Safety and efficacy of metformin for therapy-induced hyperglycemia in children with acute lymphoblastic leukemia.

BACKGROUND: Hyperglycemia during corticosteroid and asparaginase therapy for acute lymphoblastic leukemia is a significant side effect that is usually treated with insulin. Metformin is an oral antidiabetic biguanide that may cause metabolic acidosis and liver enzyme abnormalities of possible concern in patients receiving chemotherapy. PROCEDURE: We reviewed patients with acute lymphoblastic leukemia treated with corticosteroids and asparaginase who received metformin for control of hyperglycemia. RESULTS: Seventeen patients received metformin, including 4 who received insulin before starting metformin therapy. Twelve were treated during initial induction therapy and 5 during relapse reinduction. Corticosteroids included dexamethasone in 11, prednisone in 5, and megesterol in 1. Fifteen received pegasparaginase.Patients were treated with metformin for a median of 6 days (range, 2 to 46 d). Metformin was started at a median glucose level of 286 mg/dL (range, 112 to 499 mg/mL). The glucose level was controlled with metformin alone in 12 patients without the need for insulin. Four patients received insulin before or concomitantly with metformin. In 1 patient, metformin failed to control the glucose level, and insulin was administered.No significant toxicity from metformin was seen. Two patients had an elevated anion gap and creatinine level because of extreme hyperglycemia. One patient had mild elevation in total bilirubin and 5 patients had mild elevation in serum alanine aminotransferase levels. There were no episodes of hypoglycemia. CONCLUSIONS: Metformin is safe and effective for therapy-induced hyperglycemia. Initially, insulin may be required for significant hyperglycemia or metabolic abnormalities. We are unaware of any prior studies using metformin in this population.

A peptide-major histocompatibility complex II chimera favors survival of pancreatic beta-islets grafted in type 1 diabetic mice.

BACKGROUND: Transplantation of pancreatic islets showed a tremendous progress over the years as a promising, new therapeutic strategy in patients with type 1 diabetes. However, additional immunosuppressive drug therapy is required to prevent rejection of engrafted islets. The current immunosuppressive therapies showed limited success in maintaining long-term islet survival as required to achieve insulin independence in type 1 diabetes, and they induce severe adverse effects. Herein, we analyzed the effects of a soluble peptide-major histocompatibility complex (MHC) class II chimera aimed at devising an antigen-specific therapy for suppression of anti-islet T cell responses and to improve the survival of pancreatic islets transplants. METHODS: Pancreatic islets from transgenic mice expressing the hemagglutinin antigen in the beta islets under the rat insulin promoter (RIP-HA) were grafted under the kidney capsule of diabetic, double transgenic mice expressing hemagglutinin in the pancreas and T cells specific for hemagglutinin (RIP-HA, TCR-HA). The recipient double transgenic mice were treated or not with the soluble peptide-MHC II chimera, and the progression of diabetes, graft survival, and T cell responses to the grafted islets were analyzed. RESULTS: The peptide-MHC II chimera protected syngeneic pancreatic islet transplants against the islet-reactive CD4 T cells, and prolonged the survival of transplanted islets. Protection of transplanted islets occurred by polarization of antigen-specific memory CD4 T cells toward a Th2 anti-inflammatory response. CONCLUSIONS: The peptide-MHC II chimera approach is an efficient and specific therapeutic approach to suppress anti-islet T cell responses and provides a long survival of pancreatic grafted islets.

Fetal or neonatal low-glycotoxin environment prevents autoimmune diabetes in NOD mice.

Advanced glycation end products (AGEs) are implicated in beta-cell oxidant stress. Diet-derived AGE (dAGE) are shown to contribute to end-organ toxicity attributed to diabetes. To assess the role of dAGE on type 1 diabetes, NOD mice were exposed to a high-AGE diet (H-AGE) and to a nutritionally similar diet with approximate fivefold-lower levels of N(epsilon)-carboxymethyllysine (CML) and methylglyoxal-derivatives (MG) (L-AGE). Suppression of serum CML and MG in L-AGE-fed mice was marked by suppression of diabetes (H-AGE mice >94% vs. L-AGE mice 33% in founder [F](0), 14% in F(1), and 13% in F(2) offspring, P < 0.006) and by a delay in disease onset (4-month lag). Survival for L-AGE mice was 76 vs. 0% after 44 weeks of H-AGE mice. Reduced insulitis in L-AGE versus H-AGE mice (P < 0.01) was marked by GAD- and insulin-unresponsive pancreatic interleukin (IL)-4-positive CD4+ cells compared with the GAD- and insulin-responsive interferon (IFN)-gamma-positive T-cells from H-AGE mice (P < 0.005). Splenocytes from L-AGE mice consisted of GAD- and insulin-responsive IL-10-positive CD4+ cells compared with the IFN-gamma-positive T-cells from H-AGE mice (P < 0.005). Therefore, high AGE intake may provide excess antigenic stimulus for T-cell-mediated diabetes or direct beta-cell injury in NOD mice; both processes are ameliorated by maternal or neonatal exposure to L-AGE nutrition.

Proficiency testing in immunopathology: establishing the homogeneity of test material.

AIMS: To develop a technique for homogeneity testing of serum aliquot samples suitable for use in the Quality Assurance Program in Clinical Immunology (QAP Pty Ltd). METHODS: Albumin was selected as the surrogate protein marker for the product to be tested and the coefficient of dispersion (COD) calculated as the measure of homogeneity. To detect changes in the average level of homogeneity, cumulative sum control (cusum) charts were used. RESULTS: The COD(%) for each triplicate reading of albumin obtained from 34 specimens was normally distributed with a mean of 0.49% and a standard deviation of 0.25%. In industrial quality control schemes the action line is generally set at the upper 99% confidence limits, hence any triplicate sample would be considered to have acceptable homogeneity if the COD was < or = 1.08%. Cusum charts were created to monitor albumin homogeneity over time. CONCLUSIONS: The use of albumin measurement as the surrogate appears statistically suitable for homogeneity testing in QAP programs for immunodiagnostic testing. CUSUM charts are particularly useful to monitor such homogeneity testing.

Adenovirus-mediated expression of glucokinase in the liver as an adjuvant treatment for type 1 diabetes.

Glucokinase (GK) plays a crucial role in hepatic glucose disposal. Its activity is decreased in patients with maturity-onset diabetes of the young and in some animal models of diabetes. We investigated the feasibility of manipulating GK expression as an adjuvant treatment for type 1 diabetes, using an E1/E3-deleted adenoviral vector (Ad.EF1(alpha)GK) delivered to the liver of streptozotocin-induced type 1 diabetic rats. First, we studied the metabolic impact of constitutive glucokinase expression in the absence of insulin. Normal blood glucose levels were observed after gene transfer, and glucose tolerance was substantially enhanced compared with diabetic control animals, suggesting that hepatic GK expression is a feasible mechanism to enhance glucose disposal. In a second study we administered Ad.EF1(alpha)GK together with subcutaneous insulin injections to determine whether the combined action of insulin plus GK activity would provide better glucose homeostasis than insulin treatment alone. This combination approach resulted in constant, near-normal glucose values under fed conditions. Furthermore, the animals stayed in the normoglycemic range after an overnight fast, indicating that the risk to develop hypoglycemia is not increased by expression of GK. Alterations of other metabolic routes were observed, suggesting that insulin-regulated expression of GK may be necessary to use the strategy as a treatment of type 1 diabetes.

Ambulatory REACT: real-time seizure detection with a DSP microprocessor.

REACT (Real-Time EEG Analysis for event deteCTion) is a Support Vector Machine based technology which, in recent years, has been successfully applied to the problem of automated seizure detection in both adults and neonates. This paper describes the implementation of REACT on a commercial DSP microprocessor; the Analog Devices Blackfin®. The primary aim of this work is to develop a prototype system for use in ambulatory or in-ward automated EEG analysis. Furthermore, the complexity of the various stages of the REACT algorithm on the Blackfin processor is analysed; in particular the EEG feature extraction stages. This hardware profile is used to select a reduced, platform-aware feature set, in order to evaluate the seizure classification accuracy of a lower-complexity, lower-power REACT system.

EEG compression using JPEG2000: how much loss is too much?

Compression of biosignals is an important means of conserving power in wireless body area networks and ambulatory monitoring systems. In contrast to lossless compression techniques, lossy compression algorithms can achieve higher compression ratios and hence, higher power savings, at the expense of some degradation of the reconstructed signal. In this paper, a variant of the lossy JPEG2000 algorithm is applied to Electroencephalogram (EEG) data from the Freiburg epilepsy database. By varying compression parameters, a range of reconstructions of varying signal fidelity is produced. Although lossy compression has been applied to EEG data in previous studies, it is unclear what level of signal degradation, if any, would be acceptable to a clinician before diagnostically significant information is lost. In this paper, the reconstructed EEG signals are applied to REACT, a state-of-the-art seizure detection algorithm, in order to determine the effect of lossy compression on its seizure detection ability. By using REACT in place of a clinician, many hundreds of hours of reconstructed EEG data are efficiently analysed, thereby allowing an analysis of the amount of EEG signal distortion that can be tolerated. The corresponding compression ratios that can be achieved are also presented.

Effect of ingested interferon-alpha on beta-cell function in children with new-onset type 1 diabetes.

OBJECTIVE: To evaluate the safety and efficacy of ingested human recombinant interferon-alpha (hrIFN-alpha) for preservation of beta-cell function in young patients with recent-onset type 1 diabetes. RESEARCH DESIGN AND METHODS: Subjects aged 3-25 years in whom type 1 diabetes was diagnosed within 6 weeks of enrollment were randomly assigned to receive ingested hrIFN-alpha at 5,000 or 30,000 units or placebo once daily for 1 year. The primary outcome was change in C-peptide secretion after a mixed meal. RESULTS: Individuals in the placebo group (n = 30) lost 56 +/- 29% of their C-peptide secretion from 0 to 12 months, expressed as area under the curve (AUC) in response to a mixed meal. In contrast, children treated with hrIFN-alpha lost 29 +/- 54 and 48 +/- 35% (for 5,000 [n = 27] and 30,000 units [n = 31], respectively, P = 0.028, ANOVA adjusted for age, baseline C-peptide AUC, and study site). Bonferroni post hoc analyses for placebo versus 5,000 units and placebo versus 30,000 units demonstrated that the overall trend was determined by the 5,000-unit treatment group. Adverse events occurred at similar rates in all treatment groups. CONCLUSIONS: Ingested hrIFN-alpha was safe at the doses used. Patients in the 5,000-unit hrIFN-alpha treatment group maintained more beta-cell function 1 year after study enrollment than individuals in the placebo group, whereas this effect was not observed in patients who received 30,000 units hrIFN-alpha. Further studies of low-dose ingested hrIFN-alpha in new-onset type 1 diabetes are needed to confirm this effect.

A multilaboratory peer assessment quality assurance program-based evaluation of anticardiolipin antibody, and beta2-glycoprotein I antibody testing.

We evaluated the performance of anticardiolipin (aCL) and beta2-glycoprotein I (beta2-GPI) antibody assays through a large external quality assurance program. Data from the 2002 cycle of the Royal College of Pathologists of Australasia Quality Assurance Program (RCPA QAP) were analyzed for variation in reported numerical values and semiquantitative results or interpretations according to method type or group and in conjunction with available clinical data. High interlaboratory variation in numerical results and notable method-based variation, combined with a general lack of consensus in semiquantitative reporting, continues to be observed. Numerical results from cross-laboratory testing of 12 serum samples (for immunoglobulin G [IgG]-aCL, IgM-aCL, and IgG-beta2-GPI) yielded interlaboratory coefficients of variation (CVs) that were higher than 50% in six of 12 (50%) specimens for IgG-aCL, and 12 of 12 (100%) specimens for IgM-aCL and IgG-beta2-GPI. Semiquantitative reporting also varied considerably, with total (100%) consensus occurring in only four of 36 (11%) occasions. General consensus (where > 90% of participating laboratories agreed that a given serum sample gave a result of either negative or positive) was only obtained on 13 of 36 (36%) occasions. Variation in results between different method types or groups were also present, resulting in potential biasing of the RCPA QAP-defined target results by the large number of laboratories using the dominant aCL assays. Finally, laboratory findings frequently did not agree with the available clinical information. In conclusion, in a large proportion of specimens from the 2002 RCPA QAP cycle, laboratories could not agree on whether a serum sample tested was aCL-positive or aCL-negative, or beta2-GPI-positive or beta2-GPI-negative. Despite prior attempts to improve the standardization of testing and reporting practices, laboratory testing for aCL and anti-beta2-GPI still demonstrates significant interlaboratory and intermethod variation, which needs to be taken into account for the clinical interpretation of test results, especially those from different laboratories.

Soluble, dimeric HLA DR4-peptide chimeras: an approach for detection and immunoregulation of human type-1 diabetes.

Still there are no effective methods to predict or cure type 1 diabetes (T1D) in humans. Soluble, dimeric MHC class II-peptide (DEF) chimeras have potential for both early diagnosis and immunospecific therapy. DEF chimeras prevent and reverse diabetes in mice by stimulating antigen-specific type 1 T regulatory cell (Tr1)-like cells. We also showed that diabetes could be predicted by changes in the phenotype of autoreactive CD4 T cells in peripheral blood. Herein, we demonstrated that human DEF (HLA-DR*0401/Fcgamma1) chimeras expressing peptides of beta-cell antigens stimulate Tr1-like cells in blood of patients with T1D, non-diabetic relatives, and controls. Furthermore, the specific and stable binding of DEF chimeras to cognate TCR and CD4 coreceptor allowed quantification and phenotyping of autoreactive CD4 T cells in non-stimulated blood by FACS. Our results indicate that (1) autoreactive CD4 T cells to GAD65 autoantigen are commonly present in humans expressing diabetes-susceptible HLA-DR*0401 molecules; (2) these autoreactive T cells undergo avidity maturation upon encountering the self antigen early in life; (3) the disease is associated with an imbalance between autoreactive CD4+CD25+ and CD4+CD69+ T cells specific for GAD65. Based on this, we propose a model to explain the kinetics of autoreactive CD4 T cells in blood during the natural history of T1D.

Immunokinetics of autoreactive CD4 T cells in blood: a reporter for the "hit-and-run" autoimmune attack on pancreas and diabetes progression.

Little is known about the fate of autoreactive CD4 T cells in blood. Using a mouse model for spontaneous autoimmune diabetes we demonstrated that the status of the autoimmune process in pancreas could be pictured through the frequency and phenotype of autoreactive CD4 T cells in the blood. Early during the prediabetic stage, the frequency of these cells in blood decreased as a consequence of their recruitment in the pancreas. This was followed by an imbalance between CD4(+)CD25(+) and CD4(+)CD69(+) T cells in the pancreas that was mirrored in the phenotype of autoreactive T cells in the blood. Waves of activated CD4(+)CD69(+) T cells in blood preceded the disease onset suggesting that the autoimmune attack on pancreas is a discontinuous "hit-and-run" rather than a continuous process. Tracking autoreactive CD4 T cells in blood may help in identifying prediabetic humans and monitoring the disease progression during therapeutic interventions.

Down-regulation of diabetogenic CD4+ T cells by a soluble dimeric peptide-MHC class II chimera.

Type 1 diabetes is an organ-specific autoimmune disease that is mediated by autoreactive T cells. We show here that administration of a soluble dimeric peptide-major histocompatibility complex (pMHC) class II chimera (DEF) to prediabetic double-transgenic mice prevents the onset of disease or, in animals that are already diabetic, restores normoglycemia. The antidiabetogenic effects of DEF rely on the induction of anergy in splenic autoreactive CD4+ T cells via alteration of early T cell receptor signaling and stimulation of interleukin 10-secreting T regulatory type 1 cells in the pancreas. Soluble dimeric pMHC class II may be useful in the development of immunospecific therapies for type 1 diabetes.