Phenotypic complexity of T regulatory subsets in patients with B-chronic lymphocytic leukemia

Abstract

Increased numbers of T regulatory (Treg) cells are found in B-chronic lymphocytic leukemia, but the nature and function of these Tregs remains unclear. Detailed characterization of the Tregs in chronic lymphocytic leukemia has not been performed and the degree of heterogeneity of among these cells has not been studied to date. Using 15-color flow cytometry we show that Treg cells, defined using CD4, CD25, and forkhead box P3 (FOXP3), can be divided into multiple complex subsets based on markers used for naïve, memory, and effector delineation as well as markers of Treg activation. Furthermore FOXP3+ cells can be identified among CD4+CD25− as well as CD8+CD4− populations in increased proportions in patients with chronic lymphocytic leukemia compared with healthy donors. Significantly different frequencies of naïve and effector Tregs populations are found in healthy donor controls compared with donors with chronic lymphocytic leukemia. A population of CCR7+CD39+ Tregs was significantly associated with chronic lymphocytic leukemia. This population demonstrated slightly reduced suppressive activity compared with total Tregs or Tregs of healthy donors. These data suggest that FOXP3-expressing cells, particularly in patients with chronic lymphocytic leukemia are much more complex for Treg sub-populations and transitions than previously reported. These findings demonstrate the complexity of regulation of T-cell responses in chronic lymphocytic leukemia and illustrate the use of high-dimensional analysis of cellular phenotypes in facilitating understanding of the intricacies of cellular immune responses and their dysregulation in cancer.

The Skewed Balance Between Tregs and Th17 in Chronic Lymphocytic Leukemia

“…We have recently been shown that the frequencies of both CD8 + FoxP3 + and future science group www.futuremedicine.com CD8 + CD25 + FoxP3 + Tregs were increased in CLL patients and correlated with disease progression [4]. Other study has also been confirmed our experience [77]. Nunes et al have also shown emergence of CD8 + PD-1 + replicative senescent phenotype in early stage CLL and its correlation with disease progression [78].…”

“…The functional capacity of Tregs is another important issue in the immunobiology of Tregs in CLL patients which is investigated in our [4] and some other studies [23,77]. The first report regarding the Tregs function in CLL was reported by Giannopoulos et al which showed that the higher frequencies of Tregs were correlated with decreased T-cell responses against viral and tumor antigens [24].…”

“…Increased frequency of both CD4+ and CD8 + Tregs which correlated with disease progression Intact function of Tregs [77] Increased frequency of CD4 + Tregs that correlated with disease progression The higher frequencies of Tregs were correlated with decreased T-cell responses against viral and tumor antigens [24] Increased frequency of CD4 + Tregs that correlated with disease progression Decreased frequency of Tregs after therapy with thalidomide [70] Increased formation of Tregs via CD27-CD70 interaction Increased resistance to apoptosis via increased levels of Bcl-2 antiapoptotic protein [71] Increased frequency of CD4 + Tregs that correlated with disease progression Tregs predict the time to initial treatment in early-stage CLL Intact function of Tregs [72] Increased frequency of CD4 + Tregs that correlated with disease progression [73,76] Increased frequency of CD4+ Tregs that correlated with disease progression Leukemic B cells induce FoxP3+ Tregs [74] The emergence of CD8 + PD-1 + replicative senescent phenotype in early stage CLL which correlated with disease progression [78] Tregs express cytotoxic markers such as CD107a and granzyme A and kill autologous leukemic B cells [79] Tregs inhibit effector T cells in part through the release of soluble CD25…”

“…REviEW Yousefi, Movassaghpour, Shamsasenjan et al CFSE (carboxyfluorescein diacetate succinimidyl ester) proliferation assay[72,77]. It is suggested that Tregs in CLL patients deprive effector T cells from IL-2 through secretion of soluble CD25, so which prevent antitumor responses exerted by effector T cells[80].…”

Studying the Human Immunome: The Complexity of Comprehensive Leukocyte Immunophenotyping

“…Before the final panel was assembled, numerous clones of antibodies and fluorochrome combinations of antibodies were tested in order to optimize the identification of cell populations and to prevent unnecessarily high amounts of spectral compensation. The feasibility of developing a panel of multiple 15-color tubes has been demonstrated in our laboratory, and the panel’s utility in describing complex alterations of the immune system in the context of disease and vaccination has been demonstrated (Biancotto et al 2012a, b). …”