View clinical trials related to Immune Tolerance.
Filter by:The investigators want to investigate whether specific immunotherapy can be delivered directly into a lymph node. The investigators think that a direct introduction of allergen to the antigen presenting cells in the lymph node a give a strong immune response and that this can change the number of injections needed in allergen immunotherapy. The investigators do measurements of clinical effect and a variety of paraclinical test to see if the investigators can find af biomarker of successful specific immune therapy of grass allergy.
Many authors propose the strict avoidance of allergenic food as the only treatment for children known to be allergic to certain food. However, it has been observed an increase of the frequency and severity of the allergic accidents in these children in the long term. Other teams have suggested treating these allergies (in particular peanut allergies) by controlled and progressive reintroduction of the allergenic food. A good tolerance and a prevention of allergic reactions consecutive to the ingestion of the same allergenic food were observed. The immunological mechanisms of this type of treatment are not well known. A decrease of specific IgE and an increase of IgG4 have been observed in the case of egg allergies after this kind of treatment. Certain experiments realized in mice models testing the allergenic stimulation challenge showed an increase of lymphocytes T regulators (foxp3+ , CD4+, CD25+), stimulated by dendritic cells, and also an increase of interleukin 10, leading to the modification of the balance between Th1 and Th2.Our hypothesis is that after treating allergies by the reintroduction of the allergenic food, the immunological mechanism of acquisition of tolerance is associated to variations in populations of lymphocytes and in the activation or decrease of pro and anti-inflammatory cytokines. This reaction will be studied in two groups: 1. Children with a confirmed allergy to peanuts or nuts and 2. Children without antecedents of allergy or familiar atopy.
In this pilot study the investigators aim to investigate the effects of vitamin D supplementation on regulatory FoxP3+ T cells in the gastrointestinal mucosa in healthy women and men.
Recently, controversy has emerged regarding the role of the 23vPPV in infants due to potential immunological hypo-responsiveness (i.e. a poorer immune response to repeat vaccination). Although previous experience of 23vPPV in children in PNG has demonstrated protective efficacy against acute lower respiratory tract infection, the investigators feel it is a matter of urgency to determine if 23vPPV administration provides elevated antibody concentrations at 3 to 5 years of age, and to ensure the immunological safety of the 23vPPV in infants. Following consent and eligibility assessment, a baseline blood sample and nose swab will be taken, a 0.1ml dose of 23vPPV will be administered and a follow up blood sample and nose swab will be collected 28 days later. The investigators will also collect data on incidence of ALRI in all study participants by medical record review.
Patients with obstructive jaundice (OJ) often require surgical, endoscopic or radiological interventions to facilitate biliary drainage and relieve jaundice. However it is known that patients with OJ have increased surgical risks than non-jaundiced patients undergoing the same procedures. Surgery for severe OJ is associated with a significant post-operative mortality (10-15%) and morbidity (30-65%). The commonest complications are related to sepsis but the pathophysiological mechanisms behind this susceptibility to bacterial infection are not clear. Recent work has shown a pivotal role of bile in the maintenance of enterocyte tight junctions and the expression of tight junction-associated proteins which could account for the translocation of enteric bacteria and bacterial products to mesenteric lymph node complexes, the portal circulation and subsequently the liver. Some of these bacterial products, such as endotoxin and quorum sensing signalling molecules (QSSMs), have immunomodulatory properties which may dampen normal immune responses to infection resulting in life-threatening organ dysfunction. Bacterial endotoxin and quorum sensing signalling molecules (QSSMs) represent good candidates for the mediators of this immune suppression and although there is a compelling case for their involvement in the pathogenesis of sepsis, evidence to support their involvement in the aetiology of infection in OJ is currently lacking.
Infection accounted for the first cause of death in patients after liver transplantation, and 2 / 3 of the cause of death was fungal infections. The investigators group early found that T cell subsets playing a role of inducing immune tolerance were significantly increased in vivo of liver transplantation patients with aspergillus infection, which may be a kind of Treg cells expressing IL-17. To explore the immune tolerance mechanism induced by the immune balance cells is important to liver transplantation patients for improving efficacy and reducing the mortality. Therefore, the investigators are going to get the blood sample and liver tissue of the liver transplantation patients before and after treatment of aspergillus infection, flow cytometry analysis of blood T cell subsets, Cytometric Bead Array to detect changes in blood cytokines, laser capture microdissection to obtain liver biopsies of inflammatory cells in portal area and further for analysis of T cell subsets and protein. And the investigators are also to investigate the characteristics of CCR6 + CD4 + FOXP3 + Treg cell clones secreting IL-17 and the capacity of which suppressing conventional T cell proliferation. This study may find new methods, such as certain types of T cell subsets or cytokines for the treatment of liver transplant patients, which not only to anti-rejection but also to reduce fungal infection.
The Stanford Medical Center Program in Multi-Organ Transplantation and the Division of Bone Marrow Transplantation are enrolling patients into a research study to determine if blood stem cells injected after kidney transplantation, in combination with lymphoid irradiation ,will change the immune system such that immunosuppressive drugs can be completely withdrawn. Patients must have a healthy, completely human leukocyte antigen (HLA)-matched brother or sister as the organ and stem cell donor. One to two months before kidney transplant surgery, blood stem cells will be removed from the donor and the cells will be frozen. After transplant surgery, the recipient will receive radiation and anti-T cell antibody treatments for two weeks to prepare for injection of the stem cells. The stem cells will be injected at the end of the two-week treatment. If the stem cells persist in the recipient, immunosuppressive drugs will be gradually reduced until they are withdrawn completely at least six months after transplantation. Patients will be followed in the Stanford clinics for transplant patients. Patients who live outside of the San Francisco Bay Area must remain near Stanford for six weeks after transplant surgery.