AIMS: To compare levels of insulin antibodies in children and adolescents after initiation of insulin therapy using either insulin aspart (IAsp) or human insulin (HI) in combination with Neutral Protamine Hagedorn (NPH) insulin, and to investigate the relationships between insulin antibodies and HbA(1c) and insulin dose. METHODS: IAsp-specific antibodies (IAsp-Ab) and antibodies cross-reacting with HI and IAsp (HI-cross-Ab) were analysed by radioimmunoassay at diagnosis of diabetes and every 3-6 months for 30 months. Seventy-two patients (HI = 30, IAsp = 42) with Type 1 diabetes, aged 2-17 years were included. Data on HbA(1c), insulin dose and serious adverse events (SAEs) were collected retrospectively. RESULTS: IAsp-Ab levels remained low throughout the study. After 9 months, the level of HI-cross-Ab increased [mean (SD) HI, 48.8% (21.53), IAsp, 40.2% (17.92)] and remained elevated. Repeated measurement analysis of HI-cross-Ab levels showed no significant difference between treatments (P = 0.16). HI-cross-Ab were significantly associated with total insulin dose (U/kg) (P = 0.001) and time (P < 0.0001), but not with HbA(1c) (P = 0.24). Mean (+/- SD) HbA(1c) was similar at diagnosis (HI 9.5 +/- 1.97%, IAsp 9.6 +/- 1.62%), HbA(1c) then decreased and stabilized to about 6.0% in both groups. Few SAEs were reported, the majority being hypoglycaemic episodes. CONCLUSIONS: Treatment with IAsp and with HI was associated with an increase in HI-cross-Ab in insulin-naive children, but this did not influence treatment efficacy or safety. These results support the safe use of IAsp in children and adolescents with Type 1 diabetes.

Breast-feeding has been suggested to have a protective effect against the development of type 1 diabetes. In the present study, we investigated the relation between duration of breast-feeding and β-cell autoantibodies in 5-year-old non-diabetic children who participated in a prospective population-based follow-up study (the All Babies in Southeast Sweden study). Autoantibodies to insulin (IAA), glutamic acid decarboxylase (GADA) and the protein tyrosine phosphatase-like IA-2 (IA-2A) were measured by radiobinding assays. A short duration of total breast-feeding was associated with an increased risk of GADA and/or IAA above the ninety-fifth percentile at 5 years of age (OR 2-09, 95% CI 1-45, 3-02; P<0-000) as well as with an increased risk of IAA above the ninety-fifth percentile at this age (OR 2-89, 95% CI 1-81, 4-62; P<0-000). A short duration of exclusive breast-feeding was associated with an increased risk of GADA, IAA and/or IA-2A above the ninety-ninth percentile (OR 2-01, 95% CI 1-08, 3-73; P = 0-028) as well as with an increased risk of IA-2A above the ninety-ninth percentile (OR 3-50, 95% CI 1-38, 8-92; P = 0-009) at 5 years of age. An early introduction of formula was associated with an increased risk of GADA, IAA and/or IA-2A above the ninety-ninth percentile (OR 1-84, 95% CI 1-01, 3-37; P = 0-047) at 5 years of age. The positive association between a short duration of both total and exclusive breast-feeding, as well as an early introduction of formula, and positivity for β-cell autoantibodies in children from the general population suggests that breast-feeding modifies the risk of β-cell autoimmunity, even years after finishing breast-feeding.

We have developed high-throughput tests for the detection of the insulin gene region SNPs -23HphI and -2221MspI. The potential of these markers to enhance the efficiency of type 1 diabetes risk screening was then evaluated by analyzing them in Finnish and Swedish populations. Blood spots on filter paper were analyzed using PCR followed by sequence-specific hybridization and time-resolved fluorometry reading. Distribution of the genotypes at both positions differed significantly among the affected children compared to the controls. The risk genotypes (CC, AA) were significantly more common in Finland than in Sweden, both among patients and controls. The VNTR genotype homozygous for the protective class III alleles showed a significantly stronger protective effect than the heterozygote (p=0.02). Analyzing both SNPs enabled the detection of VNTR class III subclasses IIIA and IIIB. The observed significance between effects of the protective genotypes was due to the strong protective effect of the IIIA/IIIA genotype. IIIA/IIIA was the only genotype with significant discrepancy between protective effects compared to the other class III genotypes. These observations suggest that heterogeneity between the protective IDDM2 lineages could exist, and analyzing both -23HphI and -2221MspI would thus potentially enhance the sensitivity and specificity of type 1 diabetes risk estimation.

Type 1 diabetes (T1D) is a chronic disease caused by destruction of the insulin producing beta-cells in the pancreas. The incidence of T1D has increased rapidly, especially in the Western world and among young children. The pathogenesis of T1D is not fully understood, but the beta-cells are believed to be destroyed by an autoimmune process initiated years before the onset of T1D. During this pre-clinical

period, autoantibodies to insulin (IAA), glutamic acid decarboxylase (GADA) and the tyrosine phosphatase-like protein IA-2 (IA-2A) can be detected and are used to identify individuals at risk of T1D. The major genetic determinant for T1D is the HLA class II genes, but also polymorphism in the insulin gene and CTLA-4 gene are associated with T1D. The risk genes cannot explain the rapid increase in incidence of T1D, therefore a role for different environmental factors has been suggested.

The aim was to study the prevalence of beta-cell autoantibodies in children from the general population in relation to known genetic and environmental risk factors, and in young patients with T1D in high and low incidence areas.

Short duration of breast-feeding was associated with an increased risk of developing beta-cell autoantibodies in children from the general population at 5-6 years of age. We found an association between positivity for GADA and/or IAA at the age of 5-6 years and a short duration of total breastfeeding, and also between positivity for GADA, IA-2A and/or IAA and a short duration of exclusive breast-feeding. Our findings suggest that breast-feeding has a long term protective effect on the risk of beta-cell autoimmunity in children from the general population. The T1D related risk genes were not associated with beta-cell autoantibodies other than GADA in children from the general population at 5-6 years of age. Children with the DR4-DQ8 haplotype were more often positive for GADA than children without this haplotype. We found no association of GADA with DR3-DQ2 haplotype or between these two haplotypes and any of the other autoantibodies. Our results suggest that beta-cell autoimmunity in children from the general population is not strongly associated with any risk genes of T1D other than DR4-DQ8. In the non-diabetic children with allergic heredity GADA was detectable in almost all children, IA-2A in about half and IAA in 10% of the children. The levels low of these autoantibodies fluctuated with age and different patterns of fluctuations were seen for GADA and IA-2A, which may reflect differences in the immune response to the autoantigens. In patients with newly diagnosed T1D, we found some differences between patients from a high incidence country (Sweden) and a country with a lower incidence (Lithuania). Among the Swedish patients, the prevalence of IAA and GADA or multiple autoantibodies was higher than in Lithuanian patients. The risk genes DR4-DQ8 and the heterozygous high risk combination DR4-DQ8/DR3-DQ2 was more common among the Swedish patients than Lithuanian patients. Patients with low levels of IAA had higher levels of HbA1c and ketones, indicating that patients without IAA or with low levels of IAA have a more severe onset of T1D. Our findings indicate that beta-cell autoimmunity is more pronounced in a high incidence area compared to an area with a lower incidence.

In conclusion, short duration of breast-feeding is a risk factor for beta-cell autoantibodies in children from the general population, and the beta-cell autoantibodies in these children are not associated with specific risk genes. Children with newly diagnosed T1D in a high incidence area carry risk genes and have autoantibodies more often than newly diagnosed children from an area with a lower incidence, perhaps indicating different disease phenotypes.

Enteroviruses, particularly Coxsackie virus B4 (CVB4), are considered to be involved in the pathogenesis of type 1 diabetes. We wanted to compare the characteristics of T-cell immune response to CVB4 in children with type 1 diabetes and healthy children with and without HLA risk-associated haplotypes (HLA-DR3-DQ2 or HLA-DR4-DQ8) for type 1 diabetes. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with CVB4 and analyzed for cytokine and chemokine receptors by flow cytometry and for expression of transcription factors Tbet and GATA-3 by RT-PCR and Western blot. Culture supernatants were analyzed for secretion of γ-interferon (IFN-γ). In children with type 1 diabetes, a decreased percentage of T-cells expressed CCR2, CXCR6, interleukin (IL)-18R, and IL-12Rβ₂-chain after in vitro stimulation with CVB4 in comparison with healthy children with or without HLA risk genotype. Moreover, we found that children with type 1 diabetes had decreased IFN-γ secretion and expression of Tbet, both on mRNA and protein level, in CVB4-stimulated PBMCs. Accordingly, children with type 1 diabetes show an impaired type 1 immune response against CVB4 compared with healthy children. This may lead to a delayed clearance of the virus and, at least partly, explain why children with type 1 diabetes may be more prone to CVB4 infections and related complications, such as β-cell damage.

We compared the prevalence of beta-cell autoantibodies and genetic risk factors in Sweden and Lithuania. Ninety-six patients from Sweden and 96 from Lithuania matched for age and gender (1–15 years old, median age 9.0 years) were included. We analyzed autoantibodies to insulin (IAA), glutamic acid decarboxylase (GADA) and the protein tyrosine phosphatase like IA-2 (IA-2A) as well as risk-associated polymorphisms of HLA, insulin and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) genes.

The frequency of patients positive for IAA and GADA was higher in Sweden than in Lithuania (p=0.043 and 0.032). The differences remained even when the patients were matched for HLA, insulin and CTLA-4 risk genotypes. Patients with low levels of IAA had higher levels of HbA1c and ketones at diagnosis. The frequency of the risk haplotype DR4-DQ8 was higher in Swedish than in Lithuanian patients (p=0.004), as well as the high-risk combination of DR4-DQ8 and DR3-DQ2 haplotypes (p=0.009).

Our results suggest that autoimmune process against insulin and GAD65 is more common at diagnosis in children in areas with high incidence of type 1 diabetes (T1D), independent of genetic risk markers. Furthermore, the disease in patients with insulin autoantibodies seems to be clinically milder.

The aim was to study the natural course of diabetes-related autoantibodies at low concentrations, below "positivity", in a nondiabetic population followed up from infancy. Blood samples were taken from 205 children at 6 weeks, 6 months, 18 months, and 5 years of age. Autoantibodies against GAD₆₅ (GADA), tyrosine phosphatase (IA-2A), and insulin (IAA) were determined by radioligand-binding assays. All children had detectable levels of GADA and approximately half had IA-2A, but only approximately 10% had detectable levels of IAA during the follow-up period. Many children developed IA-2A already at 6 months of age, similar concentrations were seen at 18 months, and then the levels of IA-2A decreased until 5 years of age. GADA were induced less often at 6 months of age, increased up to 18 months, and fluctuated at similar levels up to 5 years of age. IAA were detectable in so few children and at low levels, so no trend in natural course could be revealed. We conclude that there is a natural induction of humoral immune response to β cell autoantigens early in life. Our results suggest that the mechanisms of β cell tolerance to GAD and IA-2 differ in healthy children.