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C Thivolet

Publications and source records attributed to C Thivolet.

At least 73 records · Page 4Linked to original sources
PubMed1994

Oral administration of human insulin to NOD mice generates CD4+ T cells that suppress adoptive transfer of diabetes.

Oral administration of porcine insulin has been shown to be effective in preventing the spontaneous occurrence of diabetes in the Non-Obese Diabetic (NOD) mouse model. In the present study, we demonstrate that feeding 6-week-old female mice with 20 units of human insulin every 2-3 days for 30 days induces an active mechanism of suppression through the generation of regulatory T cells. Adult irradiated NOD males i.v. injected with 5 x 10(6) T cells from the spleens of diabetic female donors and the same number of T cells from the spleens of insulin-fed animals had less successful diabetes transfer than controls (4/15 vs. 8/16, P < 0.001). Protection from clinical diabetes was associated with a reduction in severe insulitis (16.4 +/- 3.6% vs. 52.3 +/- 12.8%, P = 0.023). However, more than 85% of the islets were inflamed. Feeding animals for 15 days reduced the magnitude of this protection since the number of successful transfers after 1 month was comparable (12/17 vs. 14/17) despite a significant delay in diabetes onset (P < 0.001). No difference in the contribution of T cell subsets was noted by cytofluorometry in the spleens of treated animals. When T cell subsets from insulin-fed animals were co-injected with diabetogenic T cells, only purified CD4+ T cells were able to transfer protection since only 3/12 mice became diabetic after 36 days in comparison to 3/6 in the group co-injected with CD4+ T cells from PBS-fed animals, or 5/6 in the group injected with CD8+ T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Is prevention of type I diabetes mellitus feasible?].

Since the clinical onset of Type 1 diabetes is preceded by an asymptomatic period or prediabetes identified by specific immunogenetic markers, it is possible to imagine specific ways to prevent the onset of the disease in high risk individuals. Such trials will concern mainly first-degree relatives of diabetic patients enrolled into screening programs. The number of individuals necessary to be included in these trials will be function of the therapeutic goals and on the efficacy of the drug in pilot studies in high risk individuals, namely ICA positive subjects with low first phase insulin release during IVGTT. The predominant role of cellular immunity is illustrated in the NOD mouse by the preventive effects of treatments directed toward molecules involved in antigen recognition by autoreactive T cells. Identification of the target autoantigens may lead to specific antigen tolerance. Primary prevention is more speculative and depends on the identification of environmental factors which may initiate beta cell autoimmunity in genetically susceptible individuals. The role of cow's milk proteins has been evocated during retrospective studies. Early interventions in high risk individuals is the only possibility to prevent insulin deficiency.

Autoimmune Diseases↗
PubMed1993

Evidence for a preferential V beta usage by the T cells which adoptively transfer diabetes in NOD mice.

Non-obese diabetic (NOD) mice become spontaneously diabetic as a result of a genetically programmed autoimmune process mediated by autoreactive T lymphocytes and directed against beta cell antigen(s). Studies dealing with T cell receptor (TcR) variable (V) gene usage by such autoreactive T lymphocytes have given contrasted results. Various reasons may explain these discrepancies: the multiplicity of antigenic epitopes putatively recognized by T cells, the ambiguity between specifically committed T cells and passenger lymphocytes homing randomly to the pancreas, the necessarily limited size of the T cell clone panels which have been analyzed for TcR rearrangements and, last but not least, the flexibility of T cell repertoires. To circumvent some of these difficulties, we have decided to concentrate upon the T cell population present in diseased animals and capable of transferring diabetes into young naive NOD recipients. This population, composed of CD4+ and CD8+ T cells, is presumably committed against the relevant beta cell antigens and is the most likely to reveal a bias in V gene usage if such a bias does indeed exist. To find out whether certain V beta genes are more frequently used than others by such pathogenic T cells, T lymphocytes from diabetic donors have been depleted in vitro of defined V beta subsets before being reinoculated into permissive recipients. Out of four V beta families probed under such conditions, three (V beta 8, V beta 5 and V beta 11) are neutral. Their absence neither increases nor reduces the final incidence of successful transfers, indicating that these gene segments are not preferentially used. In contrast, the depletion of V beta 6-positive T cells results in a severe reduction of transfers, suggesting that V beta 6 gene is used with a relatively high frequency by diabetogenic CD4+ and/or CD8+ T cells. To define more precisely which subset uses V beta 6 gene preferentially, we have performed mixing experiments with deleted and intact subsets. The results, based on disease transfer and insulitis severity, indicate that the V beta 6 bias affects predominantly the CD4+ subset. Thus, at variance with several studies concluding that V gene usage in NOD mice is heterogeneous, our present data suggest that disease transferring T cells use a relatively restricted set of V beta genes.

Animals↗
PubMed1993

Autoimmune polyendocrine failure--type 1 (insulin-dependent) diabetes mellitus and hypothyroidism--after allogeneic bone marrow transplantation in a patient with lymphoblastic leukaemia.

In this report we describe a patient who, after allogeneic bone marrow transplantation from her HLA-identical sister, developed polyendocrine failure in the form of Type 1 (insulin-dependent) diabetes mellitus and hypothyroidism. This was the result of the transfer of donor lymphoid cells which were activated by allogeneic bone marrow transplantation. The full chimerism of the recipient was demonstrated by restriction fragment length polymorphism analysis from nucleated blood cells and fibroblast DNA. During the 9-year follow-up, the donor developed hypothyroidism and signs of pre-Type 1 diabetes. This clinical observation resembles the adoptive transfer of diabetes observed in non-obese-diabetic mice and BB rats and confirms the role of immune processes in the pathogenesis of this disease.

Adolescent↗
PubMed1993

Heterogeneity of islet cell cytoplasmic antibodies and autoantibodies to glutamate decarboxylase in relatives of patients with type 1 (insulin-dependent) diabetes.

The aims of our study were to correlate the specificities of islet cell cytoplasmic autoantibodies (ICA) observed in 14 first-degree relatives of diabetic patients with the development of clinical diabetes. To detect whether ICAs recognized in an homogeneous fashion the two major islet cell components, namely beta and alpha cells, the number of islet cells simultaneously recognized by ICAs and anti-glucagon antibodies was determined using a four layer indirect immunofluorescence technique and confocal laser microscopy. The different types of pattern, either whole islet cell staining (type I) or beta cell predominant staining (type II), was then correlated to the presence of autoantibodies to glutamate decarboxylase (GAD), as well as to metabolic outcome. Eight relatives (57.2%) had the type I pattern and 6 (42.8%) the type II pattern. Type 1 diabetes occurred in all ICA positive relatives with the type I pattern and in only 2 out of the 6 relatives with the type II pattern. Interestingly, this later pattern was significantly associated with the presence of autoantibodies to GAD although 2 relatives with antibodies with the type I pattern were also positive. Although more effective for 5 sera with the type II pattern, preincubation with rat brain homogenate significantly decreased the titres of 3/6 sera with the type I pattern. Altogether, our results suggest that autoimmunity to beta cells may be associated with antibodies directed to separate autoantigens with different cellular distributions. From these observations, additional autoantigens distinct from glutamate decarboxylase are also certainly involved.

Adolescent↗
PubMed1992

Human monoclonal islet cell antibodies from a patient with insulin-dependent diabetes mellitus reveal glutamate decarboxylase as the target antigen.

The autoimmune phenomena associated with destruction of the beta cell in pancreatic islets and development of type 1 (insulin-dependent) diabetes mellitus (IDDM) include circulating islet cell antibodies. We have immortalized peripheral blood lymphocytes from prediabetic individuals and patients with newly diagnosed IDDM by Epstein-Barr virus transformation. IgG-positive cells were selected by anti-human IgG-coupled magnetic beads and expanded in cell culture. Supernatants were screened for cytoplasmic islet cell antibodies using the conventional indirect immunofluorescence test on cryostat sections of human pancreas. Six islet cell-specific B-cell lines, originating from a patient with newly diagnosed IDDM, could be stabilized on a monoclonal level. All six monoclonal islet cell antibodies (MICA 1-6) were of the IgG class. None of the MICA reacted with human thyroid, adrenal gland, anterior pituitary, liver, lung, stomach, and intestine tissues but all six reacted with pancreatic islets of different mammalian species and, in addition, with neurons of rat cerebellar cortex. MICA 1-6 were shown to recognize four distinct antigenic epitopes in islets. Islet cell antibody-positive diabetic sera but not normal human sera blocked the binding of the monoclonal antibodies to their target epitopes. Immunoprecipitation of 35S-labeled human islet cell extracts revealed that a protein of identical size to the enzyme glutamate decarboxylase (EC 4.1.1.15) was a target of all MICA. Furthermore, antigen immunotrapped by the MICA from brain homogenates showed glutamate decarboxylase enzyme activity. MICA 1-6 therefore reveal glutamate decarboxylase as the predominant target antigen of cytoplasmic islet cell autoantibodies in a patient with newly diagnosed IDDM.

Adolescent↗
PubMed1992

[Immunologic mechanisms implicated in autoimmune destruction of beta cells in type I diabetes].

Lymphocytic infiltration of the islets of Langerhans results from activation of immunity effector cells during the period preceding clinical onset of diabetes. After escape from thymic selection, the autoreactive cell clones proliferate in the peripheral hemopoietic organs prior to invading the islets of Langerhans. The selection, expansion and activation of autoreactive cells are under genetic control. The development of quantitative tests of cellular immunity should allow determination of the importance of the anti-islet immunologic reaction, suspected at present from the presence of specific autoantibodies in genetically predisposed subjects at high risk of insulin dependence.

Autoimmunity↗
PubMed1991

[Predicting insulin-dependent diabetes. Study of risk markers].

The presence of specific antibodies at the time of clinical diagnosis, together with genetic susceptibility and animal models of spontaneous diabetes obtained by immunological destruction of insulin-secreting cells, suggests that insulin-dependent (type I) diabetes is an autoimmune disease. Prospective studies conducted among first-degree relatives of type I diabetes patients or in the general population have identified 3 types of markers appearing during subclinical destruction of islet cells, or pre-diabetes, which can be used to detect subjects at high risk. These are: high-titer anti-islet antibodies (ICA), anti-insulin autoantibodies and early insulin response to intravenous hyperglycaemia. Owing to the great heterogeneity of metabolic profiles, immunological markers alone cannot predict the time when insulin-dependence will occur. The psychological impact of these studies is such that they should be carried out only in specialized centres. Identifying pre-diabetes is important for the prevention of the disease. Until immunomodulators devoid of side-effects are available, pre-diabetes is a good period to train the patients and start insulin therapy when it becomes necessary.

Autoantibodies↗
PubMed1991

CD8+ T cell homing to the pancreas in the nonobese diabetic mouse is CD4+ T cell-dependent.

The adoptive transfer of type I diabetes in nonobese diabetic mice requires the contribution of both CD4+ and CD8+ T cells. To further elucidate the cellular pathway(s) of beta-cell destruction and the responsibility of each subset, high doses of committed T cells from diabetic mice purified to single subsets, were injected into syngeneic nonobese diabetic neonates. The recipients of single or mixed subsets were followed for clinical manifestations of diabetes and examined at 30 days of age for in situ lesions. None of the animals injected with either CD4+ or CD8+ T cells became overtly diabetic during the 30 days of observation whereas 8 of 23 mice inoculated with a mixture of the two subsets developed glycosuria and hyperglycemia. However, insulitis was found in 6 of the 13 mice injected with CD4+ T cells whereas only 1 of the 9 mice injected with CD8+ T cells showed marginal infiltration of the pancreas. The lesions initiated by CD4+ T cells alone were considerably less severe than those induced by the mixture of both subsets, corroborating the fact that overt disease did not occur in the former group. Together, these results suggest a distinct function for each diabetogenic T cell subset. CD4+ T cells, which have the capacity to home to the pancreas, promote in turn the influx of CD8+ effector T cells that do not by themselves accumulate in this organ. These results illustrate a novel form of T-T cell interactions leading to organ specific autoimmune lesions.

Animals↗
PubMed1991

Autoantibodies and genetic factors associated with the development of type 1 (insulin-dependent) diabetes mellitus in first degree relatives of diabetic patients.

Factors associated with diabetes onset were analysed for their predictive value in 708 first-degree relatives of Type 1 (insulin-dependent) diabetic patients including 374 parents and 308 siblings of Type 1 diabetic patients. Relatives were prospectively followed for 2,304 subject years with blood samples for specific autoantibody evaluation. Islet cell cytoplasmic autoantibody titres were quantified in Juvenile Diabetes Foundation units with a threshold of positivity of 5 units. Insulin autoantibodies were determined using Tyr-A14 iodinated human insulin. HLA typing was performed in 92% of the relatives. During the time of study, 17 of 646 (2.6%) relatives showed islet cell antibodies. During follow-up, eight relatives developed diabetes, including six with high islet cell antibody titre. Taking titres above 20 units increased the positive predictive value from 35% to 75% whereas the presence of insulin autoantibodies did not increase the positive predictive value for the disease. Analysis of metabolic profiles months before the onset of diabetes by either oral or intravenous glucose loads, indicated a considerable level of heterogeneity with relatives with a high islet cell antibody titre who rapidly developed insulin-dependent diabetes, whereas other remained insulin-independent during the same observation period despite comparable titres. This study clearly indicates that initial islet cell antibody titre is not sufficient to predict individual outcome. Follow-up samples are clearly needed to monitor progression of the disease. Few relatives with persistent immunologic positivity progress to clinical Type 1 diabetes, suggesting that non-progressive and sub-clinical Beta-cell dysfunction is common.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Microalbuminuria and diabetic nephropathy. Detection and correlation with other degenerative complications].

The prevalence of microalbuminuria and persistent proteinuria was studied in a population of 801 diabetic patients (535 with type II and 266 with type I diabetes). Urinary albumin excretion rate (AER) was measured on morning samples by laser nephelometry. Normoalbuminuria, as defined, in the absence of contaminated urine, by an albumin: creatinine (A/C) ratio below 2, was found in 551 patients, microalbuminuria (NC greater than or equal to 2 with AER below 200 mg/l) in 190 patients and persistent proteinuria (AER greater than or equal to 200 mg/l) in 60 patients. Microalbuminuria was present in 48 (18 p. 100) IDDM patients and 142 NIDDM patients. In IDDM patients, AER increased with the duration of the disease with no apparent influence of age at the onset. The prevalence of hypertension was 25 p. 100 and 61 p. 100 in IDDM patients with microalbuminuria and macroproteinuria respectively versus 10 p. 100 in patients with normoalbuminuria. This prevalence increased in NIDDM patients from 39.3 p. 100 with normoalbuminuria to 40.8 p. 100 and 76.2 p. 100 with microalbuminuria or macroproteinuria respectively. Proliferative retinopathy in type I and type II patients with normal AER was 7.4 p. 100 and 1.2 p. 100 respectively increasing to 15.2 p. 100 and 8.9 p. 100 with microalbuminuria and 27.8 p. 100 and 23.1 p. 100 with macroproteinuria. The prevalence of coronary disease increased from 4 to 10.4 p. 100 in patients with type I diabetes and microalbuminuria. The prevalence of cardiac failure increased from 1.5 to 2.1 p. 100 in type I diabetics and from 3.2 to 7.8 p. 100 in type II diabetics in the presence of microalbuminuria. Patients with microalbuminuria had increased levels of glycosylated hemoglobin A 1C but statistical difference was only obtained for patients with type II diabetes. Routine analysis of AER in diabetics allows early detection of diabetic nephropathy and emphasizes the need for tight metabolic and blood pressure control. Hypertension can be detrimental to nephropathy but might also initiate renal lesions in NIDDM patients.

Adult↗
PubMed1990

Measuring vibration sensations with graduated tuning fork. Simple and reliable means to detect diabetic patients at risk of neuropathic foot ulceration.

To find a simple and reliable means to measure vibration sensations, 189 diabetic patients and 88 control subjects were tested at different sites with a graduated tuning fork. Within-test variation at big toes reached 8.4% in diabetic patients vs. 2.2% in control subjects. Mean contralateral variation was 7.5% in diabetic patients vs. 2.5% in control subjects. Tuning-fork sensations were inversely correlated with duration of diabetes, whereas no correlation was found with HBA1c levels or the severity of retinopathy. Ninety-nine (52%) patients had vibratory sensation at big toes of less than 99th percentile of normal values for age. In addition, 51% of the patients with clinical symptoms at extremities (n = 67), 70% of the patients without tendon reflexes (n = 50), and 75% of the patients with abnormal nerve conduction velocities (n = 60) also had low vibration sensations. All patients with lower-limb injuries (n = 7) had values at big toes of less than 2. Altogether, the graduated tuning fork represents a simple and reliable alternative to quantitate vibration sensations. Long-term follow-up of asymptomatic patients will indicate whether these abnormalities reflect underlying neuropathy. Patients with abnormal values at screening will necessitate additional investigations and special foot-care education programs.

Adolescent↗
PubMed1990

[Pseudomyasthenic pre-Basedow ophthalmoplegia].

A 67-year old woman presented with isolated and bilateral external ophthalmoplegia of the myasthenic type following a subacute course and resistant to anticholesterinases and corticosteroids. A biological hyperthyroidism with immunological markers was discovered. An intensive care of corticosteroids was partially effective, but fatal bone marrow aplasia attributed to carbimazole developed. Pure ophthalmoplegia without local signs of inflammation may be the sole manifestation of dysthyroid orbitopathy.

Aged↗