G.J. Bruining

Antibodies to a 64,000 Mr human islet cell antigen precede the clinical onset of insulin-dependent diabetes.

Antibodies in sera from newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients are directed to a human islet cell protein of relative molecular mass (Mr) 64,000. Since IDDM seems to develop after a prodromal period of beta-cell autoimmunity, this study has examined whether 64,000 Mr antibodies could be detected in 14 individuals who subsequently developed IDDM and five first degree relatives who have indications of altered beta-cell function. Sera were screened by immunoprecipitation on total detergent lysates of human islets and positive sera retested on membrane protein preparations. Antibodies to the 64,000 Mr membrane protein were consistently detected in 11/14 IDDM patients, and in all 5 first degree relatives. 10 IDDM patients were already positive in the first samples, obtained 4-91 mo before the clinical onset of IDDM, whereas 1 patient progressed to a high 64,000 Mr immunoreactivity, at a time where a commencement of a decline in beta-cell function was detected. 64,000 Mr antibodies were detected before islet cell cytoplasmic antibodies (ICCA) in two patients. In the control groups of 21 healthy individuals, 36 patients with diseases of the thyroid and 5 SLE patients, the 64,000 Mr antibodies were detected in only one individual, who was a healthy sibling to an IDDM patient. These results suggest that antibodies against the Mr 64,000 human islet protein are an early marker of beta-cell autoimmunity and may be useful to predict a later development of IDDM.

Continuous subcutaneous insulin infusion (CSII) versus conventional injection therapy in newly diagnosed diabetic children: two-year follow-up of a randomized, prospective trial.

The effect of continuous subcutaneous insulin infusion (CSII), begun at diagnosis, on blood glucose control and endogenous insulin production was studied in a group of consecutively referred newly diagnosed diabetic children. In a random order, 15 children started CSII (age 9.5 ± 4.2 (±SD) years) and 15 conventional injection therapy (age 7.0 ± 3.6 years). For 2 years HbA1, and urinary C‐peptide were measured monthly, C‐peptide responses to glucagon 6‐monthly, and insulin antibodies every 3 months. None of the patients requested change of therapy during the study period, but at 28 months 1 adolescent girl changed to injection therapy from CSII. Severe hypoglycaemia was observed once in each group, but ketoacidosis only once, in the injection therapy group. From 2 months after diagnosis onwards the CSII group had significantly lower HbA1, levels. Urinary and plasma C‐peptide levels did not differ between the two groups and similar insulin doses were used throughout the study. At the end of the 2 years of therapy, the CSII group had significantly lower insulin antibody levels. The observations suggest that CSII is well accepted in newly diagnosed children and improves metabolic control, but does not prolong endogenous insulin production.

HLA and GM in insulin-dependent diabetes in the Netherlands: report on a combined multiplex family and population study.

This report deals with the genetic factors involved in insulin-dependent diabetes mellitus (IDD) in The Netherlands. Twenty-two Dutch multiplex families with IDD were typed for HLA-A, -B, -C, and -DR antigens, for BF, C2, C4, and GLO polymorphisms, as well as for GM allotypes of immunoglobulins. In addition, 53 unrelated IDD children and 31 unrelated patients with adult onset IDD were typed for HLA-A, -B, -C, and -DR antigens. A significant heterogeneity for the frequency of HLA-DR4 related to age of onset was observed. A significant deviation of the Hardy-Weinberg equilibrium was observed for the HLA-DR locus with an excess in patients of heterozygotes HLA-DR3, -DR4.HLA-B8, and HLA-B15 were not only secondary associated, but constituted with HLA-DR3 and -DR4, respectively, a haplotype in association with IDD. Nonrandom segregation of HLA-haplotypes was observed in multiplex families exemplified by an excess of HLA-identical affected sibpairs . Cross- overs between HLA-DR and GLO identified the HLA-DR segment as mainly involved in the association with IDD. Three diabetic haplotypes were confirmed to occur frequently among affected sibs: (a) A1, B8, BFS, C2.1, C4AQO , C4B1 ,DR3, GLO2 ; (b) Aw30, Cw5 ,B18,BFF1,C2.1, C4A3 , C4BQO ,DR3, GLO2 ; (c) A2,Cw3, B15,BFS, C2.1, C4A3 , C4B3 , DR4,GLO1. The segregation of GM allotypes to affected sibpairs was not significantly different from random segregation. The main conclusions from this study are that significant heterogeneity for age of onset exists and that the data are not compatible with simple genetic models including dominant, recessive, and intermediate models of inheritance. The data do require more complex models, involving two different HLA-linked (sets of) susceptibility genes.

Continuous Subcutaneous Insulin Infusion in Children

Insulin‐dependent diabetes mellitus usually presents in childhood. Since it is generally accepted that persisting metabolic derangements contribute to the development of microand macrovascular complications, a primary aim of the management of children with diabetes is to achieve near normalization of metabolism. In adults continuous subcutaneous insulin infusion (CSII) has been used to optimize control. Despite a reluctance amongst paediatricians to use CSII in children, several studies with pumps have been performed in adolescents. The results of these studies are contradictory with respect to acceptability and achieved metabolic control. Thus, some authors report a near normilization of blood glucose concentrations, whereas others only find a temporary improvement. Patient selection seems to account for many of these differences. This suggests that methods ought to be developed to predict success or failure of CSII in a particular adolescent patient. For diabetic toddlers with their age‐specific problems CSII may be a therapy of choice. So far, good acceptability and improved metabolic control are reported in this group. More studies are needed to confirm this. It is important that the diabetic clinic as well as the patient is organized to a high standard before starting CSII. Home blood glucose measurements, education, and a 24‐h telephone service are essential factors for the management of diabetic children, treated conventionally or with CSII.

Overnight metabolic profiles in very young insulin-dependent diabetic children

The magnitude of the disturbance of metabolic control in diabetes mellitus in very young children has been recognised, but seldom studied. Limitations to studies are set by the difficulty of obtaining control data and until recently the lack of alternative therapies. Recently “mini” pumps for continuous subcutaneous insulin delivery have become available and may offer an alternative therapeutic possibility. The present investigation has been undertaken to collect overnight metabolic data of very young diabetic children (<6 years) controlled by standard injection therapy. During one admission to hospital frequent blood samples were collected for free insulin, glucose, alanine, lactate, glycerol and 3-hydroxybutyrate determinations. In all children (n=9) the profiles showed a steep rise in glucose from 04.30h (6.2±1.3 mmol/l) to 09.30h (17.8±2.4 mmol/l) (the so-called “dawn-phenomenon”). The nature of the changes in the intermediary metabolites suggested that rise in blood glucose was caused by insufficient insulin. We have attempted to explore the time relationship between the overnight drop in free insulin levels and the rises in blood glucose by a distribution-free statistical analysis, correlating successive changes in time between the two profiles. The analysis suggested a delay of 2–6 h between free insulin levels and their effects.In conclusion: a clear “dawn phenomenon” is seen in very young diabetic children, and contributes to their poor glycaemic control. More stable and higher insulin concentrations in the early morning, obtained perhaps by continuous subcutaneous insulin infusion, might ameliorate the overall glycaemic control in the very young diabetic child.

Confirmation of High Incidence of Type 1 (Insulin-dependent) Diabetes Mellitus in Moroccan Children in The Netherlands

The incidence of Type 1 (insulin‐dependent) diabetes mellitus among Moroccan children aged (0–19 years) in The Netherlands was determined. Point of reference was the data derived from the second nationwide incidence study on Type 1 diabetes among children under 20 years of age. In that study the incidence among Dutch children was 13.2 100u2009000−1 year−1. To scrutinize the data and to obtain more information a questionnaire was sent in 1993 to all specialists who had reported that they had diagnosed a patient with Type 1 diabetes during the years 1988–1990 whose parents originated from Morocco, Turkey or other foreign countries. The questionnaire requested information on origin and migration of child and parents. The response to the questionnaire was 86u2009% for the Moroccan children, 75u2009% for the Turkish children and 100u2009% for the children from other countries. In only one case a wrong country had been recorded. None of the patients had been in The Netherlands for less than 6 months before the diagnosis. The incidence for Moroccan children was 20.0 (95u2009% CI 14.6–26.9) and for Turkish children 4.5 (95u2009% CI 2.2–8.0) 100u2009000−1 year−1. It is concluded that the incidence of Type 1 diabetes in Moroccan children (0–19 years) is 1.5 times higher than in Dutch children and 4.5 times higher than in Turkish children. ©u20091997 by John Wiley & Sons, Ltd.

Insulin antibodies in diabetic children before treatment: a marker for islet B-cell destruction?

Insulin antibodies were measured in the sera of 28 newly diagnosed diabetic children (age 8.0 ± 4.0 (±SD) years) prior to insulin therapy and after 3, 6, 9, and 12 months. The levels at diagnosis and after 12 months were compared to endogenous insulin production at onset and after 12 to 14 months. Endogenous insulin production was evaluated through the measurement of 24‐h urinary C‐peptide excretion, fasting plasma C‐peptide levels and plasma C‐peptide levels after glucagon stimulation. Insulin antibodies were detected in 29 % of the patients (8 out of 28). In all but one patient antibodies binding porcine and human insulin were detected. No relationship was found between the presence of antibodies binding human or porcine insulin at diagnosis and age. After 1 year 27 out of 28 patients presented insulin antibodies. No relationship was found between the presence of insulin antibodies before therapy and 1 year after therapy. Insulin antibodies prior to diagnosis showed no relationship with the urinary C‐peptide excretion at diagnosis (with antibodies 67 ± 27 %, without antibodies 76 ± 11 %). However, after 1 year significantly lower urinary C‐peptide excretions were found in patients with insulin antibodies prior to therapy (with antibodies, 17 ± 7 %, without antibodies, 31 ± 5 %, p<0.02). Peak plasma C‐peptide levels after 1 year were possibly lower in patients with insulin antibodies before treatment (with antibodies 0.17 ± 0.06 nmol/l, without antibodies 0.26 ± 0.04 nmol/l, p<0.1). Fasting C‐peptide levels did not differ significantly between the two groups after 1 year of therapy (with antibodies 0.11 ± 0.03 nmol/l, without antibodies 0.14 ± 0.02 nmol/l). Thus, insulin auto‐antibodies may be a marker for islet B‐cell destruction in Type 1 diabetes.

Urinary C-peptide: A useful tool for evaluating the endogenous insulin reserve in cohort and longitudinal studies of diabetes in childhood

Increasing research into the remission phase of type I diabetes mellitus stresses the importance of a non-traumatic and reliable method for the evaluation of endogenous insulin production. We compared 24-h urinary C-peptide excretion (UCE) with plasma C-peptide values before and after stimulation with 1 mg glucagon in 24 type I diabetic children. Fasting plasma C-peptide values and stimulated plasma C-peptide values showed a linear correlation with 24 h UCE. Mean plasma C-peptide levels correlated inversely with the exogenous insulin dose. A slightly better correlation was found between the exogenous insulin dose and 24 h UCE. Control data of 24 h UCE were obtained from healthy siblings. A linear correlation with age was found up to 10 years of age above which UCE values seem to reach a plateau. This effect of age, as well as the frequency of sampling was taken into account in the derivation of 95% reference intervals for UCE. The measurement of 24 h UCE appears to be a useful parameter to assess endogenous insulin production in diabetic children, provided that age is taken into account.

Insulin autoantibodies and immune response to human insulin therapy in 24 type 1 (insulin-dependent) diabetic children: superiority of radio binding assay over solid phase assay

To evaluate the immunization pattern against human insulin, 24 newly diagnosed diabetic children (12 females, 12 males; mean age: 7 +/- 4 years) were treated from diagnosis onwards with semisynthetic human insulin (NOVO). Informed consent was obtained from all parents. Blood samples were taken before, 1, 2, 3, 4, 6 and 8 weeks after the start of therapy and, thereafter, at monthly intervals for 2 years. Insulin (auto) antibodies (I(A)A) were measured by radio binding assay (RBA) and by enzyme-linked immunosorbent assay (ELISA). IAA, determined by RBA, were detected in eight children. Using ELISA, IgM IA were not detected after onset of therapy. By contrast, IgG IA were found in 8 children after 2 weeks of treatment and in 12 after 1 month. Using RBA, all children had IA after 2 months of therapy, whereas with ELISA, IA remained undetectable during the study period in 8 out of 24 patients. These results confirm previous observations suggesting that the 2 methods are not interchangeable and yield different estimations of the insulin immune reaction, not only before but also after the start of insulin therapy. In addition, the detection of IA by RBA in all treated patients unambiguously demonstrates that human insulin is immunogenic in man.

Prediction of type 1 diabetes mellitus—a report on three cases

In three children (patients 1, 2 and 3) insulindependency was predicted 28, 32 and 4 months, respectively before the disease became clinically manifest, by the finding of islet cell antibodies at that time.These retrospective findings support the evidence for a long pre-diabetic phase in childhood diabetes, marked by the presence of islet cell antibodies, as well as the linkage of HLA-antigens to the susceptibility to this disease. The possibility of detecting pre-diabetic states in children before the endogenous insulin secretion decreases to the point of producing clinical symptoms support efforts by basic scientists to develop techniques for immunological intervention early in the course of the disease.