Cytoplasmic Islet Cell Antibodies Research Articles

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).

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

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

Autoantibodies to insulin are present in sera of patients with autoimmune thyroid disease.

It has been clinically suspected that patients with autoimmune thyroid disease are at an increased risk of developing other autoimmune diseases later in life. To determine the presence and potential importance of a more generalized deregulation of immune response in patients with Grave's disease and Hashimoto's disease, sera from 33 patients with Graves' disease and 16 patients with Hashimoto's disease were screened for the presence of anti-insulin antibodies and anti-insulin-receptor antibodies. An enzyme-linked immunosorbent assay was used to identify the presence of IgG against human insulin. The optical density indicating the presence of IgG against insulin in sera from patients with Graves' disease averaged .172 +/- .024 (mean +/- SE; range .010-.802), compared to the mean normal value of .098 +/- .0009 (range .012-.238) in 33 control subjects. Ten of 33 patients with Graves' disease had values greater than .200, whereas control sera values were less than .200 in all but one case (P less than .005, Graves' sera vs. controls). The sera from patients with Hashimoto's disease had a mean optical density of .110 +/- .016, with 15 of 16 values between .010 and .200. These values were not significantly different from controls with an insulin-binding inhibition assay. Anti-insulin-receptor antibodies were not detected in any of 33 patients with Graves' disease, and cytoplasmic islet cell antibodies were not detected in sera from seven patients with Graves' disease who had insulin-binding antibodies. These data support the hypothesis that the immunologic response in autoimmune thyroid disease may be more heterogeneous and polyclonal than previously believed.

Cross-species Reactivity of Pancreas Antigens with Islet Cell Cytoplasmic Antibodies in Sera from Patients with Type 1 (Insulin-dependent) Diabetes Mellitus

Cross-species Reactivity of Pancreas Antigens with Islet Cell Cytoplasmic Antibodies in Sera from Patients with Type 1 (Insulin-dependent) Diabetes Mellitus

Assay for cytoplasmic islet cell antibodies using two-color immunofluorescence and rat pancreas.

A major problem in standardization of the islet cell cytoplasmic antibody assay (ICA) is variation in sensitivity of the different human pancreas substrates used in individual laboratories.

Quantitative assay for human cytoplasmic islet cell antibodies

Quantitative assay for human cytoplasmic islet cell antibodies

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.

Progress Toward Standardization of Cytoplasmic Islet Cell–Antibody Assay

Cytoplasmic islet cell autoantibodies (ICAs) of 13 coded sera were determined by 26 laboratories. ICAs were determined by 24 laboratories according to a standard protocol based on the conventional indirect-immunofluorescence technique on cryostat sections of human pancreas. In addition, these 24 laboratories had performed any of 8 modifications of the assay. Test samples were titrated to end point, and the results obtained with the different methods were compared with those obtained by the standard protocol. The remaining 2 laboratories used either exclusively pancreatic sections of monkey instead of human as substrate (lab 23) or applied immunohistochemical staining (lab 22). By following the standard protocol, interlaboratory concordance was greater than 90% for the presence or absence of islet cell antibodies in 7 of the 13 samples circulated. However, a wide variability of titers was recorded, ranging from negative to 128. Of the modifications, prolonged incubation in the presence of aprotinin was performed by 10 laboratories and was found to improve the sensitivity in 57 of 70 (81%) determinations with samples that had been ICA positive by the standard protocol. Improved sensitivity was also noted by 2 laboratories with sections of monkey pancreas. Acetone-fixed sections, used by 6 laboratories, or a two-color immunofluorescence method, applied by 3 laboratories, did not change the titers in 27 of 35 (77%) and 14 of 25 (56%) determinations with samples that had been ICA positive by the standard protocol. In contrast, heat inactivation of the samples before testing, performed by 5 laboratories, resulted in a decrease in titers in 25 of 39 (64%) determinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunology and Diabetes Workshops: Report of the Second International Workshop on the Standardisation of Cytoplasmic Islet Cell Antibodies

Immunology and Diabetes Workshops: Report of the Second International Workshop on the Standardisation of Cytoplasmic Islet Cell Antibodies

抗ラ氏島細胞質抗体(islet cell cytoplasmic antibodies)およびその対応抗原の性状に関する免疫化学的研究

抗ラ氏島細胞質抗体(islet cell cytoplasmic antibodies)およびその対応抗原の性状に関する免疫化学的研究

Epidemiology of insulin-dependent diabetes mellitus in Canterbury, New Zealand

A prospective study of incidence and prevalence of insulin-dependent diabetes mellitus in persons under 20 years was conducted over a 4-year period (1 February 1982-1 February 1986) for the Canterbury Hospital Board (total population 342,000) area in New Zealand. A central register for the area was established at the beginning of the study period. Degree of ascertainment was close to 100%. Average annual incidence was 11.7 persons per 100,000 (females: 10.6 per 100,000; males: 12.7 per 100,000) with no significant sex difference or temporal trends. Incidence peaks were seen for both sexes in the pubertal ages (females: 11 years; males: 13 years), with minor peaks occurring for both sexes in the pre-school ages. Age of onset was significantly younger in females than males. A seasonal variation in incidence was seen for males, with peaks in late autumn and mid-winter. 5.7% of the new diabetics had a first-degree relative with insulin-dependent diabetes mellitus. Islet cell cytoplasmic antibodies were detected in 68% of new diabetics and in 0% of age- and sex-matched healthy controls. Thyroid, gastric and adrenal auto-antibodies were seen more frequently in diabetics than in controls, but this difference was not significant. Prevalence of insulin-dependent diabetes on 1 February 1982 was 1.00 per 1000 and 1.05 per 1000 on 1 February 1986. The insulin-dependent diabetes mellitus incidence characteristics noted for the Canterbury Hospital Board area are similar to those reported for European and North American populations.

Rubella virus-induced diabetes in the hamster.

The congenital rubella syndrome provides the best documentation in humans that a viral infection is associated with the subsequent development of insulin-dependent diabetes mellitus. We have developed an animal model in neonatal golden Syrian hamsters infected with rubella virus passaged in beta-cells that closely parallels the diabetes observed with congenital rubella. The hamsters develop hyperglycemia and hypoinsulinemia, which are sustained throughout the 15-wk study period. A mononuclear infiltration of the islets, isolation of rubella virus from whole pancreas, the presence of viral antigen in beta-cells by immunofluorescent localization, and cytoplasmic islet cell antibodies (40%) are demonstrated. These data suggest that an autoimmune process and diabetes develop after rubella virus infection in neonatal hamsters. This model may uncover the precise mechanism by which rubella virus induces similar disease in humans.

Are insulin autoantibodies markers for insulin-dependent diabetes mellitus?

Recent studies have shown that insulin autoantibodies occur in patients with newly diagnosed insulin-dependent diabetes mellitus (IDDM) before exogenous insulin treatment. Our study was designed to test the hypothesis that insulin autoantibodies, like cytoplasmic islet cell antibodies (ICAs), can identify individuals with ongoing autoimmune beta-cell destruction and increased risk of IDDM development. Insulin autoantibodies detected by use of a radioligand-binding assay were found in 1.4% of normal controls, 4% of first-degree relatives of IDDM patients, and in 37% of newly diagnosed IDDM patients. A strong positive correlation between insulin autoantibodies and ICAs was observed. HLA typing of insulin-autoantibody-positive first-degree relatives of IDDM patients, as well as in the general population, revealed a strong association with HLA-DR3 and/or-DR4, suggesting that insulin autoantibodies are restricted to persons genetically susceptible to IDDM. In an ongoing study of beta-cell function in ICA-positive nondiabetic individuals, the additional presence of insulin autoantibodies significantly increased the likelihood of beta-cell dysfunction. After intravenous glucose stimulation, insulinopenia was present in 70% of ICA and insulin-autoantibody-positive individuals in contrast to only 23% of ICA-positive, insulin-autoantibody-negative persons. These data document a significant association between insulin autoantibodies and ICAs and support the contention that insulin autoantibodies, like ICAs, are markers of ongoing beta-cell destruction.

Islet cell and other organ-specific autoantibodies in healthy first-degree relatives to insulin-dependent.

The presence of organ-specific autoantibodies including islet cell surface, cytoplasmic and cytotoxic as well as thyroid-gastric antibodies were determined in healthy, non-diabetic, first-degree relatives to 30 insulin-dependent diabetic (IDDM) children. Thirty healthy families without family-history of diabetes mellitus served as controls. The prevalence of organ-specific autoantibodies among the healthy members in the diabetic families was increased compared to the control families (p less than 0.005). Islet cell cytoplasmic antibodies were only detected in diabetes families, since 23% (7/30) of the probands and 7% (2/31) of the siblings were positive and all others negative. Organ-specific autoantibodies were associated with HLA DR3 only in the diabetes families (p less than 0.025) while autoantibody positive members in the control families were associated with HLA B7 (p less than 0.01). This study suggests that childhood IDDM occurs in families with an increased prevalence of organ-specific autoantibodies.

Gestational Diabetes Mellitus: A Syndrome with Phenotypic and Genotypic Heterogeneity

One hundred ninety-nine gravida with gestational diabetes mellitus (GDM) defined as "carbohydrate intolerance of varying severity with onset or first recognition during pregnancy" have been stratified into subgroups on the basis of fasting plasma glucose and evaluated for further phenotypic and genotypic heterogeneity. A significantly greater proportion of the women in all our groups were older and heavier than in a "control" population of 148 consecutive gravida with documented normal oral glucose tolerance. After correction for age and weight by covariate analysis, absolute insulinopenia in response to oral glucose could be demonstrated in all GDM groups, although exceptions were present in each. The incidence of diabetes in the mothers of our patients with GDM was 8-fold greater than in controls; the incidence in fathers did not deviate from control patterns. HLA-DR3 and DR4 antigens were more frequently present in GDM and the increase was statistically significant in blacks. At the time of diagnosis, cytoplasmic islet cell antibodies (ICA) were significantly more common in GDM associated with elevated fasting plasma glucose than in controls; the frequency of ICA was 18.4% (7/38) in women with fasting plasma glucose greater than or equal to 130 mg/dl. Our findings indicate that GDM entails genotypic as well as phenotypic diversity and may include patients with slowly-evolving Type I diabetes mellitus, as well as patients with Type II diabetes mellitus, and women with asymptomatic diabetes which antedated the pregnancy (i.e. pregestational diabetes mellitus). Appreciation of this heterogeneity should be incorporated into any evaluation of intervention strategies for women with GDM or into prognoses concerning their postpartum metabolic status.

Relation between insulin antibody and complement-fixing islet cell antibody at clinical diagnosis of IDDM.

To test the hypothesis that insulin-binding antibodies (IBAs) appearing in the circulation before insulin treatment are markers of beta-cell damage, we studied the prevalence of IBAs and both conventional (IF-ICAs)-and complement (CF-ICAs)-fixing cytoplasmic islet cell antibodies in 60 newly diagnosed diabetic children with a mean age of 9.5 yr. Seventeen (28.3%) had an insulin binding exceeding the upper range (2.8%) of that observed in 68 age-matched controls. The IBA-positive subjects were characterized by a younger age of onset [6.2 +/- 4.0 (SD) vs. 10.8 +/- 3.2 yr; P less than 0.001], lower glycosylated hemoglobin A1 levels (14.1 +/- 3.1 vs. 16.0 +/- 3.0%; P less than 0.05), lower serum C-peptide concentrations (0.12 +/- 0.07 vs. 0.20 +/- 0.17 nmol/L; P less than 0.05), and an increased frequency of HLA-Dw4 (9/13 vs. 11/37; P less than 0.05). There was no significant relation between IBAs and serum C-peptide concentrations after age adjustment by multiple regression analysis. Forty-three children (75%) were positive for IF-ICA and 38 (63.3%) for CF-ICA. Twelve IBA-positive diabetics (70.6%) had IF-ICA as well as CF-ICA in their serum. No association could be observed between IBA and either IF-ICA or CF-ICA, however. The results suggest that IBAs developing before diagnosis serve as an indicator of clinical and genetic heterogeneity within IDDM rather than as a marker of autoimmune beta-cell destruction.

A re-examination of islet cell cytoplasmic antibodies in diabetic dogs

Serum samples were obtained from 48 dogs with recently diagnosed untreated diabetes mellitus. Serums were tested for cytoplasmic autoantibodies to normal canine pancreatic islet antigens by indirect immunofluorescence, peroxidase-anti-peroxidase, and avidin-biotin complex, immunohistochemistry. Autoantibodies were not detectable in any of the samples. Serums were also examined from 20 diabetic dogs maintained on exogenous insulin therapy for periods of one month to five years. Positive reactions were seen in 11 dogs. These positive responses were completely absorbed by preincubation of serums with commercial insulin preparations or with purified pork or beef insulin. Newly diagnosed diabetic dogs do not have readily detectable autoantibodies to islet cytoplasmic antigens. Our previous report (Haines and Penhale, 1985) of islet antibody in diabetic dogs with unknown clinical histories was likely demonstrating antibody to insulin in patients treated with exogenous insulin. Antibodies to insulin were detected in approximately half of the insulin treated dogs tested. These antibodies were induced by commercial beef and pork insulin preparations and were found to be broadly cross-reactive recognizing epitopes on canine, bovine and porcine insulins.

Immunology and Diabetes Workshops: report of the first international workshop on the standardisation of cytoplasmic islet cell antibodies

Ce troisieme workshop s'est attache a determiner la precision des differents laboratoires, la specificite des anticorps anti-ilots, l'amelioration des concordances interlaboratoires en utilisant les standards JDF, et l'expression des resultats avec des unites arbitraires

Islet cell antibodies and the development of diabetes mellitus in relation to mumps infection and mumps vaccination.

Islet cell antibodies were investigated in 127 non-diabetic children after mumps infection and in four out of seven children who developed diabetes mellitus shortly after active mumps vaccination. Twenty-one of the children who had mumps and all four vaccinated children who were tested had islet cell cytoplasmic antibodies. In contrast, islet cell surface antibodies were detected in 43 out of 68 patients with mumps infection and in 32 out of 44 patients with other viral diseases. All but one mumps-infected child and all the other viral infected patients investigated did not develop diabetes mellitus. The mumps-infected ICA positive children did not show those HLA-frequencies associated with Type 1 diabetes.

Triad of Markers for Identifying Children at High Risk of Developing Insulin-Dependent Diabetes Mellitus

A longitudinal investigation was conducted from 1977 to 1984 on 178 families in which one or more of the children had insulin-dependent diabetes mellitus. Of 351 nondiabetic sibs followed up for an average of 54 months, ten have, thus far, become diabetic. Eight sibs were HLA identical to their diabetic proband and nine had HLA-DR3 and/or HLA-DR4. Islet cell surface antibody and islet cell cytoplasmic antibody were found from two to 74 months before the onset of clinical diabetes in 100% and 90%, respectively, of the children. A decrease in insulin secretion was observed in all of these children on entry into the study and was detected in the absence of elevated plasma glucose concentrations. The data suggest that the triad of HLA identity, pancreatic islet cell antibodies, and depressed insulin secretion identifies those sibs who are at high risk of developing insulin-dependent diabetes mellitus.