The feasibility of existing JADAS10 cut-off values in clinical practice: a study of data from The Finnish Rheumatology Quality Register.

BACKGROUND: The ten-joint juvenile arthritis disease activity score (JADAS10) is designed to measure the level of disease activity in non-systemic juvenile idiopathic arthritis by providing a single numeric score. The clinical JADAS10 (cJADAS10) is a modification of the JADAS10 that excludes erythrocyte sedimentation rate (ESR). Three different sets of JADAS10/cJADAS10 cut-offs for disease activity states have been published, i.e., the Backström, Consolaro, and Trincianti cut-offs. The objective of this study was to investigate the performance of existing JADAS10 cut-offs in real-life settings using patient data from The Finnish Rheumatology Quality Register (FinRheuma). METHODS: Data were collected from the FinRheuma register. The proportion of patients with an active joint count (AJC) above zero when classified as being in clinically inactive disease (CID) or low disease activity (LDA) groups according to existing JADAS10/cJADAS10 cut-off levels were analyzed. RESULTS: A significantly larger proportion of the patients classified as being in CID had an AJC > 0 when using the JADAS10/cJADAS10 cut-offs by Trincianti et al. compared to those for the other cut-offs. In the LDA group, a significantly larger proportion of the polyarticular patients (35%/29%) had an AJC of two when Trincianti JADAS10/cJADAS10 cut-offs were used compared with when Backström (11%/10%) and Consolaro (7%/3%) JADAS10/cJADAS10 cut-offs were used. CONCLUSIONS: We found the cut-offs proposed by Consolaro et al. to be the most feasible, since these cut-off levels for CID do not result in the misclassification of active disease as remission, and the proportion of patients with AJC > 1 in the LDA group is lowest using these cut-offs.

Faecal microbiome in new-onset juvenile idiopathic arthritis.

Alterations in the intestinal microbial flora have been linked with autoimmune diseases. Our objective was to analyse the composition of the faecal microbiome of children with new-onset juvenile idiopathic arthritis (JIA) compared to healthy controls, and to identify specific gut bacteria associated with JIA. Stool samples from patients were taken at the time of diagnosis of JIA. The microbiome profiles of samples of 30 children with JIA (mean age 6.2 years, 22 girls) were analysed with 16S region-based sequencing profiling and compared to the stool samples of healthy controls (n = 27, mean age 5.4 years, 18 girls). The proportion of bacteria belonging to the phylum Firmicutes was significantly lower in children with JIA [21 % (95 % confident interval [CI]: 17-25 %)] compared to controls [33 % (95 % CI: 26-41 %), p = 0.009]. Bacteria belonging to Bacteroidetes were significantly more abundant in JIA [78 % (95 % CI: 74-82 %)] than in control samples [65 % (95 % CI: 57-73 %), p = 0.008]. Shared operational taxonomic units (OTUs) between the groups revealed that genera Actinobacteria and Fusobacteria were present only in JIA patients and Lentisphaerae only in controls. In summary, faecal flora in JIA is characterised by a low level of Firmicutes and an abundance of Bacteroidetes, resembling the aberration reported in type 1 diabetes. We suggest that alterations in the intestinal microbial flora may challenge the mucosal immune system of genetically susceptible subjects predisposing to local proinflammatory cascades, thus contributing to the development of JIA.

Decreased expression of protease inhibitor 9, a granzyme B inhibitor, in celiac disease: a potential mechanism in enterocyte destruction and villous atrophy.

The objective of this study was to assess the expression of protease inhibitor 9, a granzyme B inhibitor, in human small intestine, and to evaluate its cytoprotective role in the celiac disease of children. Twelve subjects with untreated celiac disease and thirteen healthy controls were examined by endoscopy. The expression of protease inhibitor 9 was analyzed immunohistochemically from duodenal biopsies and compared to granzyme B expression, apoptosis rate, number of intraepithelial lymphocytes and villus and crypt height data from the biopsies. We discovered that protease inhibitor 9 is expressed in the cytoplasm of the duodenal epithelial cells in the majority of cases. The enterocyte expression of protease inhibitor 9 was lower in celiac disease patients than in controls. Protease inhibitor 9 expression also showed a negative correlation with the number of apoptotic cells, overall density of granzyme B expressing intraepithelial lymphocytes, the height of the crypts and the severity of villous atrophy in duodenum. Therefore, we conclude that the protease inhibitor 9 is constantly expressed in the enterocytes of normal duodenum and the expression is decreased in celiac disease. These findings suggest that protease inhibitor 9 has a role in duodenal homeostasis and in the protection of enterocytes from misdirected granzyme B. Indeed, observed associations of lowered protease inhibitor 9 expression together with increased granzyme B expression, apoptosis rate and severity of villous atrophy suggest that impaired balance between granzyme B mediated cytotoxicity and its inhibition by protease inhibitor 9 forms an important factor in the pathogenesis of villous atrophy in celiac disease.

Altered expression of intestinal human leucocyte antigen D-related and immune signalling molecules in juvenile idiopathic arthritis.

We aimed to study intestinal immune activation status in juvenile idiopathic arthritis (JIA) by assessing intestinal human leucocyte antigen (HLA) class II expression and the mRNA expression levels of the pro- and anti-inflammatory mediators and pattern recognition receptors. HLA-D-related (HLA-DR) expression was assessed using immunohistochemical staining of frozen sections in 11 children with JIA and 17 controls. The gene expression levels of the anti- and proinflammatory cytokines, lymphocyte recognition receptors and pattern recognition receptors were studied with reverse transcription-polymerase chain reaction (RT-PCR) in 14 children with JIA and 12 controls. All subjects had various gastrointestinal (GI) symptoms indicating endoscopic examinations, but eventually were not diagnosed with GI disease. In JIA patients, the expression of HLA-DR was increased in the crypt epithelial cells and in the epithelial basement membrane of the ileum when compared with the controls. Positive HLA-DR staining in the ileal mucosa was associated with the presence of high clinical disease activity of JIA and low mRNA expression of anti-inflammatory mediators, such as forkhead box protein P3 (FoxP3), glucocorticoid-induced tumour necrosis factor receptor-related protein (GITR) and transforming growth factor (TGF)-beta. Low ileal expression of interleukin (IL)-10, TGF-ß, FoxP3, Toll-like receptor 2 (TLR-2) and TLR-4 transcripts correlated significantly with a high clinical disease activity in the JIA patients. The increased HLA-DR expression suggests enhanced intestinal antigen presentation in JIA. A correlation between clinical disease activity and low gene expression of tolerogenic mediators in the ileum supports the hypothesis that a link exists between the gut immune system and JIA.

Increase of duodenal and ileal mucosal cytotoxic lymphocytes in juvenile idiopathic arthritis.

OBJECTIVE: Intestinal gamma/delta- intraepithelial lymphocytes (IEL) have increased in children with juvenile idiopathic arthritis (JIA). To further characterise intestinal immune activation in these children, we have quantitated cytotoxic lymphocytes in intestinal mucosa. METHODS: We studied 23 children with JIA suffering from gastrointestinal symptoms with gastroduodenoscopy and colonoscopy. The control children (n=20) had GI-symptoms but eventually shown not to have any significant gastrointestinal disease. Granzyme A (GrA) and Granzyme B (GrB) expressing lymphocytes in the epithelium and lamina propria were counted in immunostained sections of ileal and duodenal biopsies. RESULTS: The number of GrB expressing IELs was increased in duodenal mucosa in patients with JIA. In the ileum the number of both GrB and GrA positive IELs was similarly increased. No significant differences in the counts of the lamina propria GrA or GrB expressing cells were observed. Granzyme expression was not associated with the duration or with the severity of the disease, or with medication. CONCLUSIONS: These observations suggest that lymphocyte cytotoxicity is abnormally increased in the intestinal mucosa in JIA. Since a similar pattern of activation has been seen in food allergy and celiac disease, we speculate that some luminal, possibly a nutritional factor may be involved in JIA as well. Further studies are needed to see whether cytotoxic activation plays any role in the pathogenesis of JIA.

Heat shock protein expression is low in intestinal mucosa in juvenile idiopathic arthritis: a defect in immunoregulation?

OBJECTIVES: Heat shock proteins (HSPs) are involved in the regulation of inflammation and in the maintenance of mucosal integrity. Their altered expression may be a marker of mucosal inflammation and also contribute to tissue injury. The small intestinal mucosa in children with juvenile idiopathic arthritis (JIA) shows signs of intestinal immune activation, such as increased intraepithelial cytotoxic lymphocyte counts. To further evaluate the characteristics of this immune activation in JIA, we have studied the expression of several HSPs, major histocompatibility complex (MHC) class I-related chain A (MICA), and the heat shock transcription factor 1 (HSF1) in intestinal biopsies from children with JIA. METHODS: We studied 15 patients with JIA. Controls included 13 children without JIA, studied for various gastrointestinal (GI) symptoms, but eventually shown not to have any GI disease. The subjects were examined by endoscopy. The expression of HSP60, HSP70, MICA, and HSF1 was analysed in ileal and duodenal biopsies by using immunohistochemistry. RESULTS: The expression levels of HSP60, MICA, and HSF1 were significantly lower in the duodenal epithelium in the JIA patients compared to the controls. MICA and HSF1 also showed lower expression in the ileal epithelium. The expression of HSP70 did not differ between the groups. CONCLUSIONS: The downregulation of HSP60, MICA, and HSF1 in small intestinal mucosa may indicate that intestinal epithelial cells show immune aberration in JIA. We speculate that the low heat shock response may play a role in the pathogenesis of JIA, interfering with mucosal integrity and local intestinal immunoregulation.

Drug survival of the first and second course of anti-tumour necrosis factor agents in juvenile idiopathic arthritis.

OBJECTIVES: To evaluate drug survival (continuation rates on drug) of anti-tumour necrosis factor (TNF) agents in juvenile idiopathic arthritis (JIA) and predictors for treatment discontinuation. METHODS: A retrospective observational study on JIA patients taking etanercept (n = 105) or infliximab (n = 104) with at least one year follow-up. Kaplan-Meier curves and log-rank statistics were used to compare treatments and a proportional hazards model to assess risk factors for discontinuation. RESULTS: Etanercept versus infliximab treatment survival at 12 months was 83% versus 80%, at 24 months 68% versus 68%, at 36 months 64% versus 53%, at 48 months 61% versus 48% (p = 0.194), respectively. Reasons for discontinuing the first biological treatment were inefficacy (etanercept 28% vs infliximab 20%, p = 0.445), adverse events (7% vs 22%, p = 0.002) or inactive disease (10% vs 16%, p = 0.068). Women (hazard ratio (HR) 2.8, 95% CI 1.3 to 5.8), patients with systemic JIA (HR 7.8, 95% CI 1.7 to 34.9) or those taking infliximab (HR 2.0, 95% CI 1.2 to 3.3) were at higher risk of treatment discontinuation. One-third of the patients were switched to the second anti-TNF therapy, which was discontinued less frequently than the first. At 12 months treatment survival of etanercept was 60%, infliximab 58% and adalimumab 66% as the second-line anti-TNF therapy. CONCLUSIONS: Although infliximab was discontinued more often than etanercept because of adverse events, during a 48-month follow-up the overall treatment survival of etanercept and infliximab as the first biological agent in JIA was comparable. A switch from one anti-TNF agent to another appears a reasonable therapeutic option.

Intestinal immune activation in juvenile idiopathic arthritis and connective tissue disease.

OBJECTIVES: To examine the prevalence of immune activation in gastrointestinal (GI) mucosa in children with juvenile idiopathic arthritis (JIA) or connective tissue disease (CTD). STUDY DESIGN: We studied 27 children (15 girls, mean age 9.8+/-4.8 years) with JIA/CTD and GI symptoms, including nine with oligoarthritis, nine with polyarthritis, two with systemic arthritis, three with enthesitis-related arthritis, and four with various CTDs. The control group consists of 54 children (31 girls, mean age 11.3+/-6.3 years) with GI symptoms but shown to have no significant GI or rheumatoid disorder. The subjects were examined by gastroduodenoscopy (22 patients, 50 controls) and colonoscopy (23 patients, 16 controls). Intraepithelial CD3+, alpha/beta+, and gamma/delta+ lymphocytes were counted from duodenal and ileal biopsies. RESULTS: Five patients with JIA/CTD (19%) had ulcerative colitis. Lymphoid nodular hyperplasia (LNH) was more common in the patients [74% (20/27)] than in the controls [16% (8/50), p = 0.001], as well in the duodenal bulb [29% (7/24) vs. 10% (5/50)], terminal ileum [74% (14/19) vs. 38% (5/13)], and the colon [50% (11/22) vs. 14% (2/14)]. In the duodenum, CD3, alpha/beta+, and gamma/delta+ lymphocytes counts were higher in JIA/CTD (p<0.05). In the ileum, gamma/delta+ cell numbers had increased in JIA/CTD (p<0.05). Either LNH, increased gamma/delta+ count, or both were more common in JIA/CTD [89% (24/27)] than in the controls [13% (7/54), p<0.0001]. CONCLUSIONS: The majority of children suffering from JIA or CTD with GI symptoms show abnormalities consistent with activation of the intestinal immune system. The aetiology of this reaction remains unknown, but similar features are seen in delayed-type food allergy.

Impact of anti-TNF treatment on growth in severe juvenile idiopathic arthritis.

OBJECTIVES: To evaluate the impact of anti-tumour necrosis factor (TNF) treatment on growth and to identify the predictors for the change in growth in severe juvenile idiopathic arthritis (JIA). METHODS: Data from 71 JIA patients (43 on etanercept, 28 on infliximab) were reviewed two years before and two years on the anti-TNF treatment. The patients had polyarticular disease course (48 polyarthritis, 19 extended oligoarthritis, two systemic arthritis, and two enthesitis related arthritis). At the initiation of the anti-TNF treatment, their mean age was 9.6 years and the mean duration of JIA, 5.7 years. RESULTS: In the patients with delayed growth before anti-TNF treatment (n = 53), the growth velocity, measured as the change in height standard deviation score, accelerated +0.45 (95% confidence interval, 0.33 to 0.56) (p<0.001) during the anti-TNF treatment. In the patients with normal or accelerated growth before anti-TNF treatment (n = 18), the change in growth velocity was +0.05 (0.07 to 0.16) (p = 0.39). At two years on anti-TNF treatment, the growth velocity between these two groups was similar. No difference was found between the patients treated with etanercept or infliximab. A decelerating growth rate before the anti-TNF treatment was the strongest predictor for the observed increase in the growth velocity. The change in the inflammatory activity remained a significant predictor of the growth velocity even after the decrease in glucocorticoid dose was taken into account. CONCLUSIONS: In the treatment of polyarticular JIA, the anti-TNF treatment not only suppresses inflammation but also restores growth velocity.

Infliximab or etanercept in the treatment of children with refractory juvenile idiopathic arthritis: an open label study.

OBJECTIVE: To study infliximab and etanercept in the treatment of refractory juvenile idiopathic arthritis (JIA). METHODS: In a non-randomised, prospective, open label study, 24 patients (mean age 10.2 years, range 3.3-16.3) with polyarticular JIA were treated with either infliximab (n=14) or etanercept (n=10). The patients had had active polyarthritis for at least one year and standard treatment had failed. Anti-tumour necrosis factor (TNF) treatment was added to the current drug treatment. Infliximab (3-4 mg/kg) was given intravenously at weeks 0, 2, and 6, and thereafter at 4 to 8 week intervals. Etanercept (0.4 mg/kg) was given subcutaneously twice a week. Improvement of the patients was assessed at 3, 6, and 12 months according to established JIA response criteria. RESULTS: In intention to treat analyses, patients in both treatment groups improved significantly. ACR Paediatric 50 was achieved at 3, 6, and 12 months by 9/10 (90%), 8/9 (89%), and 8/9 (89%) patients with etanercept and by 8/12 (67%), 10/12 (83%), and 7/9 (78%) with infliximab, respectively. At 12 months, ACR Paediatric 75 was achieved by 67% of patients in both treatment groups. Five withdrawals due to adverse effects or lack of efficacy occurred in the infliximab group and one due to lack of compliance in the etanercept group. CONCLUSION: In this open label clinical study of active JIA, both infliximab and etanercept provided a significant rapid and sustained reduction in disease activity. Adequately powered randomised controlled trials are needed to elucidate the long term safety and efficacy of TNF modulators in the treatment of JIA.

No evidence of abnormal regulation of antibody response to coxsackievirus B4 antigen in prediabetic children.

Enterovirus infections are a potential environmental trigger of the autoimmune process leading to clinical type 1 diabetes. It has been suggested that the risk of virus-induced beta-cell damage might be connected with a defect in humoral immune responsiveness to enteroviruses. In the present study we assessed whether such a defect in IgG responsiveness to coxsackievirus B4 antigen existed in young children who developed diabetes-associated autoantibodies during prospective observation from birth until the age of 18 months. IgG levels and maturation of antibody avidity were analysed in 21 children with autoantibodies and 41 control children who had experienced an equal number of enterovirus infections and were additionally matched for age, sex and HLA-DQB1 risk alleles for type 1 diabetes but had not produced diabetes-associated autoantibodies. IgG levels to coxsackievirus B4 were high in cord serum reflecting the presence of maternal antibodies. Mean IgG levels gradually decreased but began to increase after the age of 6 months, showing no significant difference between autoantibody positive and control children. The avidity of antibodies was strong in cord serum and decreased gradually during the first year of life when maternal antibodies disappeared. The avidity indices, which varied considerably from child to child, did not differ between the autoantibody-positive and -negative subjects. In conclusion, our data suggest that children affected by a beta-cell damaging autoimmune process show normal responses to coxsackievirus B4 antigens.

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.

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.

Stability of autoantibodies and their relation to genetic and metabolic markers of Type I diabetes in initially unaffected schoolchildren.

AIMS/HYPOTHESIS: To study temporal changes in positivity for autoantibodies associated with Type I (insulin-dependent) diabetes mellitus and the relations between these antibodies, HLA-DQB1-risk markers and first-phase insulin response (FPIR) in non-diabetic schoolchildren. METHODS: The stability of the antibody status over 2 years was assessed in 104 schoolchildren initially positive for islet cell antibodies (ICA) or antibodies to the 65,000 M(r) isoform of the glutamic acid decarboxylase (GADA) or both and in 104 antibody-negative control children matched for sex, age and place of residence. All children were also studied for their first-phase insulin response and HLA-DQB1 alleles on the second occasion. RESULTS: On the second occasion 3 of the 98 initially ICA-positive children, 3/13 of those positive for antibodies to the IA-2 protein (IA-2A), 1/17 GADA-positive and 2/7 of those positive for insulin autoantibodies (IAA) tested negative for these antibodies. Children with IA-2A, GADA, IAA and multiple (> or = 2) antibodies had significantly lower first-phase insulin responses than the control children. In contrast, these responses did not differ between subjects with and without specific HLA-DQB1-risk alleles or genotypes. Of the six subjects with a considerably reduced first-phase insulin response three had multiple antibodies on both occasions but none of them had a DQB1 genotype conferring increased diabetes risk. Two subjects progressed to Type I diabetes within 3.4 years of follow-up, both of them having multiple antibodies and a considerably reduced first-phase insulin response but neither of them having a DQB1-risk genotype. CONCLUSIONS/INTERPRETATION: Positivity for diabetes-associated autoantibodies is a relatively stable phenomenon in unaffected schoolchildren, although conversion to seronegativity can occur occasionally. Our observations also indicate that DQB1 alleles associated with decreased susceptibility to Type I diabetes do not protect from impaired beta-cell function or from progression to overt disease in initially unaffected schoolchildren.

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.

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.

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.

Disease-associated autoantibodies and HLA-DQB1 genotypes in children with newly diagnosed insulin-dependent diabetes mellitus (IDDM). The Childhood Diabetes in Finland Study Group.

The possible relation between HLA-DQ genotypes and both frequencies and levels of autoantibodies associated with IDDM was assessed by examining HLA-DQB1 alleles and antibodies to islet cells (ICA), insulin (IAA), glutamic acid decarboxylase (GADA) and the protein tyrosine phosphatase-related IA-2 molecule (IA-2A) in 631 newly diagnosed diabetic children under the age of 15 years. ICA were found in 530 children (84.0%), while close to half of the subjects (n = 307; 48.7%) tested positive for IAA. GADA were detected in 461 index cases (73.1%), with a higher frequency in those older than 10 years (78.9% versus 69.2% in the younger ones; P = 0.006). More than 85% of the children (n = 541; 85.7%) tested positive for IA-2A. Altogether there were only 11 children (1.7%) who had no detectable autoantibodies at diagnosis. There were no differences in the prevalence of ICA or GADA between four groups formed according to their HLA-DQB1 genotype (DQB1*0302/02, *0302/X (X = other than *02), *02/Y (Y = other than *0302) and other DQB1 genotypes). The children with the *0302/X genotype had a higher frequency of IA-2A and IAA than those carrying the *02/Y genotype (93.8% versus 67.3%, P < 0.001; and 49.0% versus 33.6%, P = 0.002, respectively). The children with the *02/Y genotype had the highest GADA levels (median 36.2 relative units (RU) versus 14.9 RU in those with *0302/X; P = 0.005). Serum levels of IA-2A and IAA were increased among subjects carrying the *0302/X genotype (median 76.1 RU versus 1.6 RU, P = 0.001; and 50 nU/ml versus 36 nU/ml, P = 0.004) compared with those positive for *02/Y. Only three out of 11 subjects homozygous for *02 (27.3%) tested positive for IA-2A, and they had particularly low IA-2A (median 0.23 RU versus 47.6 RU in the other subjects; P < 0.001). The distribution of HLA-DQB1 genotypes among autoantibody-negative children was similar to that in the other patients. These results show that DQB1*0302, the most important single IDDM susceptibility allele, is associated with a strong antibody response to IA-2 and insulin, while GAD-specific humoral autoimmunity is linked to the *02 allele, in common with a series of other autoimmune diseases as well as IDDM. We suggest that IA-2A may represent beta cell-specific autoimmunity, while GADA may represent a propensity to general autoimmunity.