Regulatory T cells (Treg) are functionally mature T cell subpopulations which are key players of maintaining the balance of immunological defense system. Treg can proliferate in vivo or in vitro by antigen specific way or non-antigen specific way, and actively control the properties of other immune cells by suppressing their functional activity and their proliferation as well.
Humans ; Immune Tolerance ; T-Lymphocytes, Regulatory ; immunology

It has been demonstrated that severe burn per se may contribute to activation and proliferation of regulatory T cells (Treg). This characteristic phenomenon might allow Treg to function for a prolonged period of time to regulate immune response, and to induce suppression of T lymphocyte immune function. Different degrees of elevated levels of cytokines produced by Treg and activation markers on Treg surface could also be involved in the development of sepsis and fatal outcome in patients with severe burn. Thus, the regulation of Treg as a cellular therapeutic strategy might be important to the Th1/Th2 cytokine balance in burn patients complicated with sepsis.
Burns ; immunology ; Humans ; Sepsis ; immunology ; T-Lymphocytes, Regulatory ; immunology

Humans ; Lung ; immunology ; Pulmonary Fibrosis ; immunology ; T-Lymphocytes, Regulatory ; immunology

It is now established that CD4(+)CD25(+)regulatory T (Treg) cells expressing transcription factor FOXP3, a regulatory subpopulation of T cells, is indispensable for the maintenance of immunological self-tolerance and immune homeostasis. FOXP3 expression in Treg cells is specific and it is the key control factor for the development, activation and function of Treg cells. At present, CD4(+)FOXP3(+)T lymphocytes are often used to define Treg cells for scientific research. But recent studies show that human CD4(+)FOXP3(+)T cells are phenotypically and functionally heterogeneous, including suppressive and non suppressive T cells. The different functions of these cell subsets can be distinguished by phenotypic differences. This review discusses the recent research progress about phenotypic characteristics and functional heterogeneity of CD4(+)FOXP3(+)T cell subsets.
Forkhead Transcription Factors ; immunology ; Humans ; T-Lymphocytes, Regulatory ; immunology

There has been a history of 30 years in the study of CD4(+)CD25(+) T regulatory cells (Treg) which primarily play a role of immune suppression in vivo. Many autoimmune diseases are related to the decrease and the disorder of these cells, such as multiple sclerosis, non-obese diabet (NOD) and lupus erythematosus. In the field of transplantation tolerance, the role played by Treg is also very important. All of these features have drawn the attention to the prevention of autoimmune diseases and the rejection of transplantation. However, the low frequency of Treg in vivo affected their use and study. Currently, many techniques about expansion of Treg in vitro have been established so as to overcome the problem of their limited cell numbers in vivo. Recent studies suggest that antigen-specific T regulator cells (sTreg) expanded by dentritic cells (DC) showed a superior immunosuppression in comparison with polyclonal Treg expanded by anti-CD3/CD28Ab, which is the focus of current studies. This article mainly reviews and compares the expansion techniques and the mechanism of regulatory T cells.
Cell Culture Techniques ; Humans ; Immunosuppression ; T-Lymphocytes, Regulatory ; cytology ; immunology

Humans ; Pleural Effusion ; etiology ; immunology ; T-Lymphocytes, Regulatory ; physiology

γδ T cells display unique developmental, distributional, and functional patterns and can rapidly respond to various insults and contribute to diverse diseases. Different subtypes of γδ T cells are produced in the thymus prior to their migration to peripheral tissues. γδ T cells are enriched in the liver and exhibit liver-specific features. Accumulating evidence reveals that γδ T cells play important roles in liver infection, non-alcoholic fatty liver disease, autoimmune hepatitis, liver fibrosis and cirrhosis, and liver cancer and regeneration. In this study, we review the properties of hepatic γδ T cells and summarize the roles of γδ T cells in liver diseases. We believe that determining the properties and functions of γδ T cells in liver diseases enhances our understanding of the pathogenesis of liver diseases and is useful for the design of novel γδ T cell-based therapeutic regimens for liver diseases.
Animals ; Cytokines ; immunology ; Humans ; Liver Diseases ; immunology ; Liver Regeneration ; immunology ; Mice ; T-Lymphocytes, Regulatory ; immunology

Various cell types that express regulatory function may influence the pathogenesis of most and perhaps all infections. Some regulatory cells are present at the time of infection whereas others are induced or activated in response to infection. The actual mechanisms by which different types of infections signal regulatory cell responses remain poorly understood. However a most likely mechanism is the creation of a microenvironment that permits the conversion of conventional T cells into cells with the same antigen specificity that have regulatory function. Some possible means by which this can occur are discussed. The relationship between regulatory cells and infections is complex especially with chronic situations. The outcome can either be of benefit to the host or damage the disease control process or in rare instances appears to be a component of a finely balanced relationship between the host and the infecting agent. Manipulating the regulatory cell responses to achieve a favorable outcome of infection remains an unfulfilled objective of therapeutic immunology.
Allergy and Immunology ; Communicable Diseases* ; Sensitivity and Specificity ; T-Lymphocytes ; T-Lymphocytes, Regulatory*

OBJECTIVETo investigate the changes and roles of follicular regulatory T cells (Tfr) and follicular T helper cells (Tfh) in the pathogenesis of children immune thrombocytopenia (ITP).

METHODS32 untreated ITP patients, as well as 20 healthy controls were enrolled in this study. The proportion of circulating Tfr and Tfh cells were determined by flow cytometry; real-time PCR was performed to detect the expression of transcription factors and regulatory factors of Bcl-6, c-Maf, Blimp-1 and PD-1 mRNA; ELISA was used to detect plasma concentration of IL-2, IL-6, IL-10 and IL-21.

RESULTS(1)The proportion of Tfh cells were significantly higher (P<0.05), while the Tfr cells and the ratio of tfr/Tfh cells in ITP patients were significantly lower than that in health controls (P<0.05); (2)Correlation analysis showed that the Tfr cells and the ratio of Tfr/Tfh were positively correlated with the platelet counts and negatively with the levels of PA-IgG, while the proportion of Tfh cells was positively correlated with the levels of PA-IgG and negatively with the platelet counts in peripheral blood; (3)Transcription levels of Bcl-6 and c-Maf mRNA in CD4(+) T lymphocytes cells were significantly elevated, the Blimp-1 mRNA in CD4(+) cells and PD-1 mRNA levels of Treg were lower in ITP patients in comparison with healthy controls; (4)The higher Plasma concentration of IL-21, and lower concentration of IL-2 were found in ITP patients.

CONCLUSION(1)The lower proportion of Tfr cells and higher proportion of Tfh cells, as well as the abnormal ratio of Tfr/Tfh might account for the decreased platelet counts to be further involved in the immunological pathogenesis of children ITP; (2)The changes of plasma cytokines IL-2, IL-21 in microenvironment and the over-expression of Bcl-6 mRNA, c-Maf mRNA and the lower-expression of Blimp-1 mRNA in CD4(+) T cells, and over-expression of PD-1 mRNA in Treg cells might be account for the abnormal ratios of Tfr/Tfh cells in ITP patients.

T cell immunity and phagocytic activity were studied in the blood of patients with IgA nephropathy in order to clarify their roles in the pathogenesis of IgA nephropathy. The percentages of total T lymphocytes, helper T cell and suppressor T cells were significantly reduced in patients. A significantly elevated helper T cell/suppressor T cell ratio in patients showed a predominant reduction in suppressor T cells. There was a significant relationship between histologic findings and helper T cell/suppressor T cell ratio in patients. Natural Killer (NK) cell activity was significantly reduced but the lymphocyte response after phytohemagglutinin (PHA) stimulation was not in patients. ConA-induced suppressor cell activity was not depressed despite of a decrease in suppressor T cells in patients. Phagocytic activity of polymorphonuclear leucocytes (PMNs) ingesting yeasts was significantly reduced in patients. Also an inverse correlation was found between serum IgA levels and phagocytic activity of PMN. It is concluded that suppressor T cell defects, depressed phagocytic activity and impaired NK cell activity may play a role in the pathogenesis of IgA nephropathy.
B-Lymphocytes/immunology ; Glomerulonephritis, IGA/*immunology/pathology ; Humans ; Killer Cells, Natural/immunology ; Neutrophils/immunology ; *Phagocytosis ; T-Lymphocytes/*immunology ; T-Lymphocytes, Regulatory/immunology