Low-density lipoprotein cholesterol in adolescents and young adults with type 1 diabetes: Data from the Australasian Diabetes Data Network registry.

AIM: To determine low-density lipoprotein cholesterol (LDL-C) screening frequency and levels, and factors associated with elevated LDL-C, in Australasian youth with type 1 diabetes (T1D). METHODS: Data were extracted from the Australasian Diabetes Data Network (ADDN), a prospective clinical quality registry, on all T1D healthcare visits attended by young people aged 16-25 years (with T1D duration of >1 year) between January 2011 and December 2020. The primary outcomes were elevated LDL-C > 2.6 mmol/L (100 mg/dL) and threshold for treatment: >3.4 mmol/L (130 mg/dL), according to consensus guidelines. Multivariable Generalised Estimated Equations (GEE) were used to examine factors associated with elevated LDL-C across all visits. RESULTS: A cohort of 6338 young people (52.6% men) were identified, of whom 1603 (25.3%) had ≥1 LDL-C measurement documented. At last measurement, mean age, age at T1D diagnosis and T1D duration were 18.3 ± 2.4, 8.8 ± 4.5 and 8.9 ± 4.8 years, respectively. LDL-C was elevated in 737 (46.0%) and at the treatment threshold in 250 (15.6%). In multivariable GEE elevated LDL-C continuously was associated with older age (OR = 0.07; 0.01-0.13, p = 0.02), female sex (OR = 0.31; 0.18-0.43; p < 0.001), higher HbA1c (OR = 0.04; 0.01-0.08; p = 0.01) and having an elevated BMI (OR = 0.17, 0.06-0.39, p < 0.001). CONCLUSIONS: LDL-C screening and levels are suboptimal in this cohort, increasing future cardiovascular complication risk. There is an urgent need to understand how healthcare services can support improved screening and management of dyslipidaemia in this population.

Glucose alert system improves health professional responses to adverse glycaemia and reduces the number of hyperglycaemic episodes in non-critical care inpatients.

AIM: To investigate the effect of a novel glucose alert system, comprising the Melbourne Glucose Alert Pathway and glucose-alert-capable networked blood glucose meters, on nursing and hospital medical officer responses to adverse glycaemia. METHODS: A prospective, pre- and post-observational study was undertaken in non-critical care wards of a tertiary hospital over 4 months (n=148 or 660 patient-days). The intervention consisted of two components designed to promote a consistent staff response to blood glucose measurements: (1) a clinical escalation pathway, the Melbourne Glucose Alert Pathway, and (2) networked blood glucose meters, which provide a visual alert for out-of-range blood glucose measurement. All consecutive inpatients with diabetes were assessed for diabetes management and capillary blood glucose. The primary outcome was documented nursing and medical staff action in response to episodes of adverse glycaemia (blood glucose >15 mmol/l or <4 mmol/l). Secondary outcomes consisted of glycaemic measures. RESULTS: In response to episodes of adverse glycaemia, nursing action increased (proportion with nursing action: 45% to 73%; P<0.001), and medical action increased (proportion with medical action: 49% to 67%; P=0.011) with the glucose alert system in place. Patient-days with hyperglycaemia (any blood glucose value >15 mmol/l: 24% vs 16%; P=0.012) and patient-days with mean blood glucose >15 mmol/l (7.4% vs 2.6%; P=0.005) decreased. There was no difference in hypoglycaemia incidence. CONCLUSIONS: Use of a novel glucose alert system improved health professional responses to adverse glycaemia and decreased hyperglycaemia in the hospital setting.

Diabetes associated with immune checkpoint inhibition: presentation and management challenges.

BACKGROUND: In recent years, immune checkpoint blockade has become a standard therapy for a wide range of cancers. Adverse events including endocrinopathies result from the induction of autoimmunity. CASE REPORT: We report a case series of nine individuals who presented with immunotherapy-induced type 1 diabetes between 2015-2017. DISCUSSION: Onset of diabetes occurred within 12 weeks of commencing therapy. Anti- GAD antibodies were present in six people. Retrospective testing of islet antibodies in pre-treatment samples was possible in two people and this revealed anti-GAD seroconversion in the first and high anti-GAD titres pre and post-treatment in the second person. Six people had high risk HLA haplotypes. Clinical and genetic factors are described and compared with previously published cases. This article is protected by copyright. All rights reserved.

Fournier's gangrene in a man on empagliflozin for treatment of Type 2 diabetes.

BACKGROUND: Sodium-glucose cotransporter 2 (SLGT2) inhibitors has been associated with an increased risk of genital infections secondary to increased glycosuria. CASE REPORT: We report a case of a 41-year-old man with type 2 diabetes treated with empagliflozin and metformin who presented with scrotal swelling. He described multiple preceding episodes of genital thrush for which he self-administered over-the-counter anti-fungal treatment. On examination, he was afebrile and hemodynamically stable. Perineal examination revealed grossly swollen and indurated scrotum with bilateral inguinal lymphadenopathy. Investigations showed elevated inflammatory markers and HbA1c of 99 mmol/mol (11.2%). Computed tomography revealed features consistent with Fournier's gangrene. He underwent emergency exploration and debridement under anaesthetic with a later return to theatre for further exploration, washout and application of a vacuum dressing. He then received a split skin graft to his perineum. He required a 2-week course of intravenous antibiotics and was discharged home on oral antibiotics. Empagliflozin was ceased on admission and he was commenced on a basal bolus insulin regimen for glycaemic optimisation. CONCLUSION: There is a wide clinical spectrum of genital infections associated with SGLT2 inhibitors with most being generally mild and easily treated. However, risk factors such as diabetes, obesity, immunosuppressed states, smoking, alcohol abuse and end-stage renal or liver failure may increase the risk of potentially more severe infections such as Fournier's gangrene. Timely cessation of SGLT2 inhibitors in individuals with multiple risk factors may help prevent progression to more severe genital infections.

Factors associated with insulin-induced weight gain in an Australian type 2 diabetes outpatient clinic.

BACKGROUND: Insulin-induced weight gain is a key concern for people with type 2 diabetes (T2D) and their treatment team. This study aimed to document the prevalence of insulin-induced weight gain and its impact on cardiovascular risk factors in patients attending the Royal Melbourne Hospital diabetes clinic. METHODS: Clinical and biochemical data were extracted from a prospective clinic database and from the hospital record. These variables were correlated with the percentage weight change 1 year after starting insulin and compared between groups with or without clinically significant weight gain, defined as more than 7% of the baseline bodyweight. RESULTS: The population comprised 340 patients (184 male), representing 36% of people with T2D who commenced insulin at our clinic. Their mean ± SD age and duration of diabetes was 63 ± 11 and 13 ± 8 years respectively. The mean (95% CI) change in bodyweight at 1 year was 3.0 (2.5-3.5) kg, but this was not associated with deleterious changes in blood pressure or lipid profile. Weight gain was associated with higher insulin doses, the use of short-acting insulin and with lower baseline bodyweight. Clinically significant weight gain occurred in 87 patients and was associated with glucose-lowering regimens that included short-acting insulin or a thiazolidinedione, whereas regimens that incorporated other oral agents, particularly sulfonylureas, were associated with less weight gain. CONCLUSION: In this Australian tertiary hospital population with T2D, insulin-induced weight gain was common but was not associated with deleterious changes in blood pressure or lipids. Treatment regimens that avoid short-acting insulin but include oral agents other than thiazolidinediones might prevent insulin-induced weight gain in T2D.

Low prevalence of latent autoimmune diabetes in adults in northern India.

AIM: To study the frequency of islet antibodies in a large cohort of clinic- and community-based patients with Type 2 diabetes in northern India. METHODS: We measured glutamic acid decarboxylase (GAD) antibodies in 618 adults with Type 2 diabetes (378 patients with diabetes attending a hospital clinic, 240 patients diagnosed in a community survey) and in 192 healthy subjects residing in north India. Islet antigen 2 (IA2) antibodies were also studied in a proportion of the patients with diabetes (n = 492) and in a control population (n = 191). GAD and IA2 antibodies were measured by immunoprecipitation of the respective (35) S-labelled recombinant antigen. RESULTS: We found that GAD antibodies were present in nine (1.5%) patients with diabetes (clinic population: 0.8%, community study: 2.5%), a prevalence similar to that among the subjects without diabetes (n = 2; 1%). IA2 antibodies were detected in seven patients with Type 2 diabetes (1.4%) and in two healthy control subjects (1.0%). The frequency of either GAD or IA2 antibodies was similar in people with and without diabetes (3.2 vs 2.1%). No subject was found to have both antibodies. Insulin requirement was higher among antibody-positive than among antibody-negative patients (GAD antibody: 33 vs 6.3%; P = 0.001; GAD or IA2 antibody: 23.1 vs 6.4%; P = 0.02); however, other clinical features were similar in the two groups. CONCLUSIONS: In the present north-Indian population with Type 2 diabetes, the overall prevalence of GAD antibodies and the prevalence of either GAD or IA2 antibodies were considerably lower than those reported in white European populations.

Linkage disequilibrium of a type 1 diabetes susceptibility locus with a regulatory IL12B allele.

Type 1 diabetes (T1D; or insulin-dependent diabetes mellitus, IDDM) is an autoimmune disease with both genetic and environmental components. In addition to the human leukocyte antigen (HLA) complex, the single major genetic contributor of susceptibility, an unknown number of other unidentified genes are required to mediate disease. Although many loci conferring susceptibility to T1D have been mapped, their identification has proven problematic due to the complex nature of this disease. Our strategy for finding T1D susceptibility genes has been to test for human homologues of loci implicated in diabetes-prone NOD (non-obese diabetic) mice, together with application of biologically relevant stratification methods. We report here a new susceptibility locus, IDDM18, located near the interleukin-12 (IL-12)p40 gene, IL12B. Significant bias in transmission of IL12B alleles was observed in affected sibpairs and was confirmed in an independent cohort of simplex families. A single base change in the 3' UTR showed strong linkage disequilibrium with the T1D susceptibility locus. The IL12B 3' UTR alleles showed different levels of expression in cell lines. Variation in IL-12p40 production may influence T-cell responses crucial for either mediating or protecting against this and other autoimmune diseases.

New-onset diabetes after kidney transplantation-changes and challenges.

Despite substantial improvement in short-term results after kidney transplantation, increases in long-term graft survival have been modest. A significant impediment has been the morbidity and mortality attributable to cardiovascular disease (CVD). New-onset diabetes after transplantation (NODAT) is an independent predictor of cardiovascular events. This review examines recent literature surrounding diagnosis, outcomes and management of NODAT. Amongst otherwise heterogeneous studies, a common finding is the relative insensitivity of fasting blood glucose (FBG) as a screening test. Incorporating self-testing of afternoon capillary BG and glycohemoglobin (HbA(1c) ) detects many cases that would otherwise remain undetected without the oral glucose tolerance test (OGTT). Assessing the impact of NODAT on patient and graft survival is complicated by changes to diagnostic criteria, evolution of immunosuppressive regimens and increasing attention to cardiovascular risk management. Although recent studies reinforce a link between NODAT and death with a functioning graft (DWFG), there seems to be little effect on death-censored graft loss. The significance of glycemic control and diabetes resolution for patient outcomes remain notably absent from NODAT literature and treatment is also a neglected area. This review examines new and old therapeutic options, emphasizing the need to assess ß-cell pathology in customizing therapy. Finally, areas warranting further research are considered.

Glycaemic impact of patient-led use of sensor-guided pump therapy in type 1 diabetes: a randomised controlled trial.

AIMS/HYPOTHESIS: The objective of this study was to assess the impact of patient-led sensor-guided pump management on glycaemic control, and compare the effect with that of standard insulin pump therapy. METHODS: An open multicentre parallel randomised controlled trial was conducted at five tertiary diabetes centres. Participants aged 13.0-40.0 years with well-controlled type 1 diabetes were randomised 1:1 to either study group for 3 months. Randomisation was carried out using a central computer-generated schedule. Participants in the intervention group used sensor-guided pump management; no instructive guidelines in interpreting real-time data were provided ('patient-led' use). Participants in the control group continued their original insulin pump regimen. Continuous glucose monitoring (CGM) and HbA(1c) level were used to assess outcomes. The primary outcome was the difference in the proportion of time in the target glycaemic range during the 3 month study period (derived from CGM, target range 4-10 mmol/l). Secondary outcomes were difference in HbA(1c), time in hypoglycaemic (< or =3.9 mmol/l) and hyperglycaemic (> or =10.1 mmol/l) ranges and glycaemic variability. RESULTS: Sixty-two participants were recruited and randomised; 5/31 and 2/31 withdrew from intervention and control groups, respectively, leaving 26/31 and 29/31 for the intention-to-treat analyses. When adjusted for baseline values, the mean end-of-study HbA(1c) was 0.43% lower in the intervention group compared with the control group (95% CI 0.19 to 0.75%; p = 0.009). No difference was observed in CGM-derived time in target (measured difference 1.72; 95% CI -5.37 to 8.81), hypoglycaemic (0.54; 95% CI -3.48 to 4.55) or hyperglycaemic (-2.18; 95% CI -10.0 to 5.69) range or in glycaemic variability (-0.29; 95% CI -0.34 to 0.28). Within the intervention group, HbA(1c) was 0.51% lower in participants with sensor use > or =70% compared with participants with sensor use <70% (95% CI -0.98 to -0.04, p = 0.04). Five episodes of device malfunction occurred. CONCLUSIONS/INTERPRETATION: Individuals established on insulin pump therapy can employ sensor-guided pump management to improve glycaemic control. An apparent dose-dependent effect of sensor usage was noted; however, frequent use of this technology (> or =70%) was not universally acceptable. TRIAL REGISTRATION: ACTRN12606000049572

Markers on distal chromosome 2q linked to insulin-dependent diabetes mellitus.

Insulin-dependent diabetes mellitus (IDDM) is a multigenic autoimmune disease. An IDDM susceptibility gene was mapped to chromosome 2q34. This gene may act early in diabetogenesis, because "preclinical" individuals also showed linkage. Human leukocyte antigen (HLA)-disparate, but not HLA-identical, sibs showed linkage, which was even stronger in families with affected females. The genes encoding insulin-like growth factor-binding proteins 2 and 5 were mapped to a 4-megabase pair interval near this locus. These results indicate the existence of a gene that acts at an early stage in IDDM development, screening for which may identify a specific subset of at-risk individuals.

Effect of fenofibrate on the need for laser treatment for diabetic retinopathy (FIELD study): a randomised controlled trial.

BACKGROUND: Laser treatment for diabetic retinopathy is often associated with visual field reduction and other ocular side-effects. Our aim was to assess whether long-term lipid-lowering therapy with fenofibrate could reduce the progression of retinopathy and the need for laser treatment in patients with type 2 diabetes mellitus. METHODS: The Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study was a multinational randomised trial of 9795 patients aged 50-75 years with type 2 diabetes mellitus. Eligible patients were randomly assigned to receive fenofibrate 200 mg/day (n=4895) or matching placebo (n=4900). At each clinic visit, information concerning laser treatment for diabetic retinopathy-a prespecified tertiary endpoint of the main study-was gathered. Adjudication by ophthalmologists masked to treatment allocation defined instances of laser treatment for macular oedema, proliferative retinopathy, or other eye conditions. In a substudy of 1012 patients, standardised retinal photography was done and photographs graded with Early Treatment Diabetic Retinopathy Study (ETDRS) criteria to determine the cumulative incidence of diabetic retinopathy and its component lesions. Analyses were by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN64783481. FINDINGS: Laser treatment was needed more frequently in participants with poorer glycaemic or blood pressure control than in those with good control of these factors, and in those with a greater burden of clinical microvascular disease, but the need for such treatment was not affected by plasma lipid concentrations. The requirement for first laser treatment for all retinopathy was significantly lower in the fenofibrate group than in the placebo group (164 [3.4%] patients on fenofibrate vs 238 [4.9%] on placebo; hazard ratio [HR] 0.69, 95% CI 0.56-0.84; p=0.0002; absolute risk reduction 1.5% [0.7-2.3]). In the ophthalmology substudy, the primary endpoint of 2-step progression of retinopathy grade did not differ significantly between the two groups overall (46 [9.6%] patients on fenofibrate vs 57 [12.3%] on placebo; p=0.19) or in the subset of patients without pre-existing retinopathy (43 [11.4%] vs 43 [11.7%]; p=0.87). By contrast, in patients with pre-existing retinopathy, significantly fewer patients on fenofibrate had a 2-step progression than did those on placebo (three [3.1%] patients vs 14 [14.6%]; p=0.004). An exploratory composite endpoint of 2-step progression of retinopathy grade, macular oedema, or laser treatments was significantly lower in the fenofibrate group than in the placebo group (HR 0.66, 95% CI 0.47-0.94; p=0.022). INTERPRETATION: Treatment with fenofibrate in individuals with type 2 diabetes mellitus reduces the need for laser treatment for diabetic retinopathy, although the mechanism of this effect does not seem to be related to plasma concentrations of lipids.

Islet-reactive T cells are a marker of preclinical insulin-dependent diabetes.

The destruction of pancreatic islet beta cells in insulin-dependent diabetes mellitus (IDDM) is thought to be T cell mediated. To directly identify islet-reactive T cells in asymptomatic, "preclinical" IDDM individuals with islet cell antibodies (ICA), proliferation of peripheral blood mononuclear cells (PBMC) was measured in the presence of sonicated fetal pig proislets. Stimulation indices (mean +/- SD) for [3H]thymidine uptake by PBMC cultured with sonicated proislets were: preclinical IDDM subjects (n = 22) 6.10 +/- 6.50, recent-onset IDDM subjects (n = 29) 3.66 +/- 3.35, Graves' disease subjects (n = 6) 2.17 +/- 0.93, scleroderma subjects (n = 4) 1.65 +/- 0.19 and normal control subjects (n = 14) 1.63 +/- 0.62. 68% (15/22) of preclinical IDDM, 41% (12/29) of recent-onset IDDM and 17% (1/6) of Graves' disease subjects had T cell reactivity greater than the mean + 2 SD of controls. T cell reactivity to proislets was tissue specific, and greater in magnitude and frequency than to human insulin. The majority of preclinical subjects with ICA greater than 20 Juvenile Diabetes Foundation (JDF) units (12/15, 80%) or antibodies to a 64-kD islet autoantigen (11/15, 73%) had significant T cell reactivity to proislets. ICA greater than 40 JDF units, a strong prognostic marker for progression to clinical IDDM, was an absolute index of T cell reactivity. Overall, the frequency of T cell reactivity in preclinical subjects, 68% (15/22), was comparable to that of ICA greater than 20 JDF units or 64-kD antibodies. Greater T cell reactivity to proislets in preclinical subjects accords with the natural history of autoimmune beta cell destruction. The direct assay of islet-reactive T cells in peripheral blood may have prognostic significance for the development of clinical IDDM and should facilitate identification of the primary target autoantigen(s).

Disease sensitivity and specificity of 52 assays for glutamic acid decarboxylase antibodies. The Second International GADAB Workshop.

There is increasing interest in the use of glutamic acid decarboxylase antibodies (GADAbs) for identification of subjects at increased risk of developing insulin-dependent diabetes mellitus (IDDM). However, considerable variation exists between laboratories in the reported frequency of GADAb in various clinical situations, and disease sensitivity and specificity have not yet been compared between assays. An international workshop was held in which 101 coded freeze-dried sera, including 39 from subjects with newly diagnosed IDDM, 32 from healthy control subjects, 4 from nondiabetic subjects with Graves' disease, and 4 from islet cell antibody-positive subjects, were analyzed in 52 assays (radiobinding assay [RBA], 26; enzyme-linked immunosorbent assay [ELISA], 19; and enzymatic immunoprecipitation assay [EIP], 7). The mean sensitivity for RBAs (76.2%) was higher than for ELISAs (36.5%) and EIPs (49.9%) (P < 0.01). The mean specificity was similar for each assay format (RBA, 89.4%; ELISA. 89.4%; and EIP, 92.3%). The lower sensitivities of the ELISA and EIP were predominantly due to the inability of these assays to detect low levels of GADAb in IDDM. To convert results to standard units, standard curves were constructed using duplicate dilutions of the anti-glutamic acid decarboxylase monoclonal antibody MICA 3 and serum from a patient with stiff-man syndrome (SMS). Curves could be derived in 28 assays using the MICA 3 serum and in 29 using the SMS serum. The mean coefficients of variation between assays for disease and control samples were 45% when results were converted to MICA units, 77% for SMS units, and 76% for SD scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding of cytoplasmic islet cell antibodies is blocked by human pancreatic glycolipid extracts.

With biochemical and enzymatic treatment of frozen sections of pancreas, we have previously shown that cytoplasmic islet cell antibodies (ICAs) react with carbohydrate determinants of islet cell glycoconjugates. As a first step toward purifying these glycoconjugates, human pancreas tissue was extracted in a mixture of chloroform and methanol, and the glycolipids were obtained by effecting a Folch partition. The protein pellet, lipid fraction, and glycolipid fraction so obtained were assessed for their ability to block the binding of ICAs to frozen sections of human pancreas, the effect being quantitated with a photometer. Only the glycolipid extract could block ICA binding, and blocking was dose dependent. Subfractionation of the glycolipid extract by hydrophobic interaction on C18 cartridges demonstrated that blocking activity resided in the fraction bound and eluted with methanol, consistent with the autoantigen being a glycolipid. Furthermore, the binding of an anti-islet cell ganglioside monoclonal antibody, 3G5, could be blocked with these extracts, whereas the binding of an anti-islet cell protein monoclonal antibody, 4F2, was unaffected. The major gangliosides of the pancreas were seen to be GM3 and GD3 by thin-layer chromatography (TLC). Fractions scraped and eluted from TLC plates were tested for their ability to block ICA binding to pancreatic sections. Neither GM3- nor GD3-containing fractions could block ICA binding; however, a fraction containing minor pancreatic gangliosides (including GM2) of monosialoganglioside mobility was a potent inhibitor of ICA binding to pancreas sections. TLC of a chloroform-methanol extract of human islets demonstrated that islets differentially express monosialogangliosides (especially GM2).

64,000-Mr autoantigen in type I diabetes. Evidence against its surface location on human islets.

The sera of type I (insulin-dependent) diabetic subjects are reported to contain autoantibodies against a 64,000-Mr protein identified in [35S]methionine biosynthetically labeled pancreatic islet cells. We have attempted to localize this autoantigen to the surface of the beta-cell and to define its properties. Sera from 10 newly diagnosed type I diabetic subjects, including five of the index sera originally used to identify the autoantigen, were shown to specifically precipitate a reduced protein of 67,000 Mr from Triton-solubilized, surface 125I-labeled cultured adult human islet and rat insulinoma (RINm5F) cells but not from fresh rat spleen cells. Further characterization revealed that this protein was bovine serum albumin (BSA) adsorbed to cells from fetal calf serum (FCS)-supplemented culture medium and precipitated by BSA antibodies present in many diabetic sera. No labeled proteins were specifically precipitated when surface 125I-labeled and solubilized human islet or RINm5F cells were precleared with anti-BSA immunoglobulins or when cells were first cultured in human serum. In contrast, a 64,000-Mr protein, clearly not BSA, was precipitated by diabetic globulins from human islets but not from RINm5F cells labeled with [35S]methionine. In addition, a protein of the same size as well as proteins of approximately 35,000, 43,000, 140,000, and 200,000 Mr were specifically precipitated by diabetic globulins from freshly isolated human islets solubilized in Triton X-100 and then labeled with 125I. These findings suggest that the 64,000-Mr antigen is not expressed on the surface of human islet cells, at least in culture, and therefore question its relevance as a target for islet cell surface antibodies in initiating beta-cell damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of class I MHC proteins on RIN-m5F cells is increased by interferon-gamma and lymphokine-conditioned medium.

To examine whether products of the immune system interact with the pancreatic beta-cell, rat insulinoma cells (RIN-m5F line) were cultured in the presence of conditioned medium from concanavalin A-activated mouse spleen cells (CAS medium). Indirect immunofluorescence and flow cytometry revealed that after culture in CAS medium, RIN-m5F cells had an 8- to 10-fold increase in class I major histocompatibility complex (MHC) proteins, whereas class II MHC proteins remained undetectable, and the level of insulin and/or insulin-like growth factor 1 receptors was unchanged. The stimulation of class I MHC expression on RIN-m5F cells by CAS medium could be mimicked by recombinant interferon-gamma. Analysis of 125I-surface-labeled cells by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed that in the presence of CAS medium, there was a major increase in the expression of proteins of 48,000, 32,000, and 12,000 Mr and a minor increase in proteins of 17,000 and 9,000 Mr. Precipitation with monoclonal antibody identified the 48,000- and 12,000-Mr proteins as the class I MHC protein and beta 2-microglobulin, respectively. The ability of lymphokine-conditioned medium to increase the expression of RIN-m5F cell surface proteins, including the class I MHC proteins, provides a potential mechanism for enhancing the immune-mediated destruction of the beta-cell.

Increase in remission rate in newly diagnosed type I diabetic subjects treated with azathioprine.

Azathioprine (2 mg/kg) was given, in addition to routine insulin treatment, to alternate patients presenting with recent-onset type I diabetes. Treated (N = 13) and untreated (N = 11) patients did not differ significantly at diagnosis with respect to age, duration of symptoms, body weight, blood glucose, hemoglobin A1c, or presence of ketosis. Eight patients were treated for 12 mo, three elected to stop treatment at 6 mo, and treatment was stopped in two because of side effects. Seven treated patients had a remission compared with one untreated patient. At 12 mo these seven patients were distinguished by significantly higher basal and glucagon-stimulated levels of C-peptide (1.98 +/- 0.52 and 3.88 +/- 0.34 micrograms/L, respectively) compared with the other six treated patients (0.93 +/- 0.52 and 1.32 +/- 0.85 microgram/L, respectively), and by the persistence of islet cell cytoplasmic antibodies. Remissions were not sustained in the 1-2 yr after treatment, although relapsed patients required less insulin for control. These results corroborate those from nonrandomized trials using cyclosporine and suggest that protracted treatment with nonspecific immunosuppressive drugs may be necessary to avert insulin dependence.

High level of concordance between assays for glutamic acid decarboxylase antibodies. The First International Glutamic Acid Decarboxylase Antibody Workshop.

Glutamic acid decarboxylase antibodies (GADAbs) are being increasingly used in clinical and research programs for the prediction and classification of insulin-dependent diabetes mellitus (IDDM). A number of different assay formats for the measurement of GADAbs have been reported, but the degree of concordance between assays is unknown. In this study, GADAbs were measured on 16 coded sera in 34 assays to examine concordance between GADAb assays and establish the feasibility of an international GADAb standard of measurement unit. The 16 lyophilized coded samples consisted of sera from healthy control subjects (n = 2), IDDM patients (n = 3), a patient with polyendocrine autoimmunity (n = 1), and duplicate dilutions of plasmapheresis serum from a patient with stiff-man syndrome (SMS). A high level of concordance was found in the ranking of GADAb levels (P = 0.99, Friedman's test) in the samples. Thirteen (38%) assays could reproducibly distinguish dilutions of SMS serum and detect GADAbs in all IDDM and polyendocrine autoimmunity sera tested. Although assessed on only four samples, disease specificity was 100% in 29 assays. The majority of assays that immunoprecipitated radiolabeled GAD gave high results for sensitivity and specificity. Enzyme-linked immunosorbent assays and assays using immunofluorescence were generally less sensitive. Several assays, in particular those measuring GAD enzymatic activity immunoprecipitated in fluid phase from rat brain homogenate, showed a prozone-like phenomenon in the SMS dilution curve. Interpolation of results from a standard curve into workshop units resulted in relatively low scatter in samples with lower levels of GADAbs. Hence, the use of an international reference serum to enable comparison of results between laboratories appears feasible.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of cytoplasmic islet cell antigens by rat pancreas.

A major problem in standardization of the islet cell cytoplasmic antibody (ICA) assay is variation in sensitivity of the different human pancreas substrates used in individual laboratories. To circumvent this problem, we have developed an assay that utilizes Wistar-Furth rat pancreas as substrate, an anti-islet monoclonal antibody (A2B5) to identify islets and fluorescein-conjugated protein A to identify patient autoantibodies. Sera from 85 control subjects, 27 type I diabetics, and 17 subjects at high risk for developing type I diabetes were assayed in parallel with our standard ICA assay on human pancreas substrate and with Wistar-Furth rat pancreas as substrate. Two sera from control subjects (2 of 85) were ICA positive with rat pancreas compared to 1 of 85 with human pancreas substrate. Sera from 11 of 27 type I diabetics and 15 of 17 sera from high-risk subjects were ICA positive with either rat or human pancreas substrate. A correlation between the specific islet fluorescence readings on human and rat pancreas sections was found with sera from high-risk and control subjects. Furthermore, end-point titers of an ICA-positive serum were identical with both assays. Finally, incubation of an ICA-positive serum with glycolipids, extracted from either human or Wistar-Furth rat pancreas, blocked subsequent ICA binding. These findings suggest that Wistar-Furth rat pancreas expresses an identical or similar autoantigen to human pancreas.

Reactivity to human islets and fetal pig proislets by peripheral blood mononuclear cells from subjects with preclinical and clinical insulin-dependent diabetes.

A simple, direct assay for T-lymphocyte reactivity to islet antigen(s) in human insulin-dependent diabetes mellitus (IDDM) should facilitate preclinical diagnosis and the evaluation of intervention therapy to avert autoimmune-mediated beta-cell destruction. In subjects with preclinical or clinical IDDM, we measured the reactivity of peripheral blood mononuclear cells (PBMCs) incubated over 6 days with either adult human islets or fetal pig proislets, or other fetal pig tissues, and with human insulin. With islets, the stimulation index (SI) of [3H]thymidine uptake by PBMCs exceeded the mean + 2SD of control subjects in 6 of 6 preclinical subjects (SI 8.7 +/- 3.7), 7 of 11 clinical subjects (SI 5.2 +/- 3.4), and 1 of 12 control subjects (SI 2.7 +/- 1.7); with insulin, the responses were less in frequency and magnitude, being 4 of 6 (2.7 +/- 1.6), 3 of 11 (2.2 +/- 1.1), and 0 of 12 (1.20 +/- 0.55), respectively. The mean responses to islets of PBMCs from preclinical and clinical subjects differed significantly from control subjects (P less than 0.02 by 2-tailed Kruskal-Wallis test). Secretion of granulocyte macrophage colony-stimulating factor by PBMCs over 6 days was assayed in the preclinical group and generally paralleled the uptake of [3H]thymidine. PBMC reactivity to islets appeared to be at least as sensitive a marker of preclinical IDDM as autoantibodies to a 64,000-Mr protein, presumably the enzyme glutamic acid decarboxylase, in fetal pig proislets. In conclusion, islet-reactive T lymphocytes in subjects with preclinical and clinical IDDM can be identified in bulk culture of PBMCs.(ABSTRACT TRUNCATED AT 250 WORDS)