assays have been widely used in clinical laboratories to study NK cell function in patients with cancer. A feature of this assay system is the co-culture of effector cells with their specific target cells over a range of ratios, in which the cytotoxicity of NK cells against their target cells is measured by arithmetic calculation of the number of target cells killed during the given reaction. Purified peripheral NK cells from blood are a favored source of effector cells, but unfraction...