Induction of interleukin-2 receptor alpha chain expression of immature acute myelocytic leukemia cells

Bcl-2 Is Necessary to Counteract Bim and Promote Survival of TCRαβ+CD8αα+ Intraepithelial Lymphocyte Precursors in the Thymus

The precursors of TCRαβ+CD8αα+ intraepithelial lymphocytes (IEL) arise in the thymus through a complex process of agonist selection. We and others have shown that the proapoptotic protein, Bim, is critical to limit the number of thymic IEL precursors (IELp), as loss of Bim at the CD4+CD8+ double-positive stage of development drastically increases IELp. The factors determining this cell death versus survival decision remain largely unknown. In this study, we used CD4CreBcl2f/f mice to define the role of the antiapoptotic protein Bcl-2 and CD4CreBcl2f/fBimf/f mice to determine the role of Bcl-2 in opposing Bim to promote survival of IELp. First, in wild-type mice, we defined distinct subpopulations within PD-1+CD122+ IELp, based on their expression of Runx3 and α4β7. Coexpression of α4β7 and Runx3 marked IELp that were most dependent upon Bcl-2 for survival. Importantly, the additional loss of Bim restored Runx3+α4β7+ IELp, showing that Bcl-2 antagonizes Bim to enable IELp survival. Further, the loss of thymic IELp in CD4CreBcl2f/f mice also led to a dramatic loss of IEL in the gut, and the additional loss of Bim restored gut IEL. The loss of gut IEL was due to both reduced seeding by IELp from the thymus as well as a requirement for Bcl-2 for peripheral IEL survival. Together, these findings highlight subset-specific and temporal roles for Bcl-2 in driving the survival of TCRαβ+CD8αα+ IEL and thymic IELp.

Clinical Effect of CD25 on the Prognosis of Diffuse Large B Cell Lymphoma with Secondary Central Nervous System Relapse

In the present study, we investigated the effects of immunophenotyping on prognosis of diffuse large B cell lymphoma (DLBCL) with central nervous system (CNS) relapse treated with rituximab-CHOP (R-CHOP). CNS relapse occurred in 9.5% of DLBCL patients. At the diagnosis of DLBCL, CD25 was detected in 14.3% of cases. CD25 positivity correlated with an advanced stage, higher R-IPI, higher CNS-IPI, the presence of B symptoms, the presence of extranodal involvement >1, and bone involvement. Moreover CNS relapse was more frequently observed in patients with CD25+ than in those with CD25-. The univariate analysis showed that an advanced stage, high-risk R-IPI, high-risk CNS-IPI, bone involvement, and CD25+ were associated with shorter overall survival (OS). The multivariate analysis confirmed that CD25+ and high-risk CNS-IPI were independent adverse prognostic factors for shorter OS. A Kaplan-Meier analysis revealed the potential of CD25+ as a prognostic factor in patients with CNS relapse and that it correlated with shorter survival. The present results showed that the expression of CD25 in DLBCL patients with CNS relapse was associated with the patient prognosis independent other prognostic factors. The establishment of a treatment strategy for CNS relapse patients with CD25+ DLBCL cells is needed to improve poor outcomes.

IL-2/IL-3 interplay mediates growth of CD25 positive acute myeloid leukemia cells

Cell surface interleukin-2 receptor α-chain (IL-2Rα, CD25) expression is currently recognized to be a strong predictor for poor prognosis in patients with acute myeloid leukemia (AML). However, it is still unknown that the reason why CD25 positive AML patients have a dismal clinical outcome. CD25 positive AML cells are generally unresponsive to IL-2, but strongly respond to IL-3. The levels of IL-3Rα on these AML cells are very high and directly proportional to the CD25 levels. T-lymphocytes produce IL-3 in response to stimuli including IL-2-mediated activation. Thus, CD25 on AML cells may capture environmental IL-2 and deliver it to the surrounding T-lymphocytes expressing IL-2Rβ/γc, leading to the production of IL-3 as a growth stimulus to CD25 positive AML cells. We hypothesize that IL-2/IL-3 interplay via CD25 is responsible for the growth property of CD25 positive AML, which may affect clinical behavior of those patients.

Evaluation of CD25-positive cells in relation to the subtypes and prognoses in various lymphoid tumours in dogs

Interleukin-2 receptor alpha chain (CD25) expression has been reported in human lymphoid tumours and suggested to correlate with the prognosis. In this study, we detected CD25-positive cells in various types of lymphoid tumours in dogs. Immunohistochemical analyses of the tissues from diffuse large B-cell lymphoma (DLBCL) (n = 6), T-zone lymphoma (TZL) (n = 5), and follicular lymphoma (FL) (n = 2) revealed that cells strongly positive for CD25 were observed generally in accordance with lymphoma cell localization. CD25-positive cells were consistently detected in TZL and FL cases; however, the number of CD25-positive cells was variable among DLBCL cases. Furthermore, we evaluated the rate of CD25-positive cells by flow cytometric analysis in 29 dogs with lymphoid malignancies, including high-grade B-cell lymphoma (n = 17), TZL (n = 5), FL (n = 2), cutaneous lymphoma (n=2), and acute lymphoblastic leukaemia (ALL) (n = 3). CD25-positivity in the lymph node cells was significantly higher in dogs with high-grade B-cell lymphoma (mean ± SD, 49.6 ± 31.3%) or TZL (mean ± SD, 80.2 ± 10.0%) than that in healthy dogs (mean ± SD, 9.8 ± 2.8%). In prognostic analysis of 15 cases with high-grade B-cell lymphoma, the progression-free survival was significantly shorter in CD25-high group than that in CD25-low group. The results obtained in this study are useful for subtype differentiation and prognostic analysis of canine lymphomas and future development of molecular-targeted therapy directed at CD25.

Interpretation of interleukin-2 receptor alpha positive cells during induction chemotherapy for adult acute myelogenous leukaemia patients

To correlate clinical outcomes with the expression of interleukin-2 receptor alpha (CD25) positive cells during induction chemotherapy (IC) in adult patients with acute myeloid leukaemia (AML), we investigated the prognostic importance of subsets of peripheral blood (PB) CD45+CD25+ cells. Seventy-five patients with newly diagnosed AML received the same initial IC; and serial PB samples were taken. The gated CD45/CD25 cell populations were used to compare the intensity of immunophenotypic signals based on the treatment timeline. Patients who responded poorly to IC demonstrated exceptionally higher levels of PB CD45+CD25+ cells by percentage (p = 0.003) or by absolute count (p = 0.046) on the seventh day (D + 7) of initial IC. In addition, patients in complete remission (CR) (n = 61) demonstrated relatively lower levels of steady PB CD45+CD25+ after standard IC. These results suggest that the expression of CD25 can be used to predict the response to IC during an early period of treatment.

Elevated levels of soluble interleukin-2 receptor in serum of patients with hematological or non-hematological malignancies

We measured the levels of soluble interleukin-2 receptor (sIL-2R) in the serum of 53 patients with hematological malignancies (14 with acute leukemia, 10 myeloproliferative disorders, 21 non-Hodgkin's lymphoma and 8 multiple myeloma), 40 with non-hematological solid malignancies (24 with lung cancer, 11 digestive system cancer and 5 other cancers) and 95 healthy subjects as a control using an enzyme-linked immunosorbent assay. Both hematological and non-hematological neoplasms showed significantly higher sIL-2R levels than normal subjects (p<0.01). However, compared to solid malignancies, hematological neoplasms displayed a wide range of sIL-2R levels and extremely elevated values of sIL-2R were seen in certain cases. These results seem to suggest that sIL-2R levels may serve as one of non-invasive markers of differential diagnosis for patients with bulky mass lesions between hematological and solid malignancy.

Induction of cell surface interleukin 2 receptor alpha chain expression on non-T lymphoid leukemia cells

We examined nine cases of adult non-T lymphoid leukemia to investigate the cell surface inducibility of interleukin 2 receptor alpha chain (IL-2R alpha) and beta chain (IL-2R beta) after in vitro culture with and without recombinant human interleukin-1 beta (rhIL-1 beta). Induction of IL-2R alpha was observed in four of six cases with precursor B-cell acute lymphoblastic leukemia (pre-B ALL) and in all of three cases with B-cell mature lymphoid neoplasm (two chronic lymphocytic leukemia and one leukemic phase of non-Hodgkin's lymphoma). All of the IL-2R alpha-inducible cases could express this spontaneously even without rhIL-1 beta, while IL-2R beta did not appear on leukemic cells from any of the cases tested. IL-2R alpha-inducible pre-B ALL cases displayed stem cell antigen CD34 and induced myeloid-associated antigen CD13 simultaneously. These results suggest that IL-2R alpha but not IL-2R beta is easily inducible in certain cases of mature B-cell lymphoid neoplasm and pre-B ALL with immature characteristics.