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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Over a period of 5 years, lymphocyte subpopulations and their markers of activation were studied prospectively in 56 first degree relatives of Type 1 (insulin-dependent) diabetic probands. Lymphocytes were phenotyped using a panel of monoclonal antibodies which recognise CD3, CD4, CD8 lymphocytes, K/NK cells, HLA Class II products and IL-2 receptors (IL-2r). Twenty-six subjects were negative for islet cell antibody (ICA), 18 had complement fixing ICA (CF-ICA) and 12 only conventional ICA (ICA-IgG). The total number of observations (blood samples collected) was 386. Overall, changes in T cell data were observed in the three groups of first degree relatives compared to 70 normal subjects without a family history of diabetes. Six individuals developed Type 1 diabetes in the course of the study. They all possessed CF-ICA and five out of six showed a persistent reduction (less than 1.5) of the CD4/CD8 lymphocyte ratio before the clinical onset of the disease. Activated lymphocytes were found on two occasions in two of these subjects. We conclude that imbalance of lymphocyte immunoregulatory subsets is present before the onset of Type 1 diabetes in susceptible individuals; the persistence of a reduced CD4/CD8 lymphocyte ratio may reflect the ongoing process leading to B-cell destruction.
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PMID:Persistent reduction of CD4/CD8 lymphocyte ratio and cell activation before the onset of type 1 (insulin-dependent) diabetes. 250 62

Diabetes susceptibility in non-obese diabetic (NOD) mice may entail faulty activation of immunoregulatory cells resulting from cytokine deficiencies. Depletion of T cells prevents disease onset in these mice. Since we had previously shown that IL-2 treatment in vivo restored the ability of NOD/Lt mice to produce self-restricted suppressor T cells (Ts) in a syngeneic mixed lymphocyte reaction (SMLR), we investigated the possibility that diabetes could be circumvented by treatment with immunostimulatory agents that increase cytokine production. By 20 weeks of age, 75% of vehicle-treated NOD/Lt female controls had become glycosuric, while glycosuria developed in only 17% of NOD/Lt females injected with human recombinant interleukin-2 (rIL-2, 250 U twice weekly) beginning at 6 weeks of age. Treatment of mice with Poly [I:C] alone [50 micrograms twice weekly, an inducer of Interferon (IFN) alpha/beta] or in conjunction with rIL-2 was even more effective, completely preventing glycosuria for 20 weeks. However, therapeutic effects required continuous administration of the immunostimulants since pancreatic insulin content declined and severity of insulitis increased following cessation of treatment. IL-2 treatment increased transcription of interleukin-1 (IL-1) mRNA in peritoneal macrophages and increased lipopolysaccharide (LPS)-stimulated IL-1 secretion in comparison to controls. In the presence of stimulators from IL-2-treated mice, T lymphocytes isolated from both controls and IL-2-treated NOD/Lt mice proliferated in a SMLR and acquired Ts function. Peritoneal macrophages from Poly [I:C]-treated mice exhibited increased IFN alpha gene transcription and LPS-stimulated IL-1 secretion. T cells isolated from Poly [I:C]-treated mice were capable of suppressing NOD-Lt T cell responses to alloantigens in a mixed lymphocyte culture without prior activation in a SMLR. Thus, Poly [I:C] treatment may recruit a different population of regulatory cells than those elicited by treatment with IL-2. However, the mechanisms by which autoreactive T-cell clones may be regulated by these two treatments in NOD/Lt mice may be synergistic. These results indicate that in addition to T-cell depletion protocols, diabetes in NOD mice can be prevented by treatment with immunostimulatory agents.
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PMID:Immunostimulation circumvents diabetes in NOD/Lt mice. 253 2

The question is still unresolved whether in insulin-dependent (type I) diabetes T-lymphocytes mediate an autoimmune response towards pancreatic islets. We now present direct evidence in an animal model for autoimmune T-lymphocytes with specificity for islet antigens. Mice of strain C57BL/6 were immunized repeatedly with islet homogenates. Lymphocytes isolated from draining lymph nodes and the spleen show a specific proliferative response when challenged with mouse rat or islet antigens but do not respond to liver or spleen antigens. Islet antigen specific lymphoblasts have been maintained by in vitro culture for several weeks in the presence of T-cell growth factor containing medium.
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PMID:Autoimmune T-lymphocytes with specificity for pancreatic islet antigens. 258 Jul 80

Although convincing evidence has been obtained for the imposition of self-tolerance by the intrathymic deletion of self-reactive T cells, the development of tolerance to antigens which are expressed only in the periphery is not so well understood. We have approached this question by creating transgenic mice which carry a class I major histocompatibility complex (MHC) gene (H-2Kb) linked to the rat insulin promoter. Mice expressing the transgene develop diabetes, but do not appear to mount an immune response against the transgene-expressing pancreatic beta-cells, even when the transgene is allogeneic with respect to the endogenous host H-2 antigens. We have now explored the mechanism of this tolerance further. We find that spleen cells from pre-diabetic transgenic (RIP-Kb) mice do not kill targets bearing H-2Kb, whereas thymus cells from the same mice do. The unresponsiveness of these spleen cells can be reversed in vitro by providing recombinant interleukin-2 (rIL-2). In older, diabetic mice, responsiveness develops as the pancreatic beta-cells are lost. Our results point to an extrathymic mechanism of tolerance induction, dependent on the continuous presence of antigen and the lack of IL-2 in the local environment of potentially reactive T cells.
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PMID:Tolerance of class I histocompatibility antigens expressed extrathymically. 278 8

Nonobese diabetic (NOD) is an inbred mouse strain susceptible to development of T cell-mediated autoimmune diabetes. The strain is characterized by high percentages of T lymphocytes in lymphoid organs. The syngeneic mixed lymphocyte reaction (SMLR), a T cell response to self MHC class II Ag, is reportedly involved in the generation of a number of immunoregulatory cells, including suppressor inducers. A severely depressed SMLR characteristic of certain other autoimmune strains was found in NOD but not in nonautoimmune SWR/Bm mice. Moreover, IL-2 produced by NOD T cells at day 6 in an SMLR was at least one hundredfold reduced compared with SWR, and NOD T cells harvested from an SMLR at day 6 were functionally defective when tested for ability to induce suppression of an allogeneic MLR. However, functionally competent suppressor T cells were generated in NOD splenic leukocyte cultures in response to Con A, and IL-2 release from these was equivalent to that released by Con A-stimulated SWR splenocytes. A deficiency in cytokine release was not limited to IL-2, because peritoneal exudate cells from NOD exhibited a greatly diminished sensitivity to LPS-stimulated IL-1 release in comparison to SWR mice. IL-2 supplementation both in vitro and in vivo restored the ability of NOD T cells to respond in a SMLR, with production of cells capable of inducing suppression. Like SMLR-activated T cells from untreated SWR controls, SMLR blasts from IL-2-treated NOD mice were enriched for the L3T4 phenotype. IL-1 supplementation in vitro resulted in partial restoration of T suppressor activation in a SMLR. The depressed SMLR exhibited by NOD mice was apparently a stimulator cell dysfunction, because NOD stimulator cells failed to activate T cells from (SWR x NOD)F1 mice, whereas stimulators from SWR or F1 mice were capable of doing so. Collectively, these results suggest a defect in suppressor cell activation rather than an absence of this immunoregulatory cell population.
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PMID:Defective activation of T suppressor cell function in nonobese diabetic mice. Potential relation to cytokine deficiencies. 289 95

Peripheral blood mononuclear cells from patients with Type 1 diabetes mellitus were examined for the proportion of monoclonal antibody-defined T-cell subsets, natural killer (NK) cells, and macrophages and the proliferative response to phytohemagglutinin (PHA), Concanavalin A (Con A), pokeweed mitogen (PWM) and in the autologous mixed lymphocyte reaction (AMLR) and allogeneic mixed lymphocyte reaction (MLR). The in vitro response of purified IL-2 on PHA- and PWM-induced proliferative response was also examined. Total T cells (Leu 1+), helper/inducer phenotype (Leu 3+) T cells, suppressor/cytotoxic phenotype (Leu 2+) T cells, surface Ig+ B lymphocytes and monoclonal antibody-defined monocytes (Mac +) in patient group were comparable to the control group. The Leu 7+ NK cells were, however significantly (p less than 0.05) decreased in the diabetic group. The NK function was also deficient in the diabetic group when compared to healthy non-diabetic controls. The proliferative responses to all 3 concentrations of PHA, PWM, and Con A, and in the MLR were similar in 2 groups. However, the proliferative response in the AMLR was significantly reduced (p less than 0.05) in the diabetic group. Exogenous purified IL-2 failed to induce any enhancement in the PHA- and PWM-induced proliferative response; this was in contrast to control group in which IL-2 enhanced proliferative response to both mitogens. This study demonstrates deficiency of the AMLR, Leu 7+ and of natural killer cell function and unresponsiveness of mitogen-activated T cells to purified IL-2. The significance of these findings is discussed.
Diabetes Res 1986 Jun
PMID:Multiparameter immunologic studies in patients with newly diagnosed type 1 insulin-dependent diabetes mellitus. 294 47

We studied autologous mixed leukocyte reaction (AMLR) in type 1 (insulin-dependent) diabetes mellitus (IDDM) patients, their healthy siblings and healthy schoolchildren, Blood samples from the patients were drawn within 1 week after hospitalization and 2 months later. AMLR was significantly depressed in the patients when compared to healthy siblings or other healthy controls. In addition, the mean AMLR responsiveness of the healthy control group exceeded that of healthy siblings. The production of IL-2 in AMLR was impaired in the patient group and the defective AMLR could be restored by addition of exogenous IL-2 in 7-10 patient cultures. However, in 3-10 patients addition of IL-2 induced no enhancement of proliferation. While the patients in general had raised levels of activated T lymphocytes these three patients had higher numbers of activated T cells than other patients. Defective AMLR and presence of activated T cells may be related and may play a role in the pathogenesis of IDDM.
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PMID:Defective autologous mixed leukocyte reaction in newly diagnosed type 1 diabetes mellitus. 296 3

Previous studies have shown several immunoregulatory abnormalities in insulin-dependent diabetes mellitus (IDDM). In this report we compared peripheral blood mononuclear cells (PBMC) from patients with IDDM complicated by end-stage renal disease (ESRD) to those from normal subjects and from patients with ESRD of different etiologies for their: natural killer (NK) and antibody-dependent cell-mediated cytotoxic (ADCC) activities; modulation of NK and ADCC activities by biological response modifiers (BRM) including purified human lymphoblastoid interferon, human recombinant alpha-2 interferon, human gamma interferon and human recombinant interleukin 2; proliferative response of T and B lymphocytes to concanavalin A (Con A), phytohemagglutinin and pokeweed mitogen, and ability to produce T-cell growth factor (interleukin 2; IL-2). PBMC of diabetic patients demonstrated significantly lower NK activity than normal and ESRD subjects. Upon treatment with BRM, NK activity was augmented and achieved normal levels. ADCC activity was not different from that of normal controls and exhibited similar increases when stimulated by BRM. The proliferative responses to Con A, phytohemagglutinin and pokeweed mitogen as well as IL-2 production in response to Con A stimulation were significantly lower in the IDDM group. Our results indicated that NK cells from patients with IDDM can respond to IL-2 with enhanced cytotoxicity, and, because activation of resting T cells by mitogenic stimuli depends on the production of IL-2 as well as the appearance of a receptor for IL-2, our finding of low levels of in vitro IL-2 production by PBMC from patients with IDDM may explain the depressed NK activity and the observed poor response to T-cell mitogens.
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PMID:Cell-mediated immunity and biological response modifiers in insulin-dependent diabetes mellitus complicated by end-stage renal disease. 311 74

An assay was developed to detect the cytotoxic effects of cytokines on rat pancreatic islet cells in monolayer culture. Cell lysis was detected by a 51Cr-release assay after 4 days of incubation with various cytokines. When tested alone, murine (rat and mouse) interferon-gamma (mIFN-gamma) produced a small dose-dependent lysis of islet cells; human IFN-gamma, mouse IFN-alpha/beta, interleukins 1 and 2 (IL-1 and IL-2), tumor necrosis factor (TNF), and lymphotoxin (LT) were inactive. When added together, the following combinations of cytokines showed synergistic cytotoxic effects: TNF (or LT) plus IL-1, TNF (or LT) plus mIFN-gamma, and IL-1 plus mIFN-gamma. These results indicate that the cytokine products of mononuclear cells of the immune system, IFN-gamma, TNF, LT, and IL-1 have strong synergistic cytotoxic effects on islet cells and therefore may act as direct chemical mediators of islet beta-cell destruction in type I (insulin-dependent) diabetes.
Diabetes 1988 Jan
PMID:Destruction of rat islet cell monolayers by cytokines. Synergistic interactions of interferon-gamma, tumor necrosis factor, lymphotoxin, and interleukin 1. 312 15

Recently, the presence of a soluble form of IL-2 receptor (IL-2RS) in human sera and in supernatants of PHA-stimulated lymphocytes has been demonstrated. It has been suggested that autoimmune diseases could be characterized by a defect in production of IL-2RS, unlike immunoproliferative disorders which are characterized by overproduction. Our aim was to investigate serum IL-2RS levels in 35 newly diagnosed Type 1 diabetic patients, in 25 age-matched healthy blood donors and in five patients with Hodgkin's disease. We found that newly diagnosed diabetic patients have higher IL-2RS levels (424.8 +/- 203 U/ml) than normal controls (252.4 +/- 38.4 U/ml) (p less than 0.005). In 22 out of 35 patients (62.8%) the IL-2RS values were above the higher 95% tolerance limit of controls. Furthermore, the persistence of high IL-2RS levels was observed in 18/35 diabetic patients six months after diagnosis (470 +/- 195.6 U/ml). The increased levels were not correlated with glycaemic and HbA1c levels and patients' age. Our findings suggest a potentially significant role for the released IL-2R in the regulation of IL-2 dependent lymphocyte functions in Type 1 diabetes. The study of IL-2RS in Type 1 diabetes may provide a new tool for the knowledge of cytokine involvement in the disease.
Diabetes Res 1988 Jul
PMID:Increased soluble interleukin-2 receptor levels in the sera of type 1 diabetic patients. 326 1


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