Islet cell antibodies (ICAs) are predictive of type I diabetes in first-degree relatives, but this immunohistochemical assay has proven difficult to standardize. As an alternative, we assessed the use of radioassays for antibodies against three molecularly characterized islet autoantigens, including ICA512bdc (amino acid residues 256-979 of the IA-2 molecule, incorporating the intracellular domain). We measured insulin autoantibodies (IAAs), GAD autoantibodies (GAAs), and ICA512bdc autoantibodies (ICA512bdcAAs) by radioassay, in addition to ICAs, in 882 first-degree relatives of patients with type I diabetes, 50 of whom later developed diabetes with a median follow-up of 2.0 years (maximum 11.3 years). The cutoff for each radioassay was determined by testing >200 control subjects. When autoantibody frequencies among the relatives were analyzed according to relationship to the proband, the offspring of diabetic fathers had a higher frequency of ICA5I2bdcAAs (P = 0.008), IAAs (P = 0.0001) and GAAs (P = 0.0001) than the offspring of diabetic mothers. ICA512bdcAAs and IAAs both showed a significant association with HLA-DR4-DQ8 (P = 0.0005). Among relatives developing diabetes, 98% had one or more of IAAs, GAAs, or ICA512bdcAAs, and 80% had two or more of these autoantibodies, compared with none of the control subjects. Using survival analysis to allow for different lengths of follow-up, there was a significant increase in the risk of diabetes with the number of these autoantibodies present, comparing zero, one, two, and three autoantibodies (P < 0.0001, log-rank test), and by Cox regression analysis, this was independent of ICAs and age. For relatives with two or more of these autoantibodies, the risk of diabetes within 3 years was 39% (95% CI, 27-52) and the risk within 5 years was 68% (95% CI, 52-84). Relatives with all three autoantibodies had a risk within 5 years estimated to be 100%. The presence of low first-phase insulin release further increased the risk for relatives with one or two autoantibodies. We conclude that the presence of two or more autoantibodies (out of IAAs, GAAs, and ICA512bdcAAs) is highly predictive of the development of type I diabetes among relatives.

No abstract

Background The Network for Pancreatic Organ donors with Diabetes was established to recover and characterize pancreata and related organs from cadaveric organ donors with various risk levels for type 1 diabetes (T1D). These biospecimens are available to investigators for collaborative studies aimed at addressing questions related to TID natural history and pathogenesis. Research design and methods Organ donors included T1D patients (new-onset to long-term), non-diabetic autoantibody positive subjects, non-diabetic controls, and individuals with disorders relevant to β-cell function. Pancreas recovery and transport met transplant-grade criteria. Additional samples recovered included serum, whole blood, spleen, and pancreatic and non-pancreatic lymph nodes. Biospecimens were processed for cryopreserved cells, fixed paraffin and fresh frozen blocks, and snap frozen samples. T1D autoantibodies, c-peptide levels, and high-resolution HLA genotyping for risk alleles were also determined. Results Over 160 donors have been enrolled (ages of 1 day to > 90 years). Standard operating procedures were established along with a quality management system. Donor demographics, laboratory assays, and histopathological characterizations were shared through an open online informatics system. Biospecimens were distributed to more than 60 investigators. Conclusions The nPOD program provides access to high quality biospecimens without cost to investigators. Collaborations and open data sharing are emphasized to maximize research potential of each donor. Based on initial successes, the nPOD program is expanding to recover additional organs relevant to T1D pathogenesis and complications from European countries (PanFin network).

It has been reported that an insulin 2 gene knockout, when bred onto nonobese diabetic (NOD) mice, accelerates diabetes. We produced insulin 1 gene knockout congenic NOD mice. In contrast to insulin 2, diabetes and insulitis were markedly reduced in insulin 1 knockout mice, with decreased and delayed diabetes in heterozygous females and no insulitis and diabetes in most homozygous female mice. Lack of insulitis was found for insulin 1 female homozygous knockout mice at 8, 12, and 37 weeks of age. Despite a lack of insulitis, insulin 1 homozygous knockout mice spontaneously expressed insulin autoantibodies. Administration of insulin peptide B:9 -23 of both insulin 1 and 2 to NOD mice induced insulin autoantibodies. Insulin 1 is not the only lymphocytic target of NOD mice. Insulin 1 homozygous knockout islets, when transplanted into recently diabetic wild-type NOD mice, became infiltrated with lymphocytes and only transiently reversed diabetes. These observations indicate that loss of either insulin gene can influence progression to diabetes of NOD mice and suggest that the preproinsulin 1 gene is crucial for the spontaneous development of NOD insulitis and diabetes.

No abstract

- Awareness of the gold standard paradox is necessary when using traditional pathologist scores to analytically validate a tIA tool because image analysis is used specifically to overcome known sources of bias in visual assessment of tissue sections.

No abstract

Aims/hypothesis Childhood diabetes is thought to usually result from autoimmune beta cell destruction (type 1A) with eventual total loss of beta cells. Analysis of C-peptide in children characterised at diabetes onset for autoantibodies shows heterogeneous preservation of insulin secretion in long-standing diabetes. The aim of this study was to characterise the pancreases of childhood-onset diabetes in order to define the pathological basis of this heterogeneity. Methods We evaluated 20 cadaveric organ donor pancreases of childhood-onset long-term patients for disease heterogeneity and obtained corresponding C-peptide measurements.Results Pancreases from the majority of cadaveric donors contained only insulin-deficient islets (14 of 20). The remaining six patients (30%) had numerous insulinpositive cells within at least some islets, with two different histological patterns. Pattern A (which we would associate with type 1A diabetes) had lobular retention of areas with 'abnormal' beta cells producing the apoptosis inhibitor survivin and HLA class I. In pattern B, 100% of all islets contained normal-appearing but quantitatively reduced beta cells without survivin or HLA class I. Conclusions/interpretation Our data demonstrate that C-peptide secretion in long-standing diabetic patients can be explained by two different patterns of beta cell survival, possibly reflecting different subsets of type 1 diabetes.