Clemens Jaeger

Comparative Analysis of Organ-Specific Autoantibodies and Celiac Disease—Associated Antibodies in Type 1 Diabetic Patients, Their First-Degree Relatives, and Healthy Control Subjects

OBJECTIVE In type 1 diabetes the coexistence with other endocrine diseases and organ-specific autoantibodies has been frequently reported leading to the concept of autoimmune polyendocrine syndrome (APS). In addition, an association of type 1 diabetes with celiac disease has been described. These disorders share a similar genetic background, and first-degree relatives of type 1 diabetic patients may also be affected significantly. Screening for specific antibodies allows early diagnosis of these disorders. RESEARCH DESIGN AND METHODS In the present cross-sectional study, we analyzed sera from 197 recent-onset type 1 diabetic patients at the time of diagnosis, 882 first-degree relatives, and sera of 150 healthy control subjects for prevalence and co-occurence of the following antibodies (method): insulin autoantibodies (radioimmunoassay); GAD and IA-2 antibodies (radioligand assay); islet cell antibody, anti-adrenal cortex antibodies, and anti-gastric parietal cell antibodies (indirect immunofluorescence); anti-thyroglobulin and anti-thyroid peroxidase antibodies; and gliadin IgG/A and tissue-transglutaminase IgA (enzyme-linked immunosorbent assay). RESULTS The overall frequency of gastric patietal cell antibodies and adrenal antibodies did not differ significantly among groups. In contrast, type 1 diabetes-associated antibodies and thyroid antibodies were significantly more frequent both in recent-onset type 1 diabetic patients and in the group of first-degree relatives (P < 0.05). The prevalence of gliadin IgG/IgA and transglutaminase IgA was significantly higher in the group of recent-onset type 1 diabetic patients (P < 0.05), but the difference between first-degree relatives and control subjects did not reach statistical significance. Focusing on the coexistence of antibodies, the group of recentonset type 1 diabetic patients presented with 27.4% of the subjects testing antibody-positive-specific for two or more of the envisaged disorders (i.e., type 1 diabetes, autoimmune thyroiditis, and celiac disease) compared with 3.1% in the group of first-degree relatives and 0 of 150 in the control population (P < 0.05). CONCLUSIONS We conclude that, in an active case-finding strategy, recent-onset type 1 diabetic patients should be routinely screened at least for concomitant autoimmune thyroid disease and additionally for celiac disease. Screening in their first-degree relatives should include at a minimum the search for thyroid autoimmunity in addition to screening for pre-type 1 diabetes.

High prevalence of exocrine pancreatic insufficiency in diabetes mellitus: A multicenter study screening fecal elastase 1 concentrations in 1,021 diabetic patients

Background: There have been numerous reports on pancreatic exocrine dysfunction in diabetes mellitus using either direct or indirect function tests. The measurement of fecal elastase 1 concentrations (FEC) has been used as a screening tool for exocrine pancreatic disease in different patient groups indicating a high prevalence of exocrine dysfunction in diabetic populations. In this study we had the opportunity to study more than 1,000 diabetic patients to confirm recent observations in smaller populations. Methods: FEC were measured by ELISA in 323 patients with type 1 and 697 type 2 diabetes mellitus. Subjects with a history of alcohol abuse, gastrointestinal surgery, cancer or inflammatory diseases were not included. Diabetes history and clinical data were recorded using a standard case report form. Findings: 1,021 patients (334 female, 687 male; mean age 50 years; mean diabetes duration 11 years; mean age at onset of diabetes 39 years) were studied. FEC was normal (>200 µg/g) in 59.3% and severely reduced (<100 µg/g) in 22.9%. There were significant differences between type 1 and type 2 patients as well as between insulin-treated and non-insulin-treated patients. Furthermore, there were weak associations between FEC and diabetes duration, age at onset of diabetes and body mass index, respectively. Interpretation: We could confirm that both type 1 and type 2 diabetic patients show pathological exocrine function in high prevalence. Exocrine insufficiency seems to be correlated to early onset of endocrine failure, long-lasting diabetes mellitus and low body mass index levels.

Progressive Islet Graft Failure Occurs Significantly Earlier in Autoantibody-Positive Than in Autoantibody-Negative IDDM Recipients of Intrahepatic Islet Allografts

Alloimmunity has been uncovered to be a cause of graft loss representing a major barrier for clinical islet transplantation, and several studies are designed to evaluate new strategies for immunosuppression to prevent alloimmunity. In contrast, the significance for autoimmune destruction of transplanted β-cells has remained somewhat controversial. Recently, two case reports based on histological findings have suggested recurrent autoimmune insulitis despite immunosup-pressive therapy both in clinical pancreas and in islet transplantation. In the present study, in 23 islet-grafted patients with IDDM receiving standard immunosuppressive therapy, we demonstrate that progressive impairment of islet graft function occurs significantly earlier in those individuals positive for autoantibodies as a typical stigma of diabetes-associated autoimmunity that is well established in the pre-diabetic periods of IDDM. Intraportal infusion of allo-geneic islets was performed in 23 C-peptide-negative IDDM patients, according to the clinical transplantation categories defined as islet after kidney (IAK) or simultaneous islet and kidney (SIK). Complete islet graft failure was defined as the 1st day of permanent C-peptide negativity in the serum (<0.2 ng/ml) and C-peptide negativity in the urine (<2 μg/dl). The median observation period following islet transplantation was 12 months (range 1–50) with a cumulative follow-up of 336 months. Islet cell antibodies (ICAs) and GAD65 antibodies were monitored before and regularly after islet transplantation. Kaplan-Meier survival analysis and log-rank statistics revealed a significant (P < 0.05) difference in cumulative islet graft survival depending on the presence of islet cell and/or GAD65 antibodies. These results strongly suggest that recurrent autoimmunity directed to transplanted β-cells contributes to islet graft failure despite sustained immunosuppression. For successful clinical islet transplantation in the future, new immunosuppressive therapies are needed to prevent both alloimmunity and autoimmunity.

High Prevalence of Steatorrhea in 101 Diabetic Patients Likely to Suffer from Exocrine Pancreatic Insufficiency According to Low Fecal Elastase 1 Concentrations: A Prospective Multicenter Study

Impaired exocrine pancreatic secretion has been frequently observed in diabetic patients by different methods, including direct function tests. However, the clinical importance remained unclear. In the present study, the fecal fat excretion in patients with type 1 or type 2 diabetes mellitus and exocrine dysfunction according to fecal elastase 1 concentrations <100 μg/g was investigated. Subjects with a history of gastrointestinal cancer, gastrointestinal surgery, alcohol abuse, or inflammatory diseases were excluded. In 101 patients the mean (±SD) fat excretion was 9.19 ± 5.39 g. Only 41 patients (40.6%) had normal fat excretion <7 g/day. In 40 patients (39.6%), it was higher than 10 g/day, indicating relevant steatorrhea. The fat excretion did not correlate with diabetes type, duration, or clinical symptoms. This finding is of some clinical importance and might influence pathophysiological concepts and the management of diabetic patients.

Islet cell antibodies and glutamic acid decarboxylase antibodies in patients with insulin-dependent diabetes mellitus undergoing kidney and islet-after-kidney transplantation

The humoral immune response to islet autoantigens, here defined by the presence of islet cell antibodies (ICA) and glutamic acid decarboxylase (GAD 65) antibodies, was studied in patients with long-term insulin-dependent diabetes mellitus (IDDM) receiving immunosuppressive therapy following kidney and islet-after-kidney transplantation. In a cross-sectional study of 30 kidney-grafted, long-term IDDM patients and 30 matched, nontransplanted IDDM controls, we observed a significant (P<0.05) decrease in ICA positivity by standard immunosuppressive therapy, but not in frequency or index levels of GAD 65 antibodies. Because of this intriguing finding, we investigated, in a pilot study on seven islet-after-kidney transplant recipients, the time course of frequency and levels of ICAs and GAD 65 antibodies relative to islet graft function. Stable islet graft function was seen in the patients with low GAD 65 antibody index levels, whereas rapid islet graft failure occurred in a patient with high GAD 65 antibody index levels prior to transplantation. In addition, GAD 65 autoimmunity reoccurred in one pretransplant antibody-negative patient 2 months after graft failure was noted. In conclusion, these observations suggest that beta-cell autoimmunity directed to GAD 65 can persist despite immunosuppressive therapy and may adversely affect islet graft function, possibly indicating disease recurrence as a major threat to successful clinical islet transplantation.

GAD 65 antibody but not ICA positivity in adult-onset diabetic patients is associated with early progression to clinical insulin dependency

Correct classification of diabetic patients in adulthood at the time of diagnosis is often difficult. Some may be initially diagnosed as having non-insulin-dependent diabetes mellitus and be treated with diet and/or oral hypoglycaemic agents (OHA) but later require insulin treatment. Islet cell antibodies and antibodies to GAD 65 have been associated with the development of insulin deficiency in this group of patients. In the present study, 150 patients with the initial diagnosis of type 2 diabetes mellitus in adulthood (30–60 years) were seen regularly over a period of 5 years in our diabetes outpatient clinic. Though treatment was started with diet or diet plus OHA, insulin therapy had to be introduced in a subset of patients. In all cases, serum obtained at the time of the initial diagnosis was analysed for islet cell antibodies and GAD 65 antibodies, as well as for thyroid and adrenal autoantibodies as possible markers for polyendocrine involvement. Islet cell antibody status, body mass index and the presence of thyroid and adrenal autoantibodies showed no significant correlation to subsequent insulin requirement (<2 years after diagnosis). In contrast, GAD 65 antibodies were significantly associated with the occurrence of clinical insulin dependency less than 2 years after the initial diagnosis (P<0.01), thus identifying a substantial proportion of patients requiring insulin therapy within the first 2 years after the diagnosis of type 2 diabetes. Determination of GAD 65 antibodies in patients with late-onset diabetes may contribute to their correct classification and adequate treatment.

Effect of transplantation site and culture pretreatment on islet xenograft survival (rat to mouse) in experimental diabetes without immunosuppression of the host.

Recently, we reported on indefinite islet graft survival in allotransplantation (rat to rat). This was achievable without the use of any immunosuppression by performing transplantation of culture-pretreated (22°C) islets of Langerhans under the renal capsule (r.c.) of chemically induced diabetic recipients. The aim of this study was to test this successful islet modulation technique in a xenogeneic animal model. Six groups of chemically induced diabetic, inbred, C57BL/6J mice received by transplantation either into the liver via the portal vein (i.po.) or under the renal capsule (r.c.) 300–350 either freshly or culture-pretreated (37°C and 22°C) Lewis rat islets without any immunosuppressive therapy. Histology was performed after rejection or post-transplant normoglycaemia (>120 days) for evaluation of the graft. Transplantation of freshly isolated islets resulted in 75% graft rejection 17 days after transplantation. Using culture pretreatment at 37°C, we noted 75% graft rejection 31 days after transplantation. In contrast, culture pretreatment at 22°C resulted in a marked prolongation of xenograft survival, 75% graft rejection occurring 58 days after transplantation, and in two cases there was indefinite graft survival (>120 days). Statistical analysis showed a significant prolongation of xenograft survival after culture pretreatment, with the most beneficial effect appearing after low-temperature culture at 22°C (P<0.05). Interestingly, xenograft survival was markedly prolonged only using the r.c. approach. Statistical comparison revealed a highly significant prolongation using the r.c. as transplantation site compared with i.po. (P<0.001). The prolongation was achievable by combining the r.c. as transplantation site and the culture pretreatment at low temperature (22°C). This effect is similar to the results in allotransplantation, but with a lower rate of indefinite graft survival.

Circulating cytokines are associated with human islet graft function in type 1 diabetes.

Islet cell transplantation has considerable potential as a cure for type 1 diabetes, but recurrent autoimmunity and allograft rejection in which both cytokines play an important role are major obstacles. Using a new approach considering confounders by regression analysis, we investigated circulating cytokines and their association with graft function in type 1 diabetes patients who underwent either simultaneous islet kidney (SIK) or islet after kidney (IAK) transplantation. After transplantation, interleukin (IL)-10 was lower in SIK recipients with subsequent loss of graft function in comparison to recipients maintaining graft function. Before transplantation, high IL-13 and IL-18 concentrations were prospectively associated for subsequent loss of graft function in IAK recipients, whereas in SIK recipients, high macrophage migration inhibitory factor (MIF) concentrations were associated with subsequent loss of graft function. Circulating cytokines are associated with islet graft function in patients with long-standing type 1 diabetes when considering confounders.