Coincidence of pollen season with the first fetal trimester together with early pet exposure is associated with sensitization to cat and dog allergens in early childhood: A Finnish population-based study.

BACKGROUND: Children whose 11th fetal week falls in pollen season (spring) reportedly have an increased risk of sensitization to food allergens. No such finding has been reported for pet allergens. OBJECTIVE: The aim of the study was to (i) evaluate the incidence of pet (dog and cat) sensitization according to the season of the 11th fetal week and (ii) whether the association between pet exposure and respective sensitization is modified by the coincidence of the 11th fetal week with pollen season. METHODS: The study population comprised all children (born between 2001 and 2006) in the province of South Karelia, Finland (N = 5920). Their data of immunoglobulin E antibodies and skin prick tests to pet allergens (N = 538) were collected from patient records and linked with questionnaire data on pet exposure. RESULTS: The seasonal incidence peak of cat sensitization was observed in children whose 11th fetal week occurred in June (7.4%) and that of dog sensitization in April (3.8%) and June (4.7%). The relative rate (RR) for cat sensitization was 2.92 (95% CI 1.40-6.08) in children with cat exposure alone, 8.53 (4.07-17.86) in children with cat and fetal pollen exposures and 0.61 (0.20-1.83) in children exposed to pollen alone, compared with children without these exposures. The respective RRs for dog sensitization were 2.17 (1.13-4.19), 4.40 (2.19-8.83) and 1.65 (0.77-3.53). CONCLUSIONS AND CLINICAL RELEVANCE: Coincidence of the first fetal trimester with pollen season strengthens the association between pet exposure and respective sensitization. Pollen exposure at early pregnancy may deviate immune system towards Th2-type reactivity promoting development of specific allergy in case allergen exposure occurred. Therefore, primary prevention of allergic diseases may need to begin during early pregnancy.

Parental confusion may result when primary health care professionals show heterogeneity in their knowledge, attitudes, and perceptions regarding infant nutrition, food allergy, and atopic dermatitis.

INTRODUCTION AND OBJECTIVES: Whether the guidelines on infant nutrition, food allergy and atopic dermatitis confer real health benefits in practice at the population level has not been deeply studied. We aimed here to characterize the knowledge, attitudes, and perceptions regarding these issues among primary health care professionals. In addition, we surveyed available parent-reported information sources and the incidence of food-related symptoms, dietary restrictions, food allergy, and atopic dermatitis among one-year-old children in the general population. MATERIALS AND METHODS: An online questionnaire was designed for public health nurses and general practitioners. In addition, parents of one-year-old children were recruited to a separate survey at the time of their regular check-up visit. RESULTS: Altogether, 80 professionals took part. The median overall knowledge score was 77% and significantly higher among the general practitioners than among the nurses (p=0.004). However, only 35% of all the professionals recognized either severe airway or cardiovascular symptoms as potential food allergy-related symptoms. Moisturizers and emollients were thought to be adequate treatment for atopic dermatitis by 56%. Among 248 one-year-old children, the incidence of food allergy was 4% and atopic dermatitis 13%. During this period, parents intentionally avoided giving at least one food to 23% of the children, yet more than 80% of these restrictions can be regarded as unnecessary. CONCLUSION: The knowledge, attitudes and beliefs regarding infant feeding, food allergy, and atopic dermatitis varied significantly among the primary care professionals. This will likely result in heterogeneous guidance practices and confusion among the families at the population level.

Analyses of regulatory CD4+ CD25+ FOXP3+ T cells and observations from peripheral T cell subpopulation markers during the development of type 1 diabetes in children.

Our aim was to study whether the aberrant amount or function of regulatory T cells is related to the development of type 1 diabetes (T1D) in children. We also set out to investigate the balance of different T cell subtype markers during the T1D autoimmune process. Treg cells were quantified with flow cytometric assay, and the suppression capacity was analysed with a carboxyfluorescein succinimidyl ester (CFSE)-based T cell suppression assay in children in various phases of T1D disease process and in healthy autoantibody-negative control children. The mRNA expression of different T cell subpopulation markers was analysed with real-time qPCR method. The proportion and suppression capacity of regulatory T cells were similar in seroconverted children at an early stage of beta cell autoimmunity and also in children with T1D when compared to healthy and autoantibody-negative children. Significant differences were observed in the mRNA expression of different T cell subpopulation markers in prediabetic children with multiple (≥ 2) autoantibodies and in children with newly diagnosed T1D when compared to the control children. In conclusion, there were no quantitative or functional differences in regulatory T cells between the case and control groups in any phase of the autoimmune process. Decreased mRNA expression levels of T cell subtype markers were observed in children with multiple islet autoantibodies and in those with newly diagnosed T1D, probably reflecting an exhaustion of the immune system after the strong immune activation during the autoimmune process or a generally aberrant immune response related to the progression of the disease.

HLA-DQB1-defined genetic susceptibility, beta cell autoimmunity, and metabolic characteristics in familial and nonfamilial insulin-dependent diabetes mellitus. Childhood Diabetes in Finland (DiMe) Study Group.

Familial aggregation of insulin-dependent diabetes mellitus (IDDM) is a common phenomenon, but the reasons behind it are poorly understood. To investigate whether there is heterogeneity between familial and nonfamilial forms of IDDM we compared genetic, immunological, and clinical characteristics of diabetic children with and without an affected first-degree relative in a population-based series of Finnish children with IDDM. The frequencies of HLA-DQB1 genotypes known to be associated with high (DQB1*0302/0201) or moderate (*0302/x) IDDM risk in the Finnish population were increased, while the proportions of DQB1 genotypes associated with low or decreased risk for IDDM were reduced in the 121 familial cases as compared with the 574 nonfamilial cases (32.7 vs. 21.3%, 41.3 vs. 35.9%, 18.3 vs. 31.4%, and 7.7 vs. 11.4%, respectively; P = 0.002). The frequencies and serum concentrations of islet cell antibodies, insulin autoantibodies, and antibodies to the 65-kD isoform of glutamic acid decarboxylase were similar at diagnosis in the familial and nonfamilial cases. The 31 first-affected cases in the multiple case families were younger at diagnosis than the nonfamilial cases (6.9 vs. 8.5 yr; P < 0.05). The 90 second-affected familial cases had less severe metabolic decompensation at diagnosis than either the first-affected familial or nonfamilial cases. In conclusion, familial aggregation of IDDM in Finland is at least partly explained by a higher frequency of IDDM susceptibility genes in families with multiple affected individuals. The lack of differences in autoantibody levels between the familial and nonfamilial cases indicates homogeneity rather than heterogeneity in the pathogenetic process of beta cell destruction.

Prediction of insulin-dependent diabetes mellitus in siblings of children with diabetes. A population-based study. The Childhood Diabetes in Finland Study Group.

An unselected population of 755 siblings of children with insulin-dependent diabetes mellitus (IDDM) was studied to evaluate the predictive characteristics of islet cell antibodies (ICA), antibodies to the IA-2 protein (IA-2A), antibodies to the 65-kD isoform of glutamic acid decarboxylase (GADA), insulin autoantibodies (IAA), and combinations of these markers. We also evaluated whether the histochemical ICA test could be replaced by the combined detection of other markers. 32 siblings progressed to IDDM within 7.7 yr of the initial sample taken at or close to the diagnosis of the index case (median follow-up, 9.1 yr). The positive predictive values of ICA, IA-2A, GADA, and IAA were 43, 55, 42, and 29%, and their sensitivities 81, 69, 69, and 25%, respectively. In contrast to the other three antibody specificities, GADA levels were not related to the risk for IDDM. The risk for IDDM in siblings with four, three, two, one, or no antibodies was 40, 70, 25, 2, and 0.8%, respectively. Combined screening for IA-2A and GADA identified 70% of all ICA-positive siblings, and all of the ICA-positive progressors were also positive for at least one of the three other markers. The sensitivity of the combined analysis of IA-2A and GADA was 81%, and the positive predictive value was 41%. In conclusion, combined screening for IA-2A and GADA may replace the ICA assay, giving comparable sensitivity, specificity, and positive predictive value. Accurate assessment of the risk for IDDM in siblings is complicated, as not even all those with four antibody specificities contract the disease, and some with only one or no antibodies initially will progress to IDDM.

Dynamic pattern of disease-associated autoantibodies in siblings of children with type 1 diabetes: a population-based study.

To study the dynamics of disease-associated humoral immune responses, we analyzed autoantibodies to the IA-2 protein (IA-2A), glutamic acid decarboxylase (GADA), and insulin (IAA) and also islet cell antibodies (ICA) in a population-based, prospective, representative series of 710 siblings (<20 years of age) of children with type 1 diabetes. Positivity for single autoantibodies was observed in 8-13% of these siblings during an average follow-up of 4 years. The overall incidence rates per 1,000 years (number of cases/person-years in parentheses) for positive seroconversion of IA-2A were nine (19/2,123), followed by six (12/2,049) for GADA, 19 (40/2,111) for IAA, and 16 (31/1965) for ICA. Positive seroconversions seemed to be associated with a young age of the sibling, HLA DR3/DR4 heterozygosity, HLA identity, and a high initial number of detectable autoantibodies. The overall incidence rates per 1,000 years (number of cases/person-years in parentheses) for inverse seroconversion of IA-2A were 76 (12/157), followed by 42 (10/237) for GADA, 460 (32/70) for IAA, and 27 (9/331) for ICA. No consistent risk factor for inverse seroconversions was present, although seroconversions were most frequent in siblings with older age, male sex, HLA phenotypes other than DR3/DR4, a small family size, and no other autoantibodies detectable at seroconversion. Altogether, these observations indicate that beta-cell autoimmunity may be induced at any age in childhood and adolescence. HLA-conferred genetic disease susceptibility is a strong determinant of persistent beta-cell autoimmunity, but environmental factors may also contribute to such autoimmunity.

Human leukocyte antigen identity and DQ risk alleles in autoantibody-positive siblings of children with IDDM are associated with reduced early insulin response. Childhood Diabetes in Finland (DiMe) Study Group.

To investigate the relationship between human leukocyte antigen (HLA)-associated genetic factors and the development of beta-cell dysfunction, we performed sequential intravenous glucose tolerance tests (IVGTTs) on 81 islet cell antibody (ICA)-positive and/or insulin autoantibody-positive healthy siblings of children with newly diagnosed insulin-dependent diabetes mellitus (IDDM). A lower glucose disappearance rate (Kg) (P < 0.5) and decreased first-phase insulin response (FPIR) (P < 0.05) were observed on multiple occasions in HLA-identical siblings compared with the haploidentical or nonidentical ones. Siblings carrying the DQB1*0302/0201, -0302/x, or -0201/x genotype also had lower FPIRs (P < or = 0.05) at several time points than those with no DQB1 risk genotype. When all IVGTTs were taken into account, DQB1*0302/0201 heterozygous siblings had an abnormally low FPIR (< 45 mU/l; 3rd percentile) in at least one test more often than did siblings with no DQB1 risk genotype (50.0% vs. 6.1%; P = 0.001). Siblings carrying either the DQB1*0602 or the DQB1*0603 protective allele had lower serum peak ICA and glutamic acid decarboxylase (GAD)65 antibody levels (P = 0.023 and 0.007, respectively) and higher FPIRs on several occasions (P < 0.05) than those with the DQB1 risk genotypes. Progression to IDDM was related to both HLA identity and the presence of the DQB1*0302/0201 genotype. Normal Kg and FPIR levels were observed in siblings who were positive for only insulin autoantibody, and none of them developed IDDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Disease-associated antibodies in offspring of mothers with IDDM.

We studied 20 infants of mothers with IDDM participating in a pilot study for a dietary intervention trial, testing the hypothesis that avoidance of cow's milk proteins early in life will reduce the risk of subsequent IDDM. The aim was to evaluate the elimination of IDDM-associated antibodies from the peripheral circulation of the infants, the possible emergence of autoantibodies indicating beta-cell destruction, and the influence of the dietary intervention and genetic disease susceptibility on the development of these autoantibodies. Transplacentally transferred islet cell antibodies (ICAs) and antibodies to the 65-kDa isoform of glutamic acid decarboxylase (GAD65As) disappeared from the peripheral circulation of most infants over the first few months of life and in all infants before the age of 9 months. Insulin antibodies were eliminated before the same age in all cases but one. The higher the initial antibody level was, the longer the time required for elimination. Four infants tested positive for insulin autoantibodies (IAAs) on at least one occasion during the first year of life, and 5 out of 16 unaffected subjects (31%) had IAAs at the age of 2 years. One infant became positive for IAA before the age of 6 months, with increasing levels later, seroconverted to positivity for ICAs and GAD65As between 6 and 9 months and presented with clinical IDDM at the age of 14 months. He had the HLA DQB1*0302/x genotype, which predisposes carriers to IDDM, and had been given the casein hydrolysate formula as supplementary milk. There were no significant differences in the levels of various autoantibodies between two groups of subjects defined either on the type of dietary intervention or the degree of genetic susceptibility. The findings indicate that transplacentally transferred antibodies related to IDDM are usually eliminated from the peripheral circulation of infants before 9 months of age and that IDDM-associated autoantibodies may emerge before the age of 6 months. Our results also illustrate that avoidance of cow's milk proteins over the first 9 months of life does not provide total protection against IDDM.

Genetic markers, humoral autoimmunity, and prediction of type 1 diabetes in siblings of affected children. Childhood Diabetes in Finland Study Group.

The relationships between genetic markers and disease-associated autoantibodies were studied in an unselected population of 701 siblings of children with type 1 diabetes, and the predictive characteristics of these markers over a period of 9 years were determined. Increased prevalences of all the antibodies were closely associated with HLA identity to the index case, the DR4 and DQB1*0302 alleles, and the DR3/4 phenotype and the DQB1*02/0302 genotype. Antibodies to GAD (GADA) were also associated with the DR3 and DQB1*02 alleles. Siblings carrying the protective DR2 and DQB1*0602-3 alleles were characterized by lower frequencies of islet cell antibodies (ICA), antibodies to IA-2 (IA-2A), and GADA. Higher levels of ICA were related to HLA identity, the DR4 and DQB1*0302 alleles, and the susceptible DQB1 genotypes, while no significant differences were observed in the levels of IA-2A, GADA, or insulin autoantibodies among siblings with different HLA risk markers. The DR2 or DQB1*0602-3 alleles were not related to the levels of any antibody specificity. A combination of the genetic markers and autoantibodies increased the positive predictive values of all autoantibodies substantially, which may have clinical implications when evaluating the risk of developing type 1 diabetes at the individual level or when recruiting high-risk individuals for intervention trials. However, because such combinations also resulted in reduced sensitivity, autoantibodies alone rather than in combination with genetic markers are recommended as the first-line screening in siblings. Finally, not all siblings with a broad humoral autoimmune response or high-risk genetic markers present with type 1 diabetes, while some with a low genetic risk and weak initial signs of humoral autoimmunity may progress to disease.

Clinical, autoimmune, and genetic characteristics of very young children with type 1 diabetes. Childhood Diabetes in Finland (DiMe) Study Group.

OBJECTIVE: To study the characteristics of type 1 diabetes in very young children. RESEARCH DESIGN AND METHODS: Clinical outcome, islet cell antibodies (ICA), insulin autoantibodies (IAA), antibodies against GAD (GADA), IA-2 antibodies (IA-2A), and HLA-DQB1-defined genetic risk were analyzed in 35 children diagnosed with type 1 diabetes before 2 years of age and compared with those in 146 children who were diagnosed between 2.0 and 4.9 years of age and with those in 620 children diagnosed between 5.0 and 14.9 years of age. RESULTS: The youngest age-group had severer metabolic decompensation at clinical onset, and their serum C-peptide levels, compared with those of older children, were lower at the time of diagnosis and during the first 2 years after the diagnosis. The levels of ICA and IAA were highest in children < 2 years of age, but there were no differences in GADA levels among the three age-groups. The youngest age-group had the lowest IA-2A levels. The HLA DQB1*02/*0302 genotype associated with strong genetic susceptibility was more frequent in children diagnosed < 5 years of age, whereas the proportion of children carrying a genotype, which includes protective alleles, was higher among those diagnosed at > or = 5 years of age. CONCLUSIONS: The clinical presentation of type 1 diabetes at a very young age is associated with severe metabolic decompensation, poorly preserved residual beta-cell function, strong humoral autoimmunity against islet cells and insulin, and strong HLA-defined disease susceptibility.

Genetic, autoimmune, and clinical characteristics of childhood- and adult-onset type 1 diabetes.

OBJECTIVE: To assess whether there are any differences in genetic, autoimmune, or clinical features between type 1 diabetes presenting in childhood and that diagnosed later. RESEARCH DESIGN AND METHODS: We studied 352 individuals (252 children and adolescents <20 years of age and 100 adults > or =20 years of age) manifesting clinical signs of type 1 diabetes over a period of 7.5 years at a university hospital in northern Finland with a primary catchment area population of approximately 300,000. The patients were analyzed for susceptible and protective HLA-DQB1 alleles (*02, *0302, *0301, *0602, *0603, and *0604), islet cell antibodies (ICA), insulin autoantibodies, and antibodies to GAD and IA-2 (IA-2A). Their clinical symptoms and signs were recorded at diagnosis. RESULTS: The adult patients carried the high-risk DQB1*02/0302 genotype less frequently than the children and more often had protective genotypes. They also had a decreased frequency of all 4 single autoantibody specificities and of multiple (> or =3) autoantibodies. The proportion of patients testing negative for all autoantibodies was lower among the children than among the adults. IA-2A were associated with the DQB1*0302/x genotype in both the children and adults, and the same held true for ICA among the adults. The adults were characterized by a higher proportion of males, a longer duration of symptoms, and a lower frequency of infections during the preceding 3 months. In addition, they had a higher relative body weight on admission and milder signs of metabolic decompensation (higher pH, base excess, and bicarbonate concentrations) and a lower glycated hemoglobin level at diagnosis than the children. CONCLUSIONS: Clinical manifestation of type 1 diabetes before the age of 20 years is associated with a strong HLA-defined genetic disease susceptibility, an intensive humoral immune response to various beta-cell antigens, a higher frequency of preceding infections, and a shorter duration of symptoms and more severe metabolic decompensation at diagnosis. Taken together, these observations suggest that the age at clinical onset of type 1 diabetes is determined by the intensity of the beta-cell-destructive process, which is modulated by both genetic and environmental factors.

Genetic modification of risk assessment based on staging of preclinical type 1 diabetes in siblings of affected children.

We set out to study the association between human leukocyte antigen-defined genetic disease susceptibility and the stage of preclinical type 1 diabetes and whether genetic predisposition affects the natural course of preclinical diabetes in initially nondiabetic siblings of affected children. A total of 701 initially unaffected siblings were graded into four stages of preclinical type 1 diabetes based on the initial number of disease-associated autoantibodies detectable close to the time of diagnosis of the index case: no prediabetes (no antibodies), early (one antibody specificity), advanced (two antibodies), and late prediabetes (three or more antibodies). Another classification system covering 659 siblings was based on a combination of the initial number of antibodies and the first-phase insulin response (FPIR) to iv glucose: no prediabetes (no antibodies), early (one antibody specificity, normal FPIR), advanced (two or more antibodies, normal FPIR), and late prediabetes (at least one antibody, reduced FPIR). Genetic susceptibility to type 1 diabetes was defined by human leukocyte antigen identity and DR and DQ genotypes. There was a higher proportion of siblings with late prediabetes initially among those with strong genetic disease susceptibility than among those with decreased genetic predisposition (16.7% vs. 0.5%; P < 0.001 for DQB1 genotypes according to the first classification), whereas there was a higher proportion of siblings with no signs of prediabetes among those with genotypes conferring decreased risk (91.2% vs. 70.4% among those with high-risk DQB1 genotypes; P < 0.001 according to the first classification). Autoantibodies alone were more sensitive in the prediction of future diabetes in siblings than when combined with genetic susceptibility. Genetic susceptibility played a role in whether the initial prediabetic stage progressed (progression in 29.6% of the high-risk siblings compared with 6.6% of the siblings with DQB1 genotypes conferring decreased risk; P < 0.001 according to the first classification) and whether overt type 1 diabetes became manifest or not. Genetic susceptibility has an impact on both the initiation and progression of the autoimmune process leading to clinical diabetes in siblings of affected children.

Diabetes-associated autoantibodies in relation to clinical characteristics and natural course in children with newly diagnosed type 1 diabetes. The Childhood Diabetes In Finland Study Group.

We analyzed 747 children, younger than 15 yr of age, with newly diagnosed diabetes, for antibodies to glutamic acid decarboxylase (GADA), the IA-2 protein (IA-2A), insulin (IAA), and islet cells, to evaluate the influence of positivity for GADA, IA-2A, IAA, or multiple (> or = 3) autoantibodies at diagnosis, on the clinical presentation and natural course of the disease over the first 2 yr and to characterize autoantibody-negative patients. At diagnosis, 73.2% of the children tested positive for GADA, 85.7% for IA-2A, 54.2% for IAA, and 72.6% for multiple autoantibodies. Only 17 subjects (2.3%) had no detectable autoantibodies. The patients testing positive for multiple autoantibodies were younger than the remaining children (P < 0.001). A similar age difference was seen when comparing IAA-positive and -negative patients (P < 0.001). There was no significant difference between the GADA-positive and -negative subjects in the degree of metabolic decompensation at diagnosis, whereas those testing positive for IA-2A had reduced serum C-peptide concentrations (P = 0.003), and those positive for IAA had lower glycated hemoglobin values. The patients with no detectable autoantibodies had higher serum C-peptide levels (P = 0.007) at diagnosis than did the other subjects. The children initially positive for IA-2A had decreased serum C-peptide concentrations at 24 months (P = 0.045), and their daily insulin dose was higher at 18 (P = 0.005) and 24 months (P < 0.001). The patients who tested positive for multiple autoantibodies at diagnosis had decreased serum C-peptide levels (P < 0.001) and higher insulin doses (P = 0.005) at 12, 18, and 24 months. A lower proportion of them were also in clinical remission at 12 and 18 months (P = 0.01). Autoantibody-negative subjects needed less exogenous insulin at 6 and 18 (P = 0.01) and at 24 months (P < 0.001) than the other subjects, and a higher proportion of them were in clinical remission at 18 months (P < 0.001). We conclude that positivity for multiple diabetes-related autoantibodies is associated with accelerated beta-cell destruction and an increased requirement for exogenous insulin over the second year of clinical disease, indicating that multiple autoantibodies reflect an aggressive progression to total beta-cell destruction. Patients testing negative for diabetes-associated autoantibodies at diagnosis seem to have a milder degree of beta-cell destruction, but their metabolic decompensation is similar to that seen in other affected children, suggesting that they do represent classical type 1 diabetes.

Natural history of beta-cell autoimmunity in young children with increased genetic susceptibility to type 1 diabetes recruited from the general population.

The aim of this study was to evaluate the frequency and predictive value of diabetes-associated autoantibodies, such as islet cell antibodies (ICA) and autoantibodies to insulin (IAA), GAD65 (GADA), and the IA-2 molecule (IA-2A) in genetically susceptible children from the general population during the first 2 yr of life. Of 12,170 newborn infants, 1,005 with increased genetic risk of type 1 diabetes (high risk, human leukocyte antigen DQB1*02/*0302; moderate risk, DQB1*0302/x, where x = other than *02, *0301, or *0602) were monitored for ICA, IAA, GADA, and IA-2A at 3- to 6-month intervals from birth up to a minimum age of 2 yr. In addition, all 15 genetically susceptible children from the general population who had participated in regular immunological follow-up and developed clinical type 1 diabetes by the end of April 2000 were analyzed for the development of autoantibodies. Among 1,005 children, 63 (6.3%) tested positive for at least one autoantibody, 31 for ICA (3.1%), 48 for IAA (4.8%), 23 for GADA (2.3%), and 13 for IA-2A (1.3%) at least once by the age of 2 yr. Both ICA and IAA identified 95% [95% confidence interval (CI), 77.2-99.9%] of those who tested persistently positive for multiple (> or = 2) antibodies at the age of 2 yr, GADA identified 86% (CI, 65.1-97.1%), and IA-2A identified 55% (CI, 32.2-75.6%). Close to half of the antibody-positive children (29 of 63) reverted back to antibody negativity. Autoantibodies disappeared more often among those who tested positive for IAA than among those who tested positive for other autoantibodies (P < or = 0.021). Among the 15 children who developed type 1 diabetes, the disease sensitivity of ICA was 80% (CI, 51.9-95.7%), that of IAA was 93% (CI, 68.0-99.8%), that of GADA was 60% (CI, 32.3-83.7%), and that of IA-2A was 40% (CI, 16.3-67.7%). These results suggest that IAA are characterized by high sensitivity, early appearance, and high frequency of transient antibody positivity, whereas ICA detected with a thoroughly standardized assay appear to be more specific for the screening of beta-cell autoimmunity in young children with increased genetic susceptibility to type 1 diabetes in the Finnish population, which has the highest incidence of type 1 diabetes in the world.

Glutamic acid decarboxylase antibodies in relation to other autoantibodies and genetic risk markers in children with newly diagnosed insulin-dependent diabetes. Childhood Diabetes in Finland Study Group.

To study the frequency of antibodies to glutamic acid decarboxylase (GAD65A) at the diagnosis of insulin-dependent diabetes mellitus (IDDM) and to evaluate the relation of these antibodies to other IDDM-associated autoantibodies and genetic risk markers of the disease, we analyzed 747 newly diagnosed diabetic children younger than 15 yr of age (mean, 8.4 yr) for GAD65A, islet cell antibodies, insulin autoantibodies, and human leukocyte antigen DR alleles. GAD65A were detected in 73.2% of the children, with a higher frequency in females than in males (77.1% vs. 70.1%; P = 0.04) and in index cases aged 10 yr or older than in younger children (79.0% vs. 68.7%; P = 0.004). The index cases positive for GAD65A had higher levels of islet cell antibodies (median, 40 vs. 34 Juvenile Diabetes Foundation units; P = 0.003) and insulin autoantibodies (median, 55 vs. 43 nU/mL; P = 0.03) than those testing negative for GAD65A. Human leukocyte antigen DR3/non-DR4 children had the highest GAD65A levels, whereas DR2-positive cases had levels of GAD65A similar to those found in other subjects. One third of the index cases (33.9%) tested positive for all three autoantibodies, 43.1% for two antibodies, and 18.2% for one antibody, whereas 4.8% were triple negative. The females had multiple antibodies (at least two antibodies) more often than the males (81.3% vs. 73.5%; P = 0.01). There was a significant trend for a higher frequency of multiple antibodies in young children (83.0% in those under 5 yr and 73.2% in those 10 yr or older; P = 0.02) and a higher frequency in DR3/4 heterozygous children than in those with DR3/non-DR4 (83.3% vs. 63.2%; P = 0.02). The results show that GAD65A antibodies are more frequent in girls and adolescents with newly diagnosed IDDM and suggest that DR3/non-DR4 subjects have increased GAD65A levels. Multiple antibodies in diabetic children are associated with young age, female sex, and DR3/4 heterozygosity.

The first signs of beta-cell autoimmunity appear in infancy in genetically susceptible children from the general population: the Finnish Type 1 Diabetes Prediction and Prevention Study.

Little is known about the timing of the etiological events and the preclinical process of type 1 diabetes during the first years of life in the general population. In this population-based prospective birth cohort study, the appearance of diabetes-associated autoantibodies as a sign of beta-cell autoimmunity and the development of type 1 diabetes were monitored from birth. Of 25,983 newborn infants, 2,448 genetically susceptible children were monitored for islet cell antibodies (ICA) at 3- to 6-month intervals. If an infant seroconverted to ICA positivity, all his/her samples were also analyzed for insulin autoantibodies (IAA), antibodies to the 65-kDa isoform of glutamic acid decarboxylase, and antibodies to the protein tyrosine phosphatase-related IA-2 molecule. Fifteen children of those who carried the high-risk genotype (2.7%) and 23 of those who carried the moderate-risk genotype (1.2%; P = 0.019) tested positive for ICA at least once. Among those who showed positivity for at least 2 antibodies during the observation period (25 of 38), IAA appeared as the first or among the first antibodies in 22 children (88%) and emerged earlier than the other antibodies (P < 0.019 or less). The first autoantibodies appeared in the majority of the children in the fall and winter (30 of 38 vs. 8 of 38 in the spring and summer, P < 0.001). These observations suggest that young children in the general population with a strong human-leukocyte-antigen-DQ-defined genetic risk of type 1 diabetes show signs of beta-cell autoimmunity proportionally more often than those with a moderate genetic risk. IAA emerge as the first detectable antibody more commonly than any other antibody specificity, implying that insulin may be the primary antigen in most cases of human type 1 diabetes associated with the DR4-DQB1*0302 haplotype. The seasonal variation in the emergence of the first signs of beta-cell autoimmunity suggests that infectious agents may play a role in the induction of such autoimmunity.

Disease-associated autoantibodies as surrogate markers of type 1 diabetes in young children at increased genetic risk. Childhood Diabetes in Finland Study Group.

To evaluate the emergence of diabetes-associated autoantibodies in young children and to assess whether such antibodies can be used as surrogate markers of type 1 diabetes in young subjects at increased genetic risk, we studied 180 initially unaffected siblings (92 boys and 88 girls) of children with newly diagnosed type 1 diabetes. All siblings were younger than 6 yr of age at the initial sampling, and they were monitored for the emergence of islet cell antibodies (ICA), insulin autoantibodies (IAA), glutamate decarboxylase antibodies (GADA), and IA-2 antibodies (IA-2A) up to the age of 6 yr and for progression to clinical type 1 diabetes up to the age of 10 yr. All 160 siblings with DNA samples available were typed for susceptible (DQB1*02 and *0302) and protective (DQB1*0301 and *0602-03) HLA DQB1 alleles. Twenty-two siblings (12.2%) tested positive for ICA in their first antibody-positive sample before the age of 6 yr, 13 (7.2%) tested positive for IAA, 15 (8.3%) tested positive for GADA, and 14 (7.8%) tested positive for IA-2A. There were 16 siblings (8.9%) who had 1 detectable autoantibody, 5 (2.8%) had 2, and 12 (6.7%) had 3 or more. In the group of 82 siblings with increased human leukocyte antigen-defined genetic susceptibility [DQB1*02/*0302, *0302/x (x = other than *02 or a protective allele), *02/y (y = other than *0302 or a protective allele)], 18 (22.0%) tested positive for ICA in their first antibody-positive sample, 10 (12.2%) tested positive for IAA, 14 (17.1%) tested positive for GADA, and 12 (14.6%) tested positive for IA-2A. One antibody was detectable in 6 siblings (7.3%), 2 were detectable in 5 (6.1%), and 3 or more were detectable in 12 (14.6%). Fifteen siblings (18.3%) presented with clinical type 1 diabetes before the age of 10 yr. All of the progressors showed increased human leukocyte antigen-defined genetic susceptibility. Thirteen of those 15 siblings, who presented with clinical type 1 diabetes before the age of 10 yr, had at least 2 antibodies detectable before the age of 6 yr (disease sensitivity, 87%; 95% confidence interval, 60-98%). Thirteen of the 17 siblings who tested positive for 2 or more autoantibodies before the age of 6 yr developed type 1 diabetes before the age of 10 yr (positive predictive value, 76%; 95% confidence interval, 50-93%). These observations suggest that disease-associated autoantibodies can well be used as surrogate markers of clinical type 1 diabetes in primary prevention trials targeting young subjects with increased genetic disease susceptibility.

Autoantibodies to glutamic acid decarboxylase in patients with therapy-resistant epilepsy.

BACKGROUND: Autoantibodies to glutamic acid decarboxylase (GAD-A) are present in type 1 diabetes and stiff man syndrome (SMS), and have also been reported in cerebellar ataxia. Epilepsy was present in 4 of 19 patients with SMS and GAD-A, implying that epilepsy sometimes is associated with anti-GAD autoimmunity. METHODS: The authors investigated the prevalence of GAD-A in patients with therapy-resistant localization-related epilepsy (n = 51) and generalized epilepsy (n = 49) by a radiobinding assay. The positive samples were confirmed by immunohistochemistry and immunoblotting of recombinant human GAD65. RESULTS: GAD-A were found in eight patients with localization-related epilepsy, whereas none of the patients with generalized epilepsy, other neurologic disorders (n = 38), or the control subjects (n = 48) had GAD-A. Two patients had high levels of GAD-A, similar to SMS, whereas six patients had significantly lower titers, characteristic of type 1 diabetes. The two patients with high levels of GAD-A had GAD-A both in serum and CSF by immunohistochemistry and immunoblotting. Both of them had longstanding therapy-resistant temporal lobe epilepsy but did not have diabetes. One had a history of autoimmune disease, whereas the other had serologic evidence of multiple autoantibodies without any clinical signs of autoimmune disease. CONCLUSIONS: GAD autoimmunity may be associated with refractory localization-related epilepsy.

Antiphospholipid and antinuclear antibodies in patients with epilepsy or new-onset seizure disorders.

PURPOSE: The increased prevalence of autoantibodies in patients with epilepsy has been traditionally regarded to be a consequence of antiepileptic drugs. The purpose of this study was to measure autoantibodies in well-defined groups of patients with seizures to determine the effects of epilepsy and antiepileptic medications on the presence of autoantibodies. PATIENTS AND METHODS: We studied the frequency of antinuclear antibodies, anti-beta2-glycoprotein I antibodies, and anticardiolipin antibodies in 50 patients with therapy-resistant localization-related epilepsy, 50 patients with generalized epilepsy syndromes, 52 patients with a newly diagnosed seizure disorder but no antiepileptic medication, and 83 healthy controls. RESULTS: Compared with controls, newly diagnosed patients had a significantly greater prevalence of immunoglobulin (Ig) G class anticardiolipin antibodies (21% versus 7%); the prevalence was 14% in patients with localization-related epilepsy and 8% in patients with generalized epilepsy. The prevalence of IgM class anticardiolipin antibodies was significantly greater in all seizure groups (60% in localization-related epilepsy, 42% in generalized epilepsies, and 33% in newly diagnosed patients) compared with controls (7%). Antinuclear antibodies were significantly more common in newly diagnosed patients (21%) and localization-related epilepsy (24%) compared with controls (12%). When patients with generalized epilepsy (8%) were used as the reference group, antinuclear antibodies were also significantly more frequent in localization-related epilepsy (relative risk [RR] = 2.9, 95% confidence interval [CI]: 1.1 to 8.2) and newly diagnosed seizures (RR = 3.4, 95% CI: 1.2 to 9.3). There were no consistent associations between autoantibodies and specific antiepileptic medications. CONCLUSIONS: The prevalence of autoantibodies is greater in patients with epilepsy, including newly diagnosed seizure disorder. The increased prevalence of autoantibodies is more strongly associated with epilepsy than with antiepileptic drugs, perhaps indicating that immune dysregulation may be commonly associated with epilepsy.

Staging of preclinical type 1 diabetes in siblings of affected children. Childhood Diabetes in Finland Study Group.

OBJECTIVES: To assess whether it is clinically relevant to classify siblings of children with recent-onset type 1 diabetes mellitus (T1DM) into various stages of preclinical diabetes, and to compare the risk of developing clinical disease and the time to diagnosis between these stages. STUDY DESIGN: From a total of 801 families taking part in the Childhood Diabetes in Finland Study, 758 initially unaffected siblings were graded into four stages of preclinical T1DM based on the number of disease-associated autoantibodies detectable close to the time of diagnosis in the index case: no (no antibodies), early (one antibody specificity), advanced (two antibodies), and late prediabetes (more than three antibodies). Another classification system, used with 712 siblings, was based on a combination of the number of antibodies and the first-phase insulin response (FPIR) to intravenous glucose: no (no antibodies), early (one antibody specificity, normal FPIR), advanced (two or more antibodies, normal FPIR), and late prediabetes (one or more antibodies, reduced FPIR). RESULTS: Six out of 661 siblings who initially presented no signs of prediabetes (0.9%; 95% confidence interval [CI], 0.3%-2.0%) progressed to clinical T1DM. Based on the first set of criteria, 3 out of 49 individuals (6.1%; CI, 1.3%-16. 9%; odds ratio [OR], 7.1; CI, 1.7-29.4) from the early prediabetes category, 3 out of 13 with advanced prediabetes (23.1%; CI, 5.0%-53. 8%; OR, 32.8; CI, 7.2-150), and 23 out of 35 with late prediabetes (65.7%; CI, 47.8%-80.9%; OR, 209; CI, 72.2-607) presented with clinical signs of T1DM. According to the second set of criteria 1 out of 15 siblings with early prediabetes (6.7%; CI, 0.2%-32.0%; OR, 7.8; CI, 0.9-69.1), 6 out of 23 with advanced prediabetes (26.1%; CI, 10.2%-48.4%; OR, 38.5; CI, 11.3-132), and 12 out of 13 with late prediabetes (92.3%; CI, 64.0%-99.8%; OR, 1310; CI, 146-11 737) presented with clinical signs of T1DM. The time to diagnosis was significantly shorter in those with late prediabetes initially than in those with no signs of prediabetes. CONCLUSIONS: Our observations indicate that it is possible to grade siblings of children with newly diagnosed T1DM into categories with significant differences in the subsequent risk of clinical T1DM and time to diagnosis. Such a classification will become clinically relevant as soon as effective measures are available for preventing or delaying the manifestation of overt T1DM.autoantibodies, classification, prospective, first-phase insulin response.