Ville Simell

Risk of Pediatric Celiac Disease According to HLA Haplotype and Country

BACKGROUND The presence of HLA haplotype DR3-DQ2 or DR4-DQ8 is associated with an increased risk of celiac disease. In addition, nearly all children with celiac disease have serum antibodies against tissue transglutaminase (tTG). METHODS We studied 6403 children with HLA haplotype DR3-DQ2 or DR4-DQ8 prospectively from birth in the United States, Finland, Germany, and Sweden. The primary end point was the development of celiac disease autoimmunity, which was defined as the presence of tTG antibodies on two consecutive tests at least 3 months apart. The secondary end point was the development of celiac disease, which was defined for the purpose of this study as either a diagnosis on biopsy or persistently high levels of tTG antibodies. RESULTS The median follow-up was 60 months (interquartile range, 46 to 77). Celiac disease autoimmunity developed in 786 children (12%). Of the 350 children who underwent biopsy, 291 had confirmed celiac disease; an additional 21 children who did not undergo biopsy had persistently high levels of tTG antibodies. The risks of celiac disease autoimmunity and celiac disease by the age of 5 years were 11% and 3%, respectively, among children with a single DR3-DQ2 haplotype, and 26% and 11%, respectively, among those with two copies (DR3-DQ2 homozygosity). In the adjusted model, the hazard ratios for celiac disease autoimmunity were 2.09 (95% confidence interval [CI], 1.70 to 2.56) among heterozygotes and 5.70 (95% CI, 4.66 to 6.97) among homozygotes, as compared with children who had the lowest-risk genotypes (DR4-DQ8 heterozygotes or homozygotes). Residence in Sweden was also independently associated with an increased risk of celiac disease autoimmunity (hazard ratio, 1.90; 95% CI, 1.61 to 2.25). CONCLUSIONS Children with the HLA haplotype DR3-DQ2, especially homozygotes, were found to be at high risk for celiac disease autoimmunity and celiac disease early in childhood. The higher risk in Sweden than in other countries highlights the importance of studying environmental factors associated with celiac disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Fate of Five Celiac Disease-Associated Antibodies During Normal Diet in Genetically At-Risk Children Observed from Birth in a Natural History Study

OBJECTIVES: To explore the natural history of antibodies against tissue transglutaminase (TGA), endomysium (EMA), reticulin (ARA), and gliadin (AGA-IgG and AGA-IgA) in children carrying HLA-conferred risk for celiac disease (CD) and observed frequently from birth.METHODS: TGA was measured in serum samples obtained between years 2000 and 2003 from 1,320 children carrying genetic CD risk. If a sample was TGA positive, all five antibodies were analyzed in all banked and forthcoming samples from that child, and a duodenal biopsy was recommended. At the end of this observation, in August 2004, the age of the children was from 1 to 9.5 yr (mean 4.1 yr).RESULTS: Forty-nine children (3.7%) were TGA positive. In these children, AGA-IgG had emerged at the mean age (± SD, range) of 2.0 ± 1.5, 0.5–6.6 yr, while TGA, EMA, and ARA all emerged concurrently somewhat later (TGA at 3.2 ± 1.5, 1.0–7.0 yr, P < 0.001 when compared to AGA-IgG). Despite continuing gluten exposure, positive TGA, EMA, ARA, AGA-IgA, and AGA-IgG values were spontaneously lost in 49%, 45%, 43%, 41%, and 32% of the children, respectively. CD was diagnosed by biopsy in 20 of the 26 TGA-positive children who consented to a biopsy.CONCLUSIONS: Potential CD trigger(s) other than only gluten probably function before AGA-IgG emerges, i.e., ≥3 months earlier than the transglutaminase-associated antibodies appear. In a remarkable proportion of the children, antibodies disappear spontaneously suggesting that regulatory immune phenomena under favorable circumstances are able to extinguish incipient CD in genetically at-risk children even without exclusion of gluten from the diet.

Association of Human Bocavirus 1 Infection with Respiratory Disease in Childhood Follow-up Study, Finland

Since its discovery in 2005, human bocavirus type 1 has often been found in the upper airways of young children with respiratory disease. But is this virus the cause of the respiratory disease or just an innocent bystander? A unique study in Finland, which examined follow-up blood samples of 109 healthy children with no underlying illness starting at birth and until they were 13 years of age, found that acute bocavirus infection resulted in respiratory disease. All children had been infected by age 6. Most retained their antibodies to this virus; some lost them. Children who were later re-exposed to bocavirus did not get sick from this virus. Thus, human bocavirus type 1 is a major cause of respiratory disease in childhood.

Bacteroides dorei dominates gut microbiome prior to autoimmunity in Finnish children at high risk for type 1 diabetes

The incidence of the autoimmune disease, type 1 diabetes (T1D), has increased dramatically over the last half century in many developed countries and is particularly high in Finland and other Nordic countries. Along with genetic predisposition, environmental factors are thought to play a critical role in this increase. As with other autoimmune diseases, the gut microbiome is thought to play a potential role in controlling progression to T1D in children with high genetic risk, but we know little about how the gut microbiome develops in children with high genetic risk for T1D. In this study, the early development of the gut microbiomes of 76 children at high genetic risk for T1D was determined using high-throughput 16S rRNA gene sequencing. Stool samples from children born in the same hospital in Turku, Finland were collected at monthly intervals beginning at 4–6 months after birth until 2.2 years of age. Of those 76 children, 29 seroconverted to T1D-related autoimmunity (cases) including 22 who later developed T1D, the remaining 47 subjects remained healthy (controls). While several significant compositional differences in low abundant species prior to seroconversion were found, one highly abundant group composed of two closely related species, Bacteroides dorei and Bacteroides vulgatus, was significantly higher in cases compared to controls prior to seroconversion. Metagenomic sequencing of samples high in the abundance of the B. dorei/vulgatus group before seroconversion, as well as longer 16S rRNA sequencing identified this group as Bacteroides dorei. The abundance of B. dorei peaked at 7.6 months in cases, over 8 months prior to the appearance of the first islet autoantibody, suggesting that early changes in the microbiome may be useful for predicting T1D autoimmunity in genetically susceptible infants. The cause of increased B. dorei abundance in cases is not known but its timing appears to coincide with the introduction of solid food.

Clinical Features of Celiac Disease: A Prospective Birth Cohort

OBJECTIVES: To investigate clinical features of celiac disease (CD) and their association with risk factors for CD in a genetic risk birth cohort. METHODS: Children from 6 clinical centers in 4 countries positive for HLA-DR3-DQ2 or DR4-DQ8 were annually screened for tissue transglutaminase antibodies (tTGA) and assessed for symptoms by questionnaires. Associations of symptoms with anthropometrics, known risk factors for CD, tTGA levels, and mucosal lesions in those biopsied were examined. RESULTS: Of 6706 screened children, 914 developed persistent positive tTGA, 406 underwent biopsies, and 340 had CD. Compared with age-matched tTGA-negative children, those with persistent tTGA were more likely to have symptoms at 2 (34% vs 19%, P < .001) and 3 years of age (28% vs 19%, P = .009) but not at 4 years (27% vs 21%, NS). Z-scores for height, weight, and BMI did not differ between groups. In children with persistent tTGA, having ≥1 symptom was associated with family history of CD (odds ratio = 2.59, 95% confidence interval, 1.21–5.57) but not with age, gender, or HLA-DR3-DQ2 homozygosity. At seroconversion, tTGA levels were higher in symptomatic than asymptomatic children (P < .001), in those from CD families (P < .001), and in US participants (P < .001) but not associated with age, gender, or HLA genotype. tTGA levels correlated with severity of mucosal lesions both in symptomatic (r = 0.53, P < .001) and asymptomatic children (r = 0.22, P = .01). CONCLUSIONS: A majority of children detected with persistent tTGA in screenings are asymptomatic and have normal growth by age 4 years. tTGA levels correlate more strongly with severity of mucosal lesions in symptomatic as compared with asymptomatic children.

Cord Serum Lipidome in Prediction of Islet Autoimmunity and Type 1 Diabetes

Previous studies show that children who later progress to type 1 diabetes (T1D) have decreased preautoimmune concentrations of multiple phospholipids as compared with nonprogressors. It is still unclear whether these changes associate with development of β-cell autoimmunity or specifically with clinical T1D. Here, we studied umbilical cord serum lipidome in infants who later developed T1D (N = 33); infants who developed three or four (N = 31) islet autoantibodies, two (N = 31) islet autoantibodies, or one (N = 48) islet autoantibody during the follow-up; and controls (N = 143) matched for sex, HLA-DQB1 genotype, city of birth, and period of birth. The analyses of serum molecular lipids were performed using the established lipidomics platform based on ultra-performance liquid chromatography coupled to mass spectrometry. We found that T1D progressors are characterized by a distinct cord blood lipidomic profile that includes reduced major choline-containing phospholipids, including sphingomyelins and phosphatidylcholines. A molecular signature was developed comprising seven lipids that predicted high risk for progression to T1D with an odds ratio of 5.94 (95% CI, 1.07–17.50). Reduction in choline-containing phospholipids in cord blood therefore is specifically associated with progression to T1D but not with development of β-cell autoimmunity in general.

Age at Development of Type 1 Diabetes and Celiac Disease-Associated Antibodies and Clinical Disease in Genetically Susceptible Children Observed from Birth

OBJECTIVE To compare the ages and sequence in which antibodies associated with type 1 diabetes and celiac disease appear and overt diseases develop in children with an HLA-conferred susceptibility to both diseases. RESEARCH DESIGN AND METHODS We observed 2,052 children carrying genetic risks for both type 1 diabetes and celiac disease from birth until the median age of 5.7 years and analyzed diabetes- and celiac disease–associated antibodies in serum samples collected at 3- to 12-month intervals. Diabetes was confirmed by World Health Organization criteria and celiac disease by duodenal biopsies. RESULTS Altogether 342 children seroconverted to positivity for at least one diabetes-associated autoantibody and 88 to positivity for at least one celiac disease–associated antibody at the median ages of 3.0 and 1.5 years, respectively (P < 0.001). If only children with biochemically defined diabetes-associated autoantibodies against insulin, GAD, or IA-2A protein (n = 146) and children with tissue transglutaminase autoantibodies were compared (n = 86), the median seroconversion ages were 2.5 and 3.0 years (P = 0.011). Fifty-one children progressed to overt diabetes at 4.5 years and 44 children to celiac disease at 4.3 years (P = 0.257). Of the 19 children who developed both diabetes- and celiac disease–associated antibodies, 3 progressed to both diabetes and celiac disease. CONCLUSIONS Children with HLA-conferred susceptibility to type 1 diabetes and celiac disease develop celiac disease–associated antibodies mostly at a younger age or the same age at which they develop diabetes-associated autoantibodies. Clinical diabetes and celiac disease are commonly diagnosed at the same median age.

An Increase in Serum 25-Hydroxyvitamin D Concentrations Preceded a Plateau in Type 1 Diabetes Incidence in Finnish Children

Abstract Context In Finland the world-record for the highest incidence of type 1 diabetes has risen steeply over the past decades. However, after 2006 the incidence rate has plateaued. We showed earlier, that despite the strong genetic disease component, environmental factors are driving the increasing disease incidence. Objective Since vitamin D intake has increased considerably in the country since 2003, we analyzed how serum 25-hydroxyvitamin D (25[OH]D) concentration changed over time in healthy children, and the timely relation of these changes to disease incidence. Design, Setting and Participants The birth cohort of the Finnish Type 1 Diabetes Prediction and Prevention project was used to explore longitudinal changes in serum 25-hydroxyvitamin concentrations. The sampling period was limited to children born from 1994 to 2004, with serum samples collected during 1998–2006 in the Turku area, Southwest Finland (60 °N). Main Outcome Measure 25(OH)D concentrations were measured every 3–6 months from birth, ages ranging from 0.3 to 12.2 years (387 subjects, 5334 measurements). Results Serum 25(OH)D concentrations were markedly lower before 2003 than after (69.3 ± 1.0 nmol/L vs 84.9 ± 1.3 nmol/L, respectively, P < .001) in both genders. The mean difference between the periods was 15.7 ± 1.3 nmol/L (P < .001). Importantly, the frequency of children with low serum 25(OH)D levels (< 50 nmol/L) was reduced to almost half from 2003 (37.3% vs 69.9 %; P < .001). Similarly, severe vitamin D deficiency (<25 nmol/L) also decreased (2.7% vs 7.7%; P = .005). In addition, we detected higher 25(OH)D concentrations in young children (< 2 years) as compared to older children, which is explained by higher vitamin D intake in this group. Conclusions We provide evidence that an increase in circulating concentrations of 25(OH)D shows a delayed temporal association with leveling off of type 1 diabetes incidence in Finland after 2006.

Factors That Increase Risk of Celiac Disease Autoimmunity After a Gastrointestinal Infection in Early Life

Background & Aims Little is known about the pathogenic mechanisms of gluten immunogenicity in patients with celiac disease. We studied temporal associations between infections and the development of celiac disease autoimmunity, and examined effects of HLA alleles, rotavirus vaccination status, and infant feeding. Methods We monitored 6327 children in the United States and Europe carrying HLA risk genotypes for celiac disease from 1 to 4 years of age for presence of tissue transglutaminase autoantibodies (the definition of celiac disease autoimmunity), until March 31, 2015. Parental reports of gastrointestinal and respiratory infections were collected every third month from birth. We analyzed time‐varying relationships among reported infections, rotavirus vaccination status, time to first introduction of gluten, breastfeeding, and risk of celiac disease autoimmunity using proportional hazard models. Results We identified 13,881 gastrointestinal infectious episodes (GIE) and 79,816 respiratory infectious episodes. During the follow‐up period, 732 of 6327 (11.6%) children developed celiac disease autoimmunity. A GIE increased the risk of celiac disease autoimmunity within the following 3 months by 33% (hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.11–1.59). This risk increased 2‐fold among children born in winter and introduced to gluten before age 6 months (HR, 2.08; 95% CI, 1.46–2.98), and increased 10‐fold among children without HLA‐DQ2 alleles and breastfed for fewer than 4 months (HR, 9.76; 95% CI, 3.87–24.8). Risk of celiac disease autoimmunity was reduced in children vaccinated against rotavirus and introduced to gluten before age 6 months (HR, 0.57; 95% CI, 0.36–0.88). Conclusions Gastrointestinal infections increase the risk of celiac disease autoimmunity in children with genetic susceptibility to this autoimmune disorder. The risk is modified by HLA genotype, infant gluten consumption, breastfeeding, and rotavirus vaccination, indicating complex interactions among infections, genetic factors, and diet in the etiology of celiac disease in early childhood.

Reduced β-cell function in early preclinical type 1 diabetes

Objective We aimed to characterize insulin responses to i.v. glucose during the preclinical period of type 1 diabetes starting from the emergence of islet autoimmunity. Design and methods A large population-based cohort of children with HLA-conferred susceptibility to type 1 diabetes was observed from birth. During regular follow-up visits islet autoantibodies were analysed. We compared markers of glucose metabolism in sequential intravenous glucose tolerance tests between 210 children who were positive for multiple (≥2) islet autoantibodies and progressed to type 1 diabetes (progressors) and 192 children testing positive for classical islet-cell antibodies only and remained healthy (non-progressors). Results In the progressors, the first phase insulin response (FPIR) was decreased as early as 4–6 years before the diagnosis when compared to the non-progressors (P=0.001). The difference in FPIR between the progressors and non-progressors was significant (P<0.001) in all age groups, increasing with age (at 2 years: difference 50% (95% CI 28–75%) and at 10 years: difference 172% (95% CI 128–224%)). The area under the 10-min insulin curve showed a similar difference between the groups (P<0.001; at 2 years: difference 36% (95% CI 17–58%) and at 10 years: difference 186% (95% CI 143–237%)). Insulin sensitivity did not differ between the groups. Conclusions FPIR is decreased several years before the diagnosis of type 1 diabetes, implying an intrinsic defect in β-cell mass and/or function.