CD4⁺ CD25^bright regulatory T (T_reg) cells have been identified as a principle regulator of tolerance during pregnancy. In the setting of pre-eclampsia, however, little is known about the dynamics of these cells. In the current study, we determined CD4⁺ CD25^bright T_reg cells in the peripheral blood using flow cytometry and forkhead box P3 (FoxP3⁺) cells at the placental bed using immunohistochemical staining. Peripheral blood mononuclear cells (PBMC) of 38 pre-eclamptic cases (17 cases Japanese, 21 cases Polish), 40 normal late pregnancy subjects (20 subjects Japanese, 20 subjects Polish), and 21 non-pregnant healthy controls (10 subjects Japanese, 11 subjects Polish) were included. We found the percentage of CD25^bright cells within the CD4⁺ T cell population in PBMC was reduced significantly in both Japanese and Polish pre-eclamptic cases than in normal pregnancy subjects (P < 0·001) and non-pregnant healthy controls (P < 0·001). Also, the percentage of FoxP3⁺ cells within CD3⁺ T cells in the placental bed biopsy samples of pre-eclamptic cases were decreased compared to those in normal pregnancy subjects. These findings suggest that a decreased number of T_reg cells was present in pre-eclampsia, and these changes might break the maternal tolerance to the fetus.

Myeloid-derived suppressor cells (MDSC) contribute to immune suppression in cancer, but the mechanisms through which they drive metastatic progression are not fully understood. In this study, we show how MDSC convey stem-like qualities to breast cancer cells that coordinately help enable immune suppression and escape. We found that MDSC promoted tumor formation by enhancing breast cancer cell stem-like properties as well as by suppressing T-cell activation. Mechanistic investigations indicated that these effects relied upon cross-talk between the STAT3 and NOTCH pathways in cancer cells, with MDSC inducing IL6-dependent phosphorylation of STAT3 and activating NOTCH through nitric oxide leading to prolonged STAT3 activation. In clinical specimens of breast cancer, the presence of MDSC correlated with the presence of cancer stem-like cells (CSC) and independently predicted poor survival outcomes. Collectively, our work revealed an immune-associated mechanism that extrinsically confers cancer cell stemness properties and affects patient outcome. We suggest that targeting STAT3-NOTCH cross-talk between MDSC and CSC could offer a unique locus to improve cancer treatment, by coordinately targeting a coupled mechanism that enables cancer stemness and immune escape. Cancer Res; 76(11); 3156–65. ©2016 AACR.

This review of literature attempts to identify the factors that are involved in the pathogenesis of Hashimoto thyroiditis, an immune defect in an individual with genetic susceptibility accompanied with environmental factors. The frequency of Hashimoto’s disease is a growing trend and among Caucasians it is estimated at approximately 5%. The dysfunction of the gland may be clinically evident (0.1–2% of the population) or subclinical (10–15%). The pathology is diagnosed five to ten times more often in women than men and its incidence increases with the age (the peak of the number of cases is between 45 and 65); however, it can also be diagnosed in children. The pathogenesis of Hashimoto’s thyroiditis is still not fully comprehended. In the etiology of Hashimoto thyroiditis excessively stimulated T CD4+ cells are known to play the most important role. Recent research has demonstrated an increasing role of newly discovered cells such as Th17 (CD4+IL-17+) or T regulatory cells (CD4+CD25+highFoxP3+) in the induction of autoimmune disorders. The process of programmed cell death also plays an equally important role in the pathogenesis and the development of hypothyroidism.

Foxp3⁺CD4⁺ regulatory T (Treg) cells inhibit immune responses and temper inflammation. IL-17⁺CD4⁺ T (Th17) cells mediate inflammation of autoimmune diseases. A small population of IL-17⁺Foxp3⁺CD4⁺ T cells has been observed in peripheral blood in healthy human beings. However, the biology of IL-17⁺Foxp3⁺CD4⁺ T cells remains poorly understood in humans. We investigated their phenotype, cytokine profile, generation, and pathological relevance in patients with ulcerative colitis. We observed that high levels of IL-17⁺Foxp3⁺CD4⁺ T cells were selectively accumulated in the colitic microenvironment and associated colon carcinoma. The phenotype and cytokine profile of IL-17⁺Foxp3⁺CD4⁺ T cells was overlapping with Th17 and Treg cells. Myeloid APCs, IL-2, and TGF-β are essential for their induction from memory CCR6⁺ T cells or Treg cells. IL-17⁺Foxp3⁺CD4⁺ T cells functionally suppressed T cell activation and stimulated inflammatory cytokine production in the colitic tissues. Our data indicate that IL-17⁺Foxp3⁺ cells may be “inflammatory” Treg cells in the pathological microenvironments. These cells may contribute to the pathogenesis of ulcerative colitis through inducing inflammatory cytokines and inhibiting local T cell immunity, and in turn may mechanistically link human chronic inflammation to tumor development. Our data therefore challenge commonly held beliefs of the anti-inflammatory role of Treg cells and suggest a more complex Treg cell biology, at least in the context of human chronic inflammation and associated carcinoma.

Glioblastoma (GBM) is the most popular primary central nervous system cancer and has an extremely expansive course. Aggressive tumor growth correlates with short median overall survival (OS) oscillating between 14 and 17 months. The survival rate of patients in a three-year follow up oscillates around 10%. The interaction of the proteins programmed death-1 (PD-1) and programmed cell death ligand (PD-L1) creates an immunoregulatory axis promoting invasion of glioblastoma multiforme cells in the brain tissue. The PD-1 pathway maintains immunological homeostasis and protects against autoimmunity. PD-L1 expression on glioblastoma surface promotes PD-1 receptor activation in microglia, resulting in the negative regulation of T cell responses. Glioblastoma multiforme cells induce PD-L1 secretion by activation of various receptors such as toll like receptor (TLR), epidermal growth factor receptor (EGFR), interferon alpha receptor (IFNAR), interferon-gamma receptor (IFNGR). Binding of the PD-1 ligand to the PD-1 receptor activates the protein tyrosine phosphatase SHP-2, which dephosphorylates Zap 70, and this inhibits T cell proliferation and downregulates lymphocyte cytotoxic activity. Relevant studies demonstrated that the expression of PD-L1 in glioma correlates with WHO grading and could be considered as a tumor biomarker. Studies in preclinical GBM mouse models confirmed the safety and efficiency of monoclonal antibodies targeting the PD-1/PD-L1 axis. Satisfactory results such as significant regression of tumor mass and longer animal survival time were observed. Monoclonal antibodies inhibiting PD-1 and PD-L1 are being tested in clinical trials concerning patients with recurrent glioblastoma multiforme.