Interleukin-10 is a predominant cytokine in atopic dermatitis.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to E F Lampeter.
Explore the source record for details and available documents.
We studied the effect of severe reduction of beta-cell mass by 90% pancreatectomy on the immune tolerance to the endocrine pancreas. Four months after subtotal pancreatectomy all LEW.Han rats had developed mononuclear infiltration of islets and 9 of 14 rats were positive for islet-cell antibodies. Electron microscopy revealed lymphocytic invasion of endocrine tissue, lysis of beta cells and phagocytotic macrophages. None of these changes were seen 2 weeks after 90% pancreatectomy or 4 months after 10% pancreatectomy. Weekly substitution of islet antigens in the form of a homogenate of 100 islets into 90% pancreatectomized LEW.Han rats almost completely prevented the development of insulitis and autoantibodies. The dependence of insulitis on T cells was shown when 90% pancreatectomy in LEW.rnu rats (i.e., the congenic athymic nude strain), did not result in islet infiltration. The exocrine tissue remained normal in all experimental groups. During the observation period insulitis was not associated with overt diabetes but was accompanied by substantial enlargement of islets and of beta-cell mass, as shown by morphometry. Suppression of islet inflammation by injection of islet antigens abolished beta-cell regeneration, despite continuing metabolic stress in rats with 90% pancreatectomy. The findings indicate induction of islet autoimmunity in response to 90% but not to 10% pancreatectomy. We conclude that severe reduction of the islet-antigen mass allows the development of T-cell-dependent islet autoimmunity which indicates a loss of immune tolerance. In addition, the data suggest the existence of islet-antigen autoreactive immune cells in rats not genetically predisposed to autoimmune diabetes. Finally, we conclude that selective beta-cell regeneration occurs in association with insulitis.
Islet cell antigen (ICA) 69 is a newly-recognized islet cell antigen to which autoantibodies have been observed in prediabetic relatives of patients with insulin-dependent-diabetes mellitus (IDDM). Here we extend the earlier analysis of ICA69 antibodies to patients with recent-onset IDDM and to patients with other immune-mediated diseases. ICA69 antibodies were determined by Western blot using an affinity purified recombinant fusion protein of ICA69 and maltose binding protein. ICA69 antibody quantities were determined as titres using a titration curve of a standard serum as reference. Mean logarithmic ICA69 antibody titres were 3.4 (+/- 1.4) in 99 patients with acute IDDM compared to 2.8 (+/- 0.9) in 49 healthy blood donors (p < 0.001). A higher mean ICA69 antibody titre of 4.1 (+/- 0.8) was observed in 16 patients with rheumatoid arthritis in comparison to acute IDDM (p < 0.01) and healthy control subjects (p < 0.001). The percentage of sera with ICA69 antibody titres above the 2 SD level of normal subjects was 21% in IDDM, 31% in rheumatoid arthritis and 6% in healthy blood donors. None of the patients with autoimmune thyroid disease (n = 20), inflammatory bowel disease (n = 9) or multiple sclerosis (n = 7) had elevated ICA69 antibodies. In IDDM, presence of ICA69 antibodies persisted and the titre remained the same over 18 months of follow-up. The relationship of ICA69 antibodies to islet cell antibodies (ICA) or insulin autoantibodies (IAA) was tested. The production of ICA69 antibodies was not associated in diabetic patients with the presence of any of the two other autoantibodies.(ABSTRACT TRUNCATED AT 250 WORDS)
Subtotal pancreatectomy (90%) in Lewis rats induces chronic islet inflammation and tissue damage in the remaining pancreas 4 months after surgery. Concomitantly, significant enlargement of the islets of Langerhans was observed (90% pancreatectomy: islet/pancreas area: 25.6 +/- 9.6 x 10(-3), beta-cell/pancreas area: 12.4 +/- 4.4 x 10(-3); n = 4; controls without pancreatectomy: islet/pancreas area: 5.5 +/- 1.7 x 10(-3), beta-cell/pancreas area: 4.6 +/- 1.5 x 10(-3); n = 4; p < 0.05, respectively). Islet growth is mainly due to an increase in beta-cell mass. Beta-cell regeneration was not caused by the surgical manipulations or by metabolic stress. The former was ruled out by performing 10% pancreatectomy which did not cause islet enlargement after 4 months (islet/pancreas area: 13.6 +/- 11.3 x 10(-3), beta-cell/pancreas area: 7.1 +/- 2.0 x 10(-3); n = 3). An influence of metabolic stress was excluded by continuous substitution of syngenic islet antigens, which inhibits insulitis. In the absence of islet inflammation, despite persistent metabolic stress, beta-cell regeneration did not occur (islet/pancreas area: 7.0 +/- 5.5 x 10(-3), beta-cell/pancreas area: 5.5 +/- 4.1 x 10(-3); n = 4). Continuous treatment of animals after 90% pancreatectomy by insulin implants (1.5 U/day) avoided insulitis and beta-cell growth (islet/pancreas area: 9.2 +/- 1.1 x 10(-3), beta-cell/pancreas area: 6.8 +/- 1.0 x 10(-3), n = 3): All enlarged islets observed 4 months after 90% pancreatectomy without further treatment were infiltrated. Thus, beta-cell growth appears to be a response to insulitis. The stimulus for beta-cell growth could result from tissue damage caused by infiltrating cells or from cytokines secreted by the infiltrating cells, or both.
The hypothesis was tested that islet autoimmunity is induced by ongoing islet cell destruction in subjects with susceptibility genes HLA-DR 3 and/or DR 4. Sixty-one patients with confirmed chronic pancreatitis were analysed, 30 of whom expressed HLA-DR 3 and/or DR 4. Electron microscopy studies in 10 patients showed that the inflammatory process also affected islets, as recognisable from islet cell lysis, intrainsular fibrosis and immune cell infiltrates. None of the sera tested contained any of three markers of islet autoimmunity, ICA, IAA or GAD antibodies. A correlation was seen between the loss of exocrine function, as determined by the ALTAB-test, and of beta-cell function, as determined by the C-peptide response to i.v. glucagon. However, there was no preferential loss of beta-cell function in patients with HLA-DR 3 and/or DR 4. We conclude that islet cell destruction occurs during chronic pancreatitis, but does not trigger islet autoimmunity, even in the presence of HLA-DR 3 and/or DR 4.
Explore the source record for details and available documents.
OBJECTIVE: To investigate the effect of an antiedematous therapy with the histamine antagonist ketotifen on beta-cell function in late prediabetes. RESEARCH DESIGN AND METHODS: In a randomized double-blind placebo-controlled study, ketotifen was administered for 3 months to 9 islet cell antibody positive (ICA+) prediabetic patients with a first-phase insulin response (FPIR) below the 2.5th percentile to preserve residual beta-cell function. Patients were followed by intravenous glucose tolerance tests (IVGTTs) every 4-6 weeks for determination of FPIR, HbA1, ICAs, and insulin autoantibodies. In 5 patients, the immune activation state was followed by determination of serum levels of tumor necrosis factor-alpha (TNF-alpha), beta 2-microglobulin, and C-reactive protein (CRP). RESULTS: Seven of nine patients developed diabetes within one year of follow-up. Irrespective of treatment with ketotifen, a slow and linear decline (P < 0.05) of 1 + 3-min insulin values was observed in sequential IVGTTs in those 7 patients who developed insulin-dependent diabetes mellitus (IDDM) during follow-up. The 2 other patients showed wide fluctuations of the insulin response with a threefold increase of initial insulin levels. HbA1 did not correlate with FPIR. Fasting blood glucose increased significantly during the study (P < 0.05). Individual levels of serum TNF-alpha, CRP, and beta 2-microglobulin did not change during the study. CONCLUSIONS: The study could not demonstrate preservation of beta-cell function by ketotifen in the late stage before manifestation of clinical diabetes. Manifestation is preceded in the last 6 months by a steady loss of the FPIR without rapid deterioration immediately before diagnosis and without signs of increased immune activity.
Insulin-dependent diabetes was observed in a woman, aged 29, 4 years after transplantation of bone marrow from her HLA-identical brother with insulin-dependent diabetes. Both had classic symptoms and insulin dependency from onset. At diagnosis of diabetes the recipient was positive for high-titre islet cell antibodies (ICA) whereas she had been ICA negative before transplantation. Chromosomal analyses verified that all circulating leucocytes were of male donor type. These findings suggest transfer of insulin-dependent diabetes by bone marrow cells and confirm the immune nature of the disease.
Explore the source record for details and available documents.
UNLABELLED: Nicotinamide is a prime candidate for clinical trials on preventing Type 1 diabetes. It is thought to protect Beta-cells mainly by increasing intracellular NADP levels via competitive inhibition of poly-(ADP-ribose)-polymerase. Thus, since nicotinamide protects target cells while under autoimmune attack it should be used at a time when sufficient numbers of beta-cells are still present, i.e. in the early stages of diabetes development. Increased diabetes risk can be identified by the presence of islet cell antibodies (ICA) and an increasing number of other more or less well defined antibodies in relatives of Type 1 diabetic patients. However, ICA is the best-evaluated marker and was therefore chosen for initial screening. The aim of the German Nicotinamide Intervention Study (DENIS) is to evaluate the potency of nicotinamide at protecting children with an increased risk of Type 1 diabetes from manifestation of the disease. The trial is placebo-controlled and double-blinded. A sustained-release preparation of nicotinamide is given at a dose of 1.2 g/m2 body surface. Entry criteria: ICA > or = 20 JDF units (at least two positive readings within 6 months, > or = 3 months apart, one measurement > or = 20 JDF units); siblings of Type 1 diabetic patients, 3-12 years of age; IVGTT performed. EXCLUSION CRITERIA: diabetes according to WHO criteria (including abnormal OGTT); no written consent; other chronic diseases. Definition of endpoint: Diabetes according to WHO criteria.(ABSTRACT TRUNCATED AT 250 WORDS)
In this study, subsets of mononuclear infiltrates in pancreatic islets of BB rats at different stages of insulitis were determined by various monoclonal antibodies against rat lymphoid cells, including a mouse monoclonal IgM antibody that distinguishes between macrophages and dendritic cells (mAb 1F119). 1F119+ dendritic cells were absent in and around islets of Wistar control rats. In BB rats, the first alteration of islets detectable by immunohistochemistry when compared with normal islets was the enhanced expression of 1F119 antigen around and in the islets (17% 1F119+ islets). At disease stage 1 (i.e. no leukocyte infiltration after HE staining), lymphocytes and macrophages were almost absent. At disease stage 2 (leukocyte infiltration < 20 cells), a more intense form of dendritic cell infiltration was seen (stage 1 versus stage 2, P < 0.0001). In addition, ED2+ and ED3+ cells were present around the islets (50% of islets were infiltrated with 1F119+ cells versus 16% with ED2+, 19% with ED3+, 11% with W3/25+ cells, and 11% with OX8+ cells, P < 0.0001). At disease stage 3 (> 20 cells), a clear increase of ED2+ and ED3+ macrophages and of W3/25+ and OX8+ T-lymphocytes in the infiltrates was observed. These observations suggest a role for antigen presenting dendritic cells in the initiation of immune reaction in type 1 diabetes of BB rats.
Ciamexon (CMX), a new immunomodulatory compound acting mainly on B-lymphocytes was given orally to 42 NOD mice divided into three sex and litter matched groups (A: 0.3 mg/mouse/day CMX, B: 1.5 mg/mouse/day CMX, C: control) from 7 weeks of age. Animals were followed up for evaluation of diabetes incidence up to 32 weeks of age. There was a tendency for a delayed onset of hyperglycemia in mice of group B up to 26 weeks of age; however no significant difference in the cumulative incidence of diabetes at 32 weeks of age was observed (A: 57.5%, B: 38.5%, C: 38.5%). No differences were found in the number of infiltrated islets in animals culled at 10 weeks of age treated with CMX from 4 weeks of age. We conclude that CMX does not modify the course of insulitis and diabetes incidence in NOD mice although though the appearance of glycosuria was delayed by this treatment.
An association between the incidence of childhood Type 1 (insulin-dependent) diabetes mellitus and the average yearly temperature in different countries has been reported, the incidence being higher in countries with a lower mean temperature. We have studied the effect of environmental temperature on the incidence of diabetes in an animal model of Type 1 diabetes, the non-obese diabetic (NOD) mouse. Female NOD mice were divided at weaning, with one group placed at a higher temperature (mean 23.7 +/- 1.7 degrees C) and the other at a lower temperature (21.0 +/- 1.8 degrees C). At 20 weeks of age 6 of 16 mice at lower temperature and 1 of 17 mice at higher temperature had developed diabetes (p less than 0.02); at 30 weeks 10 of 16 and 5 of 17 mice had developed diabetes (p less than 0.05). Non-diabetic animals in the low temperature group had a higher food intake than those in the high temperature group between 13-15 weeks of age (28.0 +/- 1.2 g/week vs 24.8 +/- 0.7 g/week, p less than 0.05). In a parallel experiment, histological examination showed that there were similar degrees of insulitis in the high and low temperature groups at seven weeks of age. We conclude that environmental temperature can affect the incidence of diabetes in the NOD mouse and that this may be related to alterations in food intake.
Suitable animal models of human Type 1 (insulin-dependent) diabetes mellitus have long been sought, in particular a model that would permit detailed histological and immunological investigation of changes in the islet preceding the metabolic disorder. This would allow hypotheses as to pathogenesis of the condition to be examined and interventions such as immunotherapy to be tested. The most widely studied models include the low-dose streptozotocin induced diabetic mouse and the BB rat, but both differ in important respects from the human disease. In this review we describe one highly successful model, the non obese diabetic mouse. Selected aspects of pathogenesis and immunotherapy are presented and analogies with human Type 1 diabetes discussed.
In 20 patients with a newly diagnosed type I diabetes mellitus a cytotoxic effect of blood lymphocytes against beta cells of the pancreas of neonatal rats could be demonstrated. This effect remained nearly unchanged during the first 12 months of control. During the course up to 18 months, the cytotoxicity decreased significantly. After stimulation with glucose and glucagon, a C-peptide secretion was demonstrated in all patients during the first 12 months but it decreased thereafter. The follow-up study showed cell-mediated immune reactions against beta cells in type I diabetics as long as the existence of beta cells can be assumed on the basis of functional tests. Thus the immune process seems to depend on the presence of the specific antigen.
The ultrastructure of peripheral blood lymphocyte subsets and activated lymphocytes from 5 patients with recent onset insulin-dependent diabetes as identified by monoclonal antibodies (CD4, CD8 and 4F2) and labelled with gold coupled goat anti-mouse IgG are described and depicted. Electron microscopy revealed no differences in appearance between investigated lymphocyte subsets at the single cell level. Activated lymphocytes as defined by an early activation antigen (4F2) do not always have a characteristic appearance nor do they show morphological signs of activation in all cases. We would conclude that it is not possible to recognize different lymphocyte subsets based only on their ultrastructure.
A cytotoxic effect of peripheral blood mononuclear cells from 22 out of 23 newly diagnosed Type 1 (insulin-dependent) diabetic patients against B cells of isolated rat islets was demonstrated. The addition of peripheral blood mononuclear cells from healthy subjects reduced the cytotoxic effect in 9 out of 10 patients. The addition of peripheral blood mononuclear cells from other diabetic patients was without significant effect in 14 out of 16 cases. The results indicate functional abnormalities of peripheral blood mononuclear cells in newly diagnosed Type 1 diabetes. Beside cytotoxic effects against B cells, a defect in the suppressor function seems to exist. The activation of T-lymphocytes might be a consequence of such a defect.
The first morphological and biochemical findings on the effect of leukocytes from a newly diagnosed type I diabetic patient on isolated rat islets are presented. Leukocytes from venous blood were co-incubated with isolated neonatal rat islets for 22 h. According to the biochemical and electron-microscopical findings, beta cells localized in the periphery of the islets and a few single beta cells show lytic alterations (single cell necroses). The electron micrographs suggest that the beta cells were lysed after contact with lymphocytes or lymphoid cells from the diabetic patient (target cell reaction). The simultaneous biochemical and morphological investigations reveal that after beta cell lysis, insulin released in a granular state can be phagocytosed by granulocytes and thus escape the estimation of insulin concentration in the medium.