Islet Cell Surface Antibodies Research Articles

インスリン非依存型糖尿病におけるすい島細胞膜抗体（ＩＣＳＡ）の臨床的意義 すい島Ｂ細胞機能そしてＨＬＡ抗原との関連

インスリン非依存型糖尿病におけるすい島細胞膜抗体（ＩＣＳＡ）の臨床的意義 すい島Ｂ細胞機能そしてＨＬＡ抗原との関連

Prevalence of Islet Cell Antibodies (ICA) and Islet Cell Surface Antibodies (ICSA) in Children and Adolescents with Antecedent Mumps Infection1)

There is good evidence that viruses may play a role in some animal models of diabetes. Since mumps virus seems to be the most likely candidate, we studied the possible relationship of islet cell antibodies, islet cell surface antibodies and glucose tolerance in 86 children and adolescents in whom mumps infection had occurred 14 months previously. Impaired glucose tolerance was diagnosed in 3.5% (n = 3) but symptomatic diabetes did not appear. No relationship existed between complications of antecedent mumps infection (pancreatitis, orchitis, meningitis) and glucose tolerance. The prevalence of ICA and ICSA was 78% and 36%, respectively. The simultaneous prevalence of ICA and ICSA was 33%. The pathogenetic role of mumps infection and ICA/ ICSA and their possible relation to slow progressive beta cell destruction remains to be elucidated.

Islet cell antibodies in individuals at increased risk for IDDM.

Islet cell cytoplasmic antibodies (ICA), islet cell surface ( ICSA ) antibodies, HLA phenotypes, glucose tolerance, insulin secretion, and insulin sensitivity were studied in 16 twins of insulin-dependent diabetics as well as in 21 subjects with impaired glucose tolerance (IGT). 60% of the identical twins and 40% of the non-identical twins were ICSA -positive. The prevalence of ICSA in control persons was only 5%. ICA were found in all identical twins and in half of the non-identical twins. However, ICSA and ICA results were concordant in only 46% of the whole group of twins. There was no correlation between ICSA and either insulin secretion or insulin sensitivity. In the IGT subjects exhibiting low and normal insulin responses ICSA were observed in 67% and 23%, respectively. A high proportion of twins, but not of IGT subjects, had HLA DR3 or DR4 antigens which seem to confer genetic susceptibility to the development of IDDM. In the majority of DR3/DR4 twins, ICSA were also present. This might support the hypothesis of genetically-based autoimmunity, although the precise relationship between HLA and islet cell antibodies has to be clarified in a prospective study.

Islet cell surface antibodies (ICSA) in subjects with a previous mumps infection--a prospective study over a 4 year period.

It has been suggested that the mumps virus may be involved in the etiopathogenesis of Type-I diabetes mellitus. Most studies have analyzed this relationship retrospectively. We, however, carried out a prospective study over a 4 year period after a mumps infection in two age groups (16 years and under [group A no = 32] and over 16 years [group B no = 18]). These subjects with "diabetic risk factors" (impaired glucose tolerance, low insulin response, ICSA and/or HLA-DR3/DR4) were selected from 1581 registered cases, in whom an antecedent mumps infection had occurred in 1980 and 1981. Glucose tolerance and insulin secretion did not change significantly during 4 years after a mumps infection. Overt diabetes was not observed in any of the cases. One year after a mumps infection 35% of children and 63% of adolescents/adults exhibited ICSA (control subjects = 5%; a serum was considered ICSA-positive if more than 25% of the intact rat islet cells showed distinct cell surface immunofluorescence). After 4 years the percentage of subjects with ICSA decreased significantly to 13% and 14%, resp. Only 21% of ICSA-positive sera were found to be cytotoxic on rat islet cells (51Cr-release assay). No relationship could be evaluated between complications resulting from a mumps infection and the appearance of ICSA. There was no correlation between ICSA, glucose tolerance, and insulin secretion. In fact, our prospective study did not reveal any relationship between a mumps infection and Type-I diabetes. ICSA would seem to be of no predictive value.

Islet Cell Transplantation in Type I Diabetes Mellitus: Evaluation of Humoral Immune Response

Four males and three females ranging in age from 20 to 35 years and afflicted with complicated Type 1-diabetes for more than 8 years underwent islet cell allotransplantation (ATx, 6 cases) and xenotransplantation (XTx, 1 case). Precultured islet cells derived from human or bovine fetal pancreata were injected into the m. rectus abdominis. Immunosuppression was not applied. Plasma C-peptide and islet cell surface antibodies (ICSA) were continually measured both before and until the twentienth week following islet cell transplantation. All recipients were subdivided as "responsive" (RR, 3 males) or "non-responsive" (NRR, 1 male and 3 females), according to the dynamics of their ICSA levels. All 3 RR (1XTx and 2 ATx) showed a peak of ICSA two weeks after cell injection. Subsequent ICSA levels had the tendency to either diminish or increase. Heterogeneity of preoperative antibody level, especially in NRR, was also observed. No associations between ICSA and ATx or XTx, age at diabetes onset, or duration of the disease was found. Only one RR with XTx had a reduced daily insulin requirement and a significant C-peptide response similar to the dynamics of ICSA levels. A greater mass of available bovine islet cells might be responsible for this effect.

Generation and partial characterization of monoclonal antibodies reactive with islet cell antigens.

Islet cell antibodies have been detected in more than 60% of newly diagnosed type I diabetics. Their pathogenetic role is still unclear. We have generated monoclonal antibodies (mc-ab) reactive with islet cell antigens by fusing mouse myeloma cells with spleen cells from Balb/c mice immunized with pancreatic islet cells. Hybridomas producing islet cell surface antibodies (ICSA) were detected by indirect immunofluorescence on viable cells from rat islets or rat insulinoma. Cytoplasmic islet cell antibodies (ICA) were detected by indirect immunofluorescence on Bouin-fixed sections of mouse pancreas. The ICSA- and/or ICA-producing hybridomas were cloned twice by limiting dilution. This paper describes six different mc-ab. All hybrid cell lines obtained produced IgM antibodies. Four of them mediate complement-dependent cytotoxicity to viable rat islet cells. In the present study the heterogeneity of circulating ICSA is demonstrated. Also, a monoclonal beta cell surface autoantibody K56aF3 was produced by fusion of spleen cells from a mouse treated with sub-diabetogenic doses of streptozotocin in combination with complete Freund's adjuvant. It was cytotoxic against islet cells up to a dilution of 1:1,000 and it could inhibit the insulin secretion from neonatal rat islets cultured in RPMI 1640 as stimulated by glucose or by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine common with glucose. The latter effect was reversible as indicated by the recovery of insulin secretion in a subsequent culture period without mc-ab. These results suggest that circulating ICSA in type I diabetics may alter beta cell function and thereby contribute to the pathogenesis of type I diabetes.

Metabolic, Hormonal, and Immunological Alterations in Subjects with Antecedent Mumps Infection

Since mumps virus seems to be one of the most likely candidates in viral etiology of insulin-dependent diabetes (IDDM) we studied the possible relationship of glucose tolerance (75 g oGTT), beta cell function, diabetes associated HLA antigens, haptoglobin phenotype, islet cell antibodies (ICA) and islet cell surface antibodies (ICSA) in 125 subjects with antecedent mumps infection. Impaired glucose tolerance (IGT) was diagnosed in 3.2% (n = 4) but onset of diabetes did not appear within 14 months after mumps infection. There was no relationship between glucose tolerance and complications of antecedent mumps infection (e.g. pancreatitis, meningitis, orchitis). The prevalence rate of ICA was 76%. ICSA were detectable in about 36% of children and 62% of the adults tested (p less than 0.01). There was no relationship between ICA/ICSA and diabetes-associated HLA antigens, haptoglobin phenotype or beta cell function (fasting C-peptide and insulin response to 75 g oGTT). However, adults with circulating ICA were characterized by a significantly lower insulin response to glucose. Fifty two "risk" subjects characterized by IGT, diabetes associated HLA antigen(s), ICA or ICSA either alone or combined were studied again 26 months after mumps infection. No symptomatic diabetes appeared and IGT was diagnosed in one case only. ICA and ICSA persisted in more than 50% of subjects in whom ICA or ICSA were present 14 months after mumps infection. Since the used immunological techniques do not clearly distinguish organ-specific from non-organ-specific antibodies the results must be interpreted with caution. To summarize, the preliminary results do not support a close temporal relationship between mumps infection and the onset of IDDM. The pathogenetic role of mumps virus and ICA/ICSA and their possible relation to a slow progressive beta cell destruction has still to be determined.

Inhibition of glucagon release of isolated islets of Langerhans by monoclonal antibodies.

The presence of islet cell cytoplasmic antibodies (ICA) and islet cell surface antibodies (ICSA) at the time of diagnosis of type 1 (insulin-dependent) diabetes mellitus has been taken as evidence that autoimmune mechanisms are involved in the pathogenesis of the disease. The demonstration that ICSA in the presence of complement are preferentially lytic for beta-cells may be important in defining the role of these autoantibodies in the pathogenesis of type 1 diabetes. Because of the polyclonality of the immune response, the ICA and ICSA molecules of diabetic patient vary enormously in their binding parameters. For this reason we have generated monoclonal antibodies (MC-Ab) to islet cell antigens. In this study we investigate the effect of the two MC-Ab K28 A1 and K28 D6 resulted from the same fusion of the P3-X63-Ag8 murine myeloma cell line with the spleen cells of a Balb/c mouse immunized with rat islet cells on the hormone release of isolated rat islet in co-culture with the antibody-secreting hybridomas. The MC-Ab K28 D6 binds to both islet cell cytoplasmic and surface antigens, the K28 A1 is only reactive with cytoplasmic antigens. Surprisingly, in contrast to the monoclonal antibody K28 A1, K28 D6 enhanced the glucagon content and diminished the insulin secretion of the islets. Either the K28 D6 is directed to an epitope occurring on the beta- as well as alpha-cells or the antibody-mediated inhibition of the glucagon release results in a significantly reduced insulin secretion.

Islet Cell Antibodies and Viral Infections

The sera of 127 non-diabetic children after mumps-infection were investigated for the presence of islet cell antibodies and islet cell surface antibodies. The study also included 4 children who developed diabetes mellitus shortly after an active mumps vaccination. 21 of the non-diabetic children and four of the vaccinated children exhibited islet cell cytoplasmic antibodies. Islet cell surface antibodies were observed more frequently, namely in 43 out of 68 patients studied after mumps infection and in 32 out of 44 patients studied after different viral diseases. With one exception, none of the mumps-infected children and none of the other viral infected patients developed diabetes mellitus.

Autoimmune Reactions in a Patient with Malignant Insulinoma Treated by Multiple Low Dose Streptozotocin*)

A 66-year-old female patient with a malignant insulinoma was treated with streptozotocin (STZ; Zanosar) in 5 cycles every 4 weeks as 5 day courses with an intravenous dosage of 850 mg per day. Under this treatment hypoglycemic episodes decreased continuously in number as well as severity and - after a delay of 12 months after the last treatment - an overt diabetes mellitus appeared. Plasma insulin concentrations dropped immediately after starting of STZ therapy. On the other hand, islet cell surface antibodies and their complement-dependent cytotoxicity increased continuously, being at their highest 6 months after termination of STZ treatment. Thus, STZ is able to induce a specific immune response against islet cells with a progressive damage of malignant insulin producing cells.

Complement-mediated cytotoxic effects of islet cell surface antibodies in non-diabetic subjects with antecedent mumps infection and diabetic risk.

We studied sera of 24 selected non-diabetic subjects in whom an antecedent mumps infection with either complications and/or with onset at older age occurred 10-27 month ago regarding the capability to lyse rat islets of Langerhans in vitro. Thirteen subjects were characterized by diabetes associated HLA antigens DR3 and/or DR4 whereas 11 of them had none of these HLA antigens. Islet cell surface antibodies (ICSA) could be detected in 11 out of 24 subjects. Isolated pancreatic islets from 8-10 days old Wistar rats were incubated in freshly prepared human serum. The insulin leakage under the conditions of pharmacologic blockade of insulin secretion by means of epinephrine and propranolol provides a measure of complement-mediated cytotoxicity of human serum against rats islets in vitro. Out of a total of 24 subjects the sera of 11 of them exhibited cytotoxicity. Mean cytolytic insulin leakage was significantly higher in subjects with DR3 and/or DR4 in comparison with subjects without these HLA antigens (6.82 +/- 0.77% vs 3.90 +/- 0.48%; p less than 0.05). Ten out of the 11 subjects with cytotoxic sera had HLA DR3 and/or DR4 whereas DR3 was present in three out of 13 subjects with non-cytotoxic sera. There was no relationship between beta cell function in vivo (fasting C-peptide concentration and insulin response to oral glucose challenge) and the capability of patients sera to damage islet cells in vitro. In conclusion the pathogenetic role of mumps virus and cytotoxic ICSA and their possible relation to slow progressive beta-cell destruction has still to be ascertained.

The Frequency of Islet Cell Surface Antibodies and Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) of Mononuclear Cells in HLA-Typed Patients with High Diabetes Risk*

To evaluate the significance of ICSA as a prognostic marker for the development of type I diabetes we investigated 66 subjects with first degree relatives of type I (47) and type II (9) diabetes as well as subjects with anamnestical data suggestive of diabetes. Patients were studied for glucose tolerance (oGTT) and IRI-response, ICSA (indirect fluorescence of living rat islet cell suspensions), ADCC (specific 51Cr-release of serum pretreated neonatal rat islets elicited by mononuclear cells) and HLA-antigens. 23 subjects revealed normal glucose tolerance, 17 impaired glucose tolerance and 26 had a prevoius abnormality. The incidence of ICSA varied between 46 and 53 per cent, that of positive ADCC between 22 and 56 per cent, both being highest in subjects with IGT. 87 per cent of all patients revealed diabetes associated HLA-antigens. We found no correlation of ICSA with glucose tolerance, IRI-response, ADCC and HLA-antigens. In conclusion it can be said that ICSA are present in a high percentage in patients with high diabetes risk but their predictive role as a marker for the manifestation must be elucidated in follow-up studies.

The frequency of islet cell surface antibodies in newly diagnosed diabetics from Ethiopia.

Forty-three newly diagnosed diabetic patients from Ethiopia were studied for the frequency of islet cell surface antibodies and other clinical features which are relevant to the aetiopathogenesis and classification of diabetes mellitus. In preliminary investigations of a small number of controls and noninsulin-dependent diabetics we found, as expected, no circulating antibodies. Four first-degree relatives of ICSA-positive sibs were negative, too. However, 3 out of 7 known insulin-treated diabetics displayed ICSA in the blood serum. In our study of newly diagnosed diabetics we found ICSA in 39% (17/43). Five patients who were assigned to the NIDDM subclass had no antibodies. 37 diabetics required insulin treatment after clinical diagnosis and 16 (43%) of these were ICSA-positive. There were no differences in the assessed clinical parameters between ICSA-positive and -negative patients. One ICSA-positive patient initially controlled with oral hypoglycaemic agents became insulin-dependent within our study period. Our observations in newly diagnosed diabetics from Ethiopia revealed a lower frequency of ICSA than in Caucasians, however, the results provide evidence for the occurrence of auto-immune phenomena in the aetiopathogenesis of diabetes mellitus in this ethnic group.

Monoclonal islet cell surface antibody dependent cellular cytotoxicity mediated by rat splenocytes with the RIN cell line as target.

A new method is described for testing monoclonal islet cell surface antibodies for their ability to mediate cellular immune effector mechanisms (ADCC). For the first time an IgM mediated cellular cytotoxicity is demonstrated. By using the RIN cell line as target the method was reproducible and easy to perform. The significance of such definition of monoclonal ICSA's to experimental diabetes research is discussed.

Forty-Year Observation of 280 Japanese Patients With Congenital Rubella Syndrome

There was a rubella epidemic in 1964–1965 in Okinawa, Japan. By 2004, 280 subjects were diagnosed with congenital rubella syndrome (CRS). All 280 patients followed over this 40-year period developed cataracts, sensory deafness, and/or heart disease. We measured islet cell surface antibody (ICSA), islet cell antibody (ICA), and anti-GAD65, IA-2, and insulin antibodies. Three (1.1%) (patients 1, 2, and 3) of these 280 CRS patients developed type 1 diabetes (positive autoantibodies to pancreatic β-cells). Patients 1 and 2 had diabetic ketoacidosis and type 1 diabetes. Patient 3 was diagnosed with diabetes at 18 years of age …

Prophylactic Insulin Treatment of Diabetes-prone BB/OK Rats by Application of a Sustained Release Insulin Implant

Normoglycemic diabetes-prone BB/OK rats aged 33, 45 or 75 days were subjected to prophylactic insulin treatment by means of a single subcutaneous application of a sustained release insulin implant. The single application of a sustained release insulin implant decreased the incidence of diabetes or delayed the onset of the disease in BB/OK rats of all treatment groups. Prophylactic insulin administration caused a transient hypoglycemic period accompanied by an inhibition of glucose stimulated insulin secretion and a decrease of the insulin content of Langerhans' islets as detectable in vitro . Compared to islets of normoglycemic controls pancreatic islets isolated from hypoglycemic BB/OK rats within 7-21 days after the insulin application at 45 days of age displayed a decreased susceptibility of the cells to complement-dependent cytotoxicity of the monoclonal islet cell surface antibody (ICSA) K14D10 but not to the cytotoxic effect of the ICSA M3aG8. The appearance of complement-dependent antibody-mediated cytotoxicity to islet cells and pancreatic exocrine cells in serum regarded as a sign of immune dysregulation in BB/OK rats seems not to be affected by insulin prophylaxis and was detectable during hypoglycemia as well as in the subsequent normoglycemic state. In conclusion, BB/OK rats of different age can be protected from diabetes by a single application of a sustained release insulin implant. Insulin and/or hypoglycemia seem to influence the expression of cell surface antigens, thus render the islets of Langerhans less vulnerable to immune cytolysis, whereas the appearance of humoral immunological abnormalites is not affected.

Islet cell surface antibodies (ICSA) do bind to human pancreas: computerised, quantitative determination of ICSA using both pre- and postembedding immunocolloidal techniques

Islet cell surface antibodies (ICSA) have been demonstrated significantly more often in serum of patients with IDDM and their relatives than in healthy controls, but some investigators have been unable to show binding to human islets. It has therefore been suggested that ICSA is an artefact. We have localised and quantified ICSA binding to different specimens, including human pancreas. ICSA-positive and ICSA-negative patients' serum, determined by a RIA-method, were incubated with ultrathin sections of rat insulinoma (RIN5AH) cells, stained with Goat-anti-human IgG conjugated with 10 nm gold particles. Sections were viewed in transmission electron microscopy (Mag. 30 000×) and image analyses was used to calculate immunolabelling. To test cell specificity we used (RIN5AH-cells, rat tumour cells producing growth hormone (GH 3), normal human pancreas, human insulinoma, and mice liver). Sections showed good morphology. ICSA-positive sera, with or without islet cell antibodies (ICA) gave always higher immunocolloidal labelling then ICSA-negative sera on RIN5AH sections. Thus, the colloidal gold technique could confirm the ICSA results determined with RIA. Immunolabelling was pronounced on normal human pancreas and human insulinoma cells, but none was found on GH3-cells or mice liver cells. ICSA is not an artefact but do exist and bind to human islet cells and therefore maybe can be used as a marker for IDDM immunity.

Autoantibodies in relation to residual insulin secretion in children with IDDM

To elucidate whether autoantibodies can be used to predict the intensity of autoimmune β-cell destruction, we determined both C-peptide and autoantibodies (islet cell antibodies (ICA), insulin autoantibodies (IAA), islet cell surface antibodies (ICSA) and antibodies to glutamic acid decarboxylase (GADA)), in 89 diabetic children and adolescents at diagnosis at the age of 1.2–16.6 years (mean ± S.D., 9.0 ± 4.5). Only 12 89 (14%) had no autoantibodies at diagnosis, while 2 patients (2%) had all 4 autoantibodies. There was a positive correlation between GADA and ICA ( P < 0.01). At diagnosis 70% of the patients had GADA, most common in patients above the age of 8 years at diagnosis ( P < 0.001), and with higher GAD-index in girls ( P < 0.05). ICA was detected in 63%, most common in the older age groups ( P = 0.04). ICSA seen in 22% of the patients as well as IAA (detected in 32%) were most common < 8 years of age ( P = 0.06, P = 0.08, respectively). Children with autoantibodies had similar C-peptide levels through the follow up period as children of the same sex and age without antibodies, except for patients with ICSA alone or in combination with other autoantibodies who tended to have higher C-peptide levels. We conclude that not even combinations of autoantibodies can be used to predict β-cell destruction in IDDM patients.

Islet cell surface antibodies are more common in patients and relatives in areas and during seasons with high incidence of insulin-dependent diabetes mellitus.

Although existence of islet cell antibodies (ICA) is regarded as secondary to beta cell death, islet cell surface antibodies (ICSA) might play a role in the disease process. We have collected information from nine European clinics to determine whether ICSA are more common in diabetic children or their relatives in geographical areas or time periods of high incidence of insulin-dependent diabetes mellitus (IDDM). In Finland and Sweden ("North group") with a high incidence of IDDM during childhood, 36% of the patients were positive or weakly positive for ICSA at diagnosis compared with 24% in France (p = 0.1), 11% in Berlin-Vienna (p < 0.01), and 14% in Italy (p < 0.01). This difference was seen in all age groups but was most pronounced in the youngest (0-4 y). This geographical difference was also seen among family members of whom 46% were positive or weakly positive in the North group, 25% in France (p < 0.001), 21% in Berlin-Vienna (p < 0.001), and 16% in Italy (p < 0.001). Of several analyzed antibodies (ICA, gastric parietal cell, thyroglobulin, and thyroid microsomal), only ICSA showed simultaneous positivity in all family members (r = 0.32, p < 0.01). ICSA were most common in family members of patients with short (< 8 d) duration of symptoms (p < 0.05) and showed a similar seasonality, both in patients and relatives, as the incidence of IDDM. We conclude that the geographical difference in incidence of childhood IDDM in Europe may be associated to similar geographical differences in occurrence of ICSA both in newly diagnosed diabetic children and in their relatives. Simultaneous existence of ICSA in both patients and family members and a similar seasonality for ICSA and incidence of IDDM suggest that ICSA may reflect an ongoing disease process.

A possible common cell surface autoantigen in islet beta-cells and thyroid follicular cells in patients with non-insulin dependent diabetes mellitus and chronic thyroiditis.

By an indirect immunofluorescence method with In-111 cells (hamster insulinoma cell line), circulating islet cell surface antibodies (ICSA) were detected in 7 (20%) out of 36 patients with non-insulin dependent diabetes mellitus (NIDDM), 9% of 68 chronic thyroiditis (CT) patients, or 16% of 19 NIDDM patients associated with CT, but not in 18 normal subjects. Sera from five out of nine ICSA-positive patients examined further also showed cell-surface immunofluorescence on TPC-1 cells (human thyroid papillary adenocarcinoma cell line), and prior absorption of the sera with In-111 cells abolished the immunofluorescence. The 64 kDa protein from In-111 cells or human thyroid follicular cells was immunoprecipitated with ICSA-positive sera. In one case of NIDDM associated with CT, 64 kDa protein was detected in both cells. The results indicate that some ICSA in NIDDM patients recognize the same or a very closely-related autoantigen(s) in both islet beta-cells and thyroid follicular cells, suggesting an explanation, at least in part, for the autoimmune mechanism(s) in clinical association of NIDDM and CT.