Islet-cell antibodies and insulin autoantibodies in association with common viral infections

A clinical case of insulin autoimmune syndrome with monoclonal gammopathy of uncertain significance; complexity in management

Insulin autoimmune syndrome (IAS) is a rare cause of spontaneous hypoglycaemia. We discuss a 91-year-old Caucasian lady who presented with syncope and episodic adrenergic and neuroglycopenic symptoms. Despite significantly elevated insulin, C-peptide, and proinsulin levels with the presence of anti-insulin antibodies, a pancreatic mass was not identified. Serum immunoelectrophoresis demonstrated monoclonal gammopathy of undetermined significance (MGUS). Treatment involved high-dose steroids, diazoxide, corn starch and acarbose, however the patient passed away four months later due to worsening co-morbidities. The management of IAS in the setting of MGUS is challenging.

Hirata's disease (insulin autoimmune syndrome) following envenomation by a common krait

Snakebite envenomation is known to cause local as well as systemic haematological, myotoxic and neurological effects. Adverse effects on the endocrine system following envenomation are rarely reported. Hirata's disease, also known as insulin autoimmune syndrome (IAS) is a rare disorder that causes hypoglycaemia due to excessive production of insulin autoantibodies. This report describes a rare case of IAS which developed in a snakebite victim following envenomation by a common krait and antivenom treatment. The patient was initially treated with dextrose and corticosteroids, although plasmapheresis was required to reduce the concentration of insulin antibodies and normalise the patient's glucose level. The patient then made an uneventful recovery without permanent sequelae. This report demonstrates the impacts of envenomation by a common krait on developing Hirata's disease and creates awareness among clinicians who treat snakebite envenomation.

Insulin autoimmune syndrome in an Argentine woman taking α-lipoic acid: A case report and review of the literature

Insulin autoimmune syndrome is an unusual cause of spontaneous hypoglycaemia in non-Asian populations. In the majority of cases, this syndrome appears a few weeks after the administration of drugs containing a sulfhydryl group. A strong association between this syndrome and HLA-DR4 has been shown. Only seven cases have been described in non-Asian patients. We report the first case of insulin autoimmune syndrome in an Argentine woman taking alfa-lipoic acid. She developed hypoglycaemic symptoms approximately 1 month after starting therapy. Blood sampling collected during an episode of symptomatic hypoglycaemia showed low blood glucose level (2.39 mmol/L), high level of serum insulin (1971.55 pmol/L), inappropriately high level of C-peptide (2.36 nmol/L) and high levels of insulin antibodies (274.78 IU/mL). HLA-DNA typing identified DRB1*04:03. Due to the widespread use of alfa-lipoic acid for its antioxidant properties, clinicians should be aware that it may trigger an autoimmune hypoglycaemia in people with a genetic predisposition.

Insulin autoimmune syndrome: from diagnosis to clinical management

Autoimmune forms of hypoglycemia are a rare cause of low blood sugar levels among Caucasians, and often go misdiagnosed, exposing patients to lengthy series of pointless, potentially harmful and expensive tests. There are two types of autoimmune hypoglycemia. One is insulin autoimmune syndrome (IAS), which is characterized by hyperinsulinemic hypoglycemia, elevated insulin autoantibody (IAA) titers, no prior exposure to exogenous insulin, and no of pathological abnormalities of the pancreatic islets. This condition is also known as "Hirata's disease". The other is type B insulin resistance syndrome (TBIRS), a rare autoimmune disorder resulting in a broad array of abnormalities in glucose homeostasis-from hypoglycemia to extremely insulin-resistant hyperglycemia-caused by the presence of insulin receptor autoantibodies (IRAbs). This review focuses on these two syndromes, describing their epidemiology, possible genetic background, clinical presentation, pathophysiology, diagnosis and treatment.

Insulin autoimmune syndrome (Hirata’s disease) in an Italian patient: a case report and review of the literature

We describe the case of a 54-year-old Caucasian Italian male experiencing episodes of hypoglycemia, occurring mainly after meals. He had never been exposed to insulin and was taking ramipril, flecainide and acetylsalicylic acid. An oral glucose tolerance test (OGTT) showed high blood glucose levels diagnostic for diabetes mellitus at 120 min and hypoglycemia with inappropriately high insulin levels at 240 min. The 72-h fasting test, abdominal computed tomography (CT) and positron emission tomography-CT were normal. Insulin autoantibodies were positive at high titers, prompting a diagnosis of insulin autoimmune syndrome (IAS). The patient was advised to take frequent, small meals and thus achieved a good control of his hypoglycemic symptoms. After 18 months of this dietary management, his insulin autoantibody levels decreased considerably but remained detectable. During an OGTT, his blood glucose levels at 120 min were now indicative of an impaired glucose tolerance rather than diabetes, and there was improvement in the glucose nadir. The patient had no other clinical or latent autoimmune diseases. Here we discuss the main features of IAS (also known as Hirata’s disease) and review the cases of IAS reported in Italy to date.

Environmental Risk Factors and Type 1 Diabetes: Past, Present, and Future

Type 1 diabetes is an autoimmune condition that results from the destruction of the insulin-producing beta cells of the pancreas. The excess morbidity and mortality resulting from its complications, coupled with its increasing incidence, emphasize the importance of better understanding the causes of this condition. Over the past several decades, a substantive amount of work has been done and, although many advances have occurred in identifying disease-susceptibility genes, there has been a lag in understanding the environmental triggers. Several putative environmental risk factors have been proposed, including infections, dietary factors, air pollution, vaccines, location of residence, family environment and stress. However, most of these factors have been inconclusive, thus supporting the need for further study into the causes of type 1 diabetes.

Class-switched anti-insulin antibodies originate from unconventional antigen presentation in multiple lymphoid sites

Unanue and colleagues show that activation of anti-insulin lymphocytes can occur at diverse anatomical sites in response to circulating insulin and may be driven by unconventional antigen presentation by germinal center B cells.

Autoantibodies to insulin are a harbinger of autoimmunity in type 1 diabetes in humans and in non-obese diabetic mice. To understand the genesis of these autoantibodies, we investigated the interactions of insulin-specific T and B lymphocytes using T cell and B cell receptor transgenic mice. We found spontaneous anti-insulin germinal center (GC) formation throughout lymphoid tissues with GC B cells binding insulin. Moreover, because of the nature of the insulin epitope recognized by the T cells, it was evident that GC B cells presented a broader repertoire of insulin epitopes. Such broader recognition was reproduced by activating naive B cells ex vivo with a combination of CD40 ligand and interleukin 4. Thus, insulin immunoreactivity extends beyond the pancreatic lymph node–islets of Langerhans axis and indicates that circulating insulin, despite its very low levels, can have an influence on diabetogenesis.

Fulminant type 1 diabetes mellitus associated with a reactivation of Epstein-Barr virus that developed in the course of chemotherapy of multiple myeloma

A 70‐year‐old woman who was diagnosed with multiple myeloma underwent chemotherapy. Three months after beginning chemotherapy, she was readmitted to the hospital because of fever and hepatopathy. Her elevated Epstein–Barr virus (EBV) antibody levels showed that the hepatopathy was caused by reactivation of EBV. On the 18th hospital day, the levels of fasting plasma glucose (FPG; 451 mg/dL) and pancreatic enzymes were suddenly elevated. Elevation of HbA_1c level (6.4%) was slight, as compared with that of the FPG level. Arterial blood gas analysis showed metabolic acidosis and diabetic ketoacidosis was suspected. The serum C‐peptide level was below the detectable limit both before and after glucagon load, thereby suggesting an insulin‐dependent state. These features were identical to the features for fulminant type 1 diabetes mellitus. The levels of EBV anti‐viral capsid antigen immunoglobulin M decreased, and the clinical course was identical to that associated with reactivation of EBV infection. (J Diabetes Invest, doi: 10.1111/j.2040.1124.2010.00061.x, 2010)

Type 1 diabetes mellitus: etiology, presentation, and management

This article reviews our current understanding of the etiology, presentation, and management of type 1 diabetes. The discussion includes a review of the natural history of diabetes, the complex relationship between genetic and environmental risk for type 1 diabetes, and current methods for prediction of type 1 diabetes. The article also reviews the current management of children who have new-onset type 1 diabetes, age-appropriate management goals, and diabetes complications. Finally, the article discusses the future of diabetes screening programs and the progress toward the ultimate goal of curing type 1 diabetes.

Insulin autoantibody isotypes during the prediabetic process in young children with increased genetic risk of type 1 diabetes

This work aimed to assess the maturation of the humoral immune response to insulin in preclinical type 1 diabetes by observing the emergence of various isotypes of insulin autoantibodies (IAA) in children with HLA-DQB1-conferred disease susceptibility. The series was derived from the Finnish Type 1 Diabetes Prediction and Prevention Study and comprised 15 IAA-positive children who presented with type 1 diabetes during prospective observation (progressors) and 30 children who remained nondiabetic (nonprogressors). An isotype-specific radiobinding assay was used to determine isotype-specific IAA (IgG1-4 and IgA) from samples obtained with an interval of 3-12 mo. The progressors had IAA of subclass IgG3 in their first IAA-positive sample more often than did the nonprogressors (13 of 15 versus 12 of 30; p = 0.003). Nine progressors had a dominant IgG1-IAA response initially, and six had a dominant IgG3-IAA response. The corresponding distribution among the nonprogressors was that 20 had a dominant IgG1-IAA response, none had an IgG3-IAA response, and three had a dominant response other than IgG1- or IgG3-IAA (chi(2)(df = 2) = 12.02; p = 0.002). The progressors had higher integrated levels (area under the curve) of IgG1-IAA (p = 0.05) and IgG3-IAA (p = 0.002). Nine progressors had a dominant integrated IgG1-IAA response and six had a dominant IgG3-IAA response over the observation period, whereas 22 nonprogressors had a dominant IgG1-IAA response, six had a dominant IgG2-IAA response, and one an IgG3-IAA response (chi(2)(df = 2) = 11.23; p = 0.004). Genetically susceptible young children who progress rapidly to clinical type 1 diabetes are characterized by strong IgG1 and IgG3 responses to insulin, whereas a weak or absent IgG3 response is associated with relative protection from disease.

Antigen-specific responses in autoimmunity and tolerance

Autoantibodies to the hormone insulin arise spontaneously in the insulin autoimmune syndrome and in the prodrome of type I diabetes. Further, administration of insulin to individuals without autoimmune disease routinely results in antibodies that bind autologous hormone. These observations suggest that physiological levels of hormones, such as insulin, are below critical thresholds for signaling tolerance induction, a state termed clonal ignorance. In contrast, studies from our laboratory on the genetic origins and structure of V genes used by insulin antibodies suggest that the anti-insulin repertoire is tightly regulated. We have shown that B cells in mice harboring an insulin antibody transgene are functionally silenced. These findings verify that tolerance is active for small molecules, even when they are present at low concentrations. Despite active tolerance, insulin antibodies are sustained in the repertoire of normal animals by several mechanisms, including activation by TI antigen signals, unique display of conformational epitopes, and the recruitment of B cells previously selected by responses to other antigens. This essay reviews our current understanding of escape pathways for anti-insulin B cells.

Antibody screening in a population of children

The first large-scale (secondary) intervention trials have been initiated in first-degree family members of patients with insulin-dependent diabetes mellitus (IDDM). Within a few years, data from these studies may suggest that intervention is possible, thereby opening similar approaches in the general population. However, before large-scale intervention studies can be initiated, several problems need to be solved. One of these problems is the lack of knowledge on the natural course of beta-cell autoimmunity. This review analyses this and other issues related to population-based prediction for IDDM. At present, no long-term follow-up studies are available in large-sized populations, but data show that prediction in the general population is both technically feasible and likely to have sufficient power to be useful in prevention trials. More data need to be generated, not only to determine which markers are most likely to give good prediction but also to obtain knowledge on the natural course, psychosocial impact and cost-effectiveness of screening.

Insulin antibodies and hypoglycemia in diabetic patients. Can a quantitative analysis of antibody binding predict the risk of hypoglycemia?

We report a noninsulin-dependent diabetes mellitus (NIDDM) patient with spontaneous, severe hypoglycemic reactions and the presence of insulin antibodies. He had a remote antecedent history of beef-pork insulin therapy as well as exposure to hydralazine. Detailed insulin binding kinetic studies were performed in this patient as well as in six other insulin-treated diabetic patients with anti-insulin antibodies (three with and three without an obvious cause of hypoglycemia). Sera from the current patient and five of the six other diabetic patients (one NIDDM, four IDDM) revealed two types of binding sites: high-affinity with low capacity (Kd, 0.4-12.4 x 10(-9) mol/L; binding capacity, 0.6-659 mU/L) and low-affinity with high capacity (Kd, 0.3 to 35.7 x 10(-7) mol/L; binding capacity; 202-113,680 mU/L). One NIDDM patient had only high-affinity antibodies (Kd, 22.9 x 10(-9) mol/L; binding capacity of 78 mU/L). Type of diabetes mellitus, insulin antibody titers or their binding capacities, insulin levels (total, bound, or free), and bioavailable insulin were not related to hypoglycemic reactions. Two calculated values by the method described tended to discriminate patients with and without hypoglycemia. The calculated amount of low-affinity antibody bound insulin ranged from 69.4-2090 mU/L vs < 4-70.6 mU/L in patients with and without hypoglycemia, respectively. The best discrimination was afford by the percent saturation of low-affinity binding sites; values were clearly higher in the patients with hypoglycemia (2.5-34.4%) than in those without hypoglycemia (not detectable, 0.06, 0.15%). Consideration of the possible drug-associated insulin antibody formation in insulin-treated diabetics and the novel quantitative analysis of the antibody binding kinetics should prove helpful in evaluating patients with high insulin antibody titers and assessing the risk of hypoglycemia.

Islet cell autoimmunity and progression to insulin-dependent diabetes mellitus in genetically high- and low-risk siblings of diabetic children. The Childhood Diabetes in Finland (DiMe) Study Group

Insulin-dependent diabetes mellitus (IDDM) risk was evaluated in 765 siblings based on prospective observation of islet cell antibodies (ICAs) and insulin autoantibodies (IAAs) as a function of the degree of HLA identity to the proband and HLA-DR alleles. Twenty-eight (3.7%) siblings progressed to IDDM over a median observation period of 5.8 years. ICAs had higher sensitivity than IAAS (100% vs. 33% , P < 0.001), whereas persistent ICA positivity and double ICA/IAA positivity defined the highest actuarial risk (47% and 70%). Diabetes manifested after a mean of 3.2 years from the detection of ICAs in those siblings who were initially ICA negative and, importantly, the risk was equal to that of the siblings constantly positive from the first sample obtained. Although the combination of HLA identity and ICAs at or above 80 Juvenile Diabetes Foundation units carried the highest positive predictive value (77%), the high-risk HLA markers were insufficient to predispose siblings with low ICA levels to IDDM and low-risk HLA markers did not provide complete protection against high ICA levels and from subsequent IDDM. These results emphasize ICAs as the primary tool for risk evaluation in siblings followed by restricted HLA subtyping to reduce the population to be subjected to clinical intervention trials.

Two short autoepitopes on the nuclear dot antigen are similar to epitopes encoded by the Epstein-Barr virus

To understand the relationship between antibodies present in patients with anti-nuclear dot (ND) autoimmune disease and the proteins they recognize, epitopes that react with the autoantibodies were mapped. A panel of fusion proteins containing different portions of the ND protein were overproduced in Escherichia coli. Immunoblot analysis with anti-ND antibodies revealed that most (10 of 12) sera recognize two major autoepitopes that are each a maximum of 8 amino acids long. The other two sera recognize one of the two epitopes. In addition to the short linear autoepitopes, a conformational epitope appears to be present on the ND antigen. Each of the two linear epitope sequences shares sequence similarities with those of several viral proteins found in the databases. Furthermore, two fusion proteins containing short Epstein-Barr virus (EBV) protein sequences that are similar to the ND epitopes were recognized by the human autoimmune sera, indicating that the autoepitopes are present in EBV protein sequences. Our results are consistent with the hypothesis that ND autoimmune disease might be associated with EBV infections.

A search for candidate viruses in type 1 diabetic pancreas using the polymerase chain reaction

In order to investigate a possible viral aetiology for Type 1 diabetes the polymerase chain reaction (PCR) technique was used. Pancreatic tissue from Type 1 diabetic subjects was examined for the presence of a panel of common viruses. Primers specific for mumps, measles, cytomegalovirus, and Epstein Barr virus, as well as primers located in a highly conserved region of the enterovirus genome which are capable of detecting all of the following family members: Coxsackie B, echovirus, polio, mengovirus, and encephalomyocarditis virus were used to screen 18 Type 1 diabetic subjects of whom 3 had proven insulitis, 12 Type 2 diabetic subjects and 18 non-diabetic controls. Epstein Barr virus was detected in two Type 1 (13%), two Type 2 (22%), and three of the normal nondiabetic pancreases (20%), and the DNA sequences confirmed by direct sequencing. Cytomegalovirus was detected in one of the normal pancreases only and no evidence of any of the other viruses was found. It is concluded that the Type 1 diabetic pancreatic samples studied did not show persistence of infection with any of the above viruses. Non-persistent acute infection of the pancreas by the above viruses cannot be excluded in the aetiology of Type 1 diabetes from this study.

An unusual case of recurrent hypoglycaemia: 10-year follow up of a child with insulin auto-immunity

We report the case of a child with hypoglycaemia due to insulin auto-immunity. Insulin auto-immunity is the third most frequent cause of hypoglycaemia in Japan where the first cases were described. The child has been followed for the past 10 years with recurrence of hypoglycaemic symptoms and high titres of insulin antibodies.

Polymorphism of insulin antibodies in six patients with insulin-immune hypoglycaemic syndrome

Insulin antibodies in six patients with immune hypoglycaemic syndrome were studied. The antibodies displayed a higher affinity for bovine insulin in two patients, were specific for human insulin in one patient and non-species specific in the other three patients. The predominant IgG subclass of the insulin antibodies was IgG4 in two patients, IgG3 in two and IgG1 in two. In one of these, the other three subclasses were also detectable. Insulin autoantibodies of four patients were homogeneous with regard to light chains (kappa), and those of the other two contained both kappa and gamma light chains. Analysis of insulin immune complex size by fast protein liquid chromatography was possible in three patients and demonstrated immune complexes with elution profile close to that of IgG, although not exactly superimposable to the one obtained with a mouse monoclonal insulin antibody. In two patients, avidity was too low to permit chromatography of the immune complexes, and, moreover, in these two cases insulin antibodies were of the IgG3 isotype and spontaneously formed aggregates independently of insulin binding. We conclude that insulin antibodies of the insulin immune syndrome are polymorphic but different from those generated by insulin therapy.

Does exposure to rubella virus generate endocrine autoimmunity?

Rubella virus is a possible environmental agent which may be involved in triggering autoimmunity to pancreatic islet cells, leading to Type 1 diabetes. Autoantibody responses were determined in 239 10-year-old girls who received live attenuated rubella vaccine, of whom 61 (26%) had no pre-existing rubella immunity. Islet cell antibodies (ICA greater than 5 Juvenile Diabetes Foundation (JDF) units) were present in seven (2.9%) girls before vaccination, and they appeared in three more 6 weeks after vaccination (4.2%). However, the ICA levels were low in all cases and of the three girls who developed ICA greater than 5 JDF units 6 weeks post-vaccination, none had detectable ICA 18 months later. IgG-insulin autoantibodies were present in 17 (7.1%) girls before vaccination, and their prevalence decreased after vaccination (5.4%). Thyroid antibodies (thyroglobulin and microsomal) were present in 2% and 1%, respectively, of the girls before vaccination and none appeared afterwards. Thus, rubella vaccination did not elicit widespread endocrine autoantibody production and viral triggering of endocrine autoimmunity in susceptible subjects remains an open question.

Natural history of incidental hyperglycemia and glycosuria of childhood

We prospectively followed 29 children and adolescents over a 1- to 8-year period who were referred for evaluation of hyperglycemia (in the absence of diabetes) or glycosuria found on routine screening or during acute illness. On initial examination, four subjects had islet cell autoantibodies, 4 of 22 had an abnormal intravenous glucose tolerance test result, 6 of 22 had low first-phase insulin release on intravenous glucose tolerance testing, and 10 of 20 had impaired glucose tolerance on oral glucose tolerance testing. On follow-up, insulin-dependent diabetes had developed in two of the four subjects with islet cell autoantibodies. The other two subjects with islet cell antibodies have had persistently abnormal glucose tolerance on both oral and intravenous glucose tolerance testing and have low first-phase insulin responses. Diabetes has developed in none of 25 subjects without islet cell antibodies, although two have persistently abnormal glucose tolerance or insulinopenia. All five subjects with islet cell antibodies or human leukocyte antigen DR3/DR4 with initial impaired glucose tolerance have either acquired diabetes or have abnormal glucose tolerance. In contrast, only one of five subjects with initial impaired glucose tolerance but lacking these markers has persistent glucose intolerance. We conclude that in the absence of islet cell antibodies or human leukocyte antigen DR3/DR4 heterozygosity, incidental hyperglycemia or glycosuria is unlikely to be associated with progression or diabetes.

Autoimmune insulin syndrome

Initially described in Japan, the autoimmune insulin syndrome is caused by the presence of anti-insulin antibodies in patients who have never received insulin. This syndrome accounts for spontaneous or reactive hypoglycaemia with very high levels of total immuno-reactive insulin. Discordance between the levels of immunoreactive insulin and C peptide indicate the possible presence of anti-insulin antibodies; this can avoid an incorrect diagnosis of insulinoma. These autoimmune hypoglycaemias often present a difficult diagnostic problem in distinguishing them from factitious hypoglycaemia. The course of the autoimmune insulin syndrome is usually favourable, with a spontaneous rapid diminution of the levels of anti-insulin antibodies. The reasons for the appearance of anti-insulin antibodies and the exact mechanisms of the hypoglycaemia remain uncertain. However, the frequent association of the autoimmune insulin syndrome with certain autoimmune diseases suggest a common immune dysfunction. Drugs containing a sulphydryl group have been implicated in the aetiology of this syndrome.

Factors affecting the insulin autoantibody ELISA

IgG antibodies to insulin are present in insulin-treated patients and are detected in the prodrome of untreated type I diabetes. Sporadic reports of autoantibodies to insulin suggest that they are also present in other disorders. To establish the incidence of insulin autoantibodies in other endocrine and autoimmune diseases an ELISA was used to examine sera from 529 subjects with no prior insulin therapy. These untreated patients included: normal controls (adults and children), newly-diagnosed type I diabetes, first-degree relatives of diabetics, type II diabetes, Graves' hyperthyroidism, and systemic lupus erythematosus. As a positive control group, 280 insulin-treated patients were studied. Measurement of IgG antibodies by direct binding to insulin coated plates was complicated by differences between adult and pediatric populations and by overlap of binding between treated and untreated subjects. Competitive inhibition with excess soluble human insulin overcame these problems and permitted identification of insulin specific binding. Using this approach insulin antibodies were most frequent in insulin-treated diabetics (98%) and in type I diabetics (37%) prior to treatment. The absolute numbers of subjects with insulin autoantibody in the other groups differed depending upon whether a cut-off for binding (mean + 2SD of controls) or for insulin inhibition of binding (45%) was used. Regardless of the criteria used there were subjects (2-24%) in all groups tested with circulating insulin-specific IgG autoantibody detected by ELISA. These low level antibodies detected in solid phase assays may be part of the normal immune repertoire.

Immunological aspects of diabetes mellitus: prospects for pharmacological modification

It is now well known that insulin-dependent diabetes is a chronic progressive autoimmune disease. The prolonged prediabetic phase of progressive beta-cell dysfunction is associated with immunological abnormalities. A prediabetic period is suggested by the appearance of islet cell antibodies, anti-insulin antibodies, and anti-insulin receptor antibodies. The existence of activated T lymphocytes and abnormal T cell subsets are also other markers. There is still no concensus about the use of the immunosuppression superimposed upon conventional insulin therapy in early diagnosed IDDM and the follow-up of the relatives of IDDM patients who share the genetic predisposition and serological markers for the risk of future onset of IDDM. Treatment in the prodromal period cannot be justified because a link between the disease and early markers such as ICA has not been established with certainty (Diabetes Research Program NIH, 1983). Many immunopharmacological manipulations were reported to be effective in animal models. However, most of them are not readily applied to human subjects. Moreover, IDDM patients are now believed to be heterogeneous, with a complex genetic background. HLA-DR, and more recently DQ, are closely related to the genetic predisposition to IDDM but those genes are not themselves diabetogenic. The contribution of autoimmunity does not appear to be uniform, and in some cases, the contribution of virus is considered more important. There is a lack of a marker for the future onset of IDDM. ICA and ICSA were found after mumps infection, but the existence of those autoantibodies and even the co-existence of HLA-DR3 do not always indicate the future trend to insulin dependency. More precise markers will be disclosed through the biochemical analysis of the target antigens on pancreatic beta-cell for islet antibodies and effector T cells. Much safer and more effective immunopharmacological treatment will be developed through animal experimentation using rat and mouse models. The recent development and interest in this field will further facilitate the attainment of the goal for the complete prevention of IDDM.

Monoclonal autoantibodies derived from multiple sclerosis patients and control persons and their reactivities with antigens of the central nervous system

Peripheral blood B lymphocytes of multiple sclerosis (MS) patients and control persons were transformed with Epstein-Barr virus. Antibody production of transformed cells against isolated human myelin was investigated by enzyme-linked immunosorbent assay (ELISA). Cells producing reactive antibodies were cloned and propagated to produce monoclonal antibodies (mAbs). These mAbs did also react with acetone fixed frozen sections of normal human white matter, as determined by indirect immunofluorescence staining. Some of the mAbs derived from MS patients and a control person with a central nervous system cyst agglutinated liposomes made from lipids of a chloroform/methanol extract of human myelin, whereas mAbs derived from four glioma patients were negative in these tests. The reactive antibodies were investigated further using agglutination tests with liposomes made from pure auxiliary lipids (cholesterol and lecithin) or containing in addition either galactocerebroside, sulfatide or a mixture of bovine brain gangliosides. The great majority of myelin liposome agglutinating antibodies reacted with all types of liposomes, including those made from pure auxiliary lipids. Investigations by ELISA suggest that phospholipids are the reactive components, at least for some of these mAbs. Some antibodies reacted with liposomes containing galactocerebroside or sulfatide, others only with sulfatide containing liposomes. Antibodies showing these specificities were only obtained from MS patients.

Insulin autoantibodies are associated with islet cell antibodies; their relation to insulin antibodies and B-cell function in diabetic children

Blood was drawn from 74 children, 3-16 years old, at diagnosis of Type 1 (insulin-dependent) diabetes and before the first insulin injection. Insulin autoantibodies were detected with a polyethylen-glycol-method in 27/74 (36.4%) and with an immuno-electrophoretic method in 6/74 (8.1%). Islet cell cytoplasmic antibodies detected by indirect immuno-fluorescence were found in 49/74 patients (66.2%), who included as many as 23 of the 27 patients with insulin autoantibodies determined with the polyethylen-glycol-method (p less than 0.01). The proportion of insulin autoantibody-positive patients who developed insulin antibodies during the first 9 months of insulin treatment was not significantly greater (51.8%) than that of insulin autoantibody-negative patients (44.6%), but patients with both islet cell antibodies and insulin autoantibodies at diagnosis produced more insulin antibodies during the first 9 months (p less than 0.05). There was no difference in fasting or meal stimulated serum C-peptide after 3, 9 or 18 months as related to occurrence of insulin autoantibodies and/or islet cell antibodies. The correlation between insulin autoantibodies and islet cell antibodies indicates that both types of autoantibodies reflect the same immunological process, although the lack of correlation to C-peptide may indicate that they play a minor causal role. In addition, the results show that patients with an active autoimmune process evidently tend to produce more insulin antibodies during the first months of insulin treatment, but the islet cell antibodies and insulin autoantibodies-positive patients had at least as good residual B-cell function as patients without autoantibodies at diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between serum insulin autoantibodies, islet cell antibodies and Coxsackie-B4 and mumps virus-specific antibodies at the clinical manifestation of type 1 (insulin-dependent) diabetes

In order to elucidate the possible relationship between insulin autoantibodies (IAA), conventional (ICA-IgG) and complement-fixing (CF-ICA) islet cell antibodies and Coxsackie-B4 and mumps virus-specific antibodies (IgG, IgM and IgA classes), we studied 194 children and adolescents with newly diagnosed Type 1 (insulin-dependent) diabetes. Sixty-one (31.4%) of the subjects were IAA-positive at diagnosis and 73.8% (45/61) of these also had ICA-IgG compared to 51.1% (68/113, p less than 0.01) of IAA-negative children. CF-ICA showed no significant association with IAA. The levels of IAA were significantly higher in the patients with ICA-IgG compared to those without [5.9 +/- 1.6% (SEM) vs 2.5 +/- 0.3%, p less than 0.01]. The patients positive for IAA were younger at diagnosis than the IAA-negative ones; (7.1 +/- 0.5 vs 9.3 +/- 0.3 years, p less than 0.001) and this was also true for ICA-IgG-positive children (8.1 +/- 0.4 vs 9.4 +/- 0.5 years, p less than 0.05) in comparison to ICA-IgG-negative subjects. No significant associations were found between IAA or ICA on the one hand and a positive family history of Type 1 diabetes or metabolic derangements at diagnosis on the other. Subjects negative for ICA were more frequently positive for mumps virus specific IgG antibodies than the ICA-positive patients (50/80 vs 53/111, p less than 0.05), and Coxsackie-B4 virus-specific IgA antibodies were more common in the CF-ICA-negative than the CF-ICA-positive children (53/111 vs 29/80, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

On the relationship between islet cell antibodies and insulin autoantibodies in patients at risk from insulin dependent diabetes

The frequencies of islet cell antibodies (ICA) and insulin autoantibodies (IAA) were studied in three clinically well defined groups, using an aprotinin sensitised indirect immunofluorescence assay for ICA and a direct binding solid ELISA for IAA, and the association of these two serological markers for insulin dependent diabetes analysed. Frequency of ICA was 10.7% in siblings of diabetics, 15.5% in discordant identical twins and 65.9% in newly diagnosed diabetic patients. Frequency of IAA was 7.1% in siblings, 46.7% in discordant twins and 38.6% in newly diagnosed diabetic patients. No correlation was demonstrated between the two autoantibodies in the siblings. In the newly diagnosed diabetic patients there were sera positive or negative for both, but 22 (50%) of the sera showed dissociation between the two antibodies. The studies of twins showed that IAA and ICA fluctuated independently with time, and demonstrate the inappropriateness of seeking such an association in cross-sectional surveys. An association could not be demonstrated in this group even if data from multiple samples taken at different points in time were pooled, scoring an individual as positive if at any time their sera had been positive for the corresponding antibody. Thus our data showed no correlation between ICA and IAA in any of the groups studied.