Biomedical subjects

J Ilonen

Publications and source records attributed to J Ilonen.

At least 73 records · Page 4Linked to original sources

PubMed2000

Autoimmunity to glutamic acid decarboxylase in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED).

Antibodies to glutamic acid decarboxylase (GAD) occur frequently in patients with APECED, although clinical insulin-dependent diabetes mellitus (IDDM) is seen only in a subgroup of the patients. We studied the cellular immunity to GAD, antibodies to GAD and their association with the HLA DQB1 risk alleles for IDDM in patients with APECED. Proliferation responses to GAD were enhanced in the patients with APECED when compared with the control subjects (P = 0.004), but autoimmunity to GAD was not associated with IDDM in APECED. The levels of interferon-gamma (IFN-gamma) secreted by GAD-stimulated T cells were higher in the patients than in control subjects (P = 0. 001). A negative correlation (r = - 0.436, P = 0.03) existed between the antibody levels and the stimulation indices (SIs) to GAD. In 14 non-diabetic patients no difference in insulin secretion was observed in intravenous glucose tolerance test (IVGTT) between the patients with and without T cell reactivity to GAD. We conclude that cellular immunity to GAD detected as T cell proliferation response to GAD or IFN-gamma secretion by GAD-stimulated T cells was frequent in patients with APECED (69%) and was not restricted to the patients with clinically detectable beta-cell damage.

Adolescent↗

PubMed2000

Geographical differences within Finland in the frequency of HLA-DQ genotypes associated with type 1 diabetes susceptibility. The Childhood Diabetes in Finland Study Group.

Geographical variations in the HLA-DQ genotypes associated with risk for type 1 diabetes were evaluated in Finland. Samples of 280 diabetic children diagnosed in Turku (south-west of the country) and 405 in Oulu (north of the country) were studied as well as a series of 14 096 and 10 016 newborns collected from the same hospitals. There were no major differences in the risk or protection conferred by various HLA-DQB1 genotypes between south-western and northern parts of the country when genotypes of children with type 1 diabetes from these two centres were compared with those of newborns, representing the background populations. However, the distribution of various genotypes was different, both in diabetic children and in newborns, when compared between the two regions (P < 0.0001, chi2 test). These differences reflected the allele frequencies in newborn cohorts in which HLA-DQB1*02 and DQB1*0301 were found more often in Turku and DQB1*0302 more often in Oulu (P < 0.0001 for all differences). Similar types of differences were detected when children who were diagnosed as having diabetes during the national 'Childhood Diabetes in Finland' (DiMe) study between the years 1986-1989 were compared according to their residence. The observed differences in genotype and allele frequencies demonstrate the heterogeneity for HLA alleles even in a population that is generally regarded as highly homogeneous. These differences also affect the sensitivity and efficiency of the screening programme used for identifying infants with genetic susceptibility to IDDM in the ongoing Finnish Diabetes Prediction and Prevention Study.

Adolescent↗

PubMed2000

Prolonged arthritis associated with sindbis-related (Pogosta) virus infection.

OBJECTIVE: A follow-up study of musculoskeletal symptoms after Pogosta virus infection. METHODS: Twenty-six patients with earlier serologically confirmed Pogosta disease were examined. Ultrasonography of affected joints was performed in patients who had chronic musculoskeletal symptoms. Serum antibodies against Sindbis virus were determined. The patients were typed for HLA-DR and B27. Efforts were made using the polymerase chain reaction to demonstrate the virus. RESULTS: Only 50% of the patients were symptomless 2.5 yr after onset of Pogosta disease. Three patients had fibromyalgia, six had occasional arthralgia and two had chronic arthritis. CONCLUSIONS: The epidemiology of Pogosta disease is changing and practitioners should be better aware of it. Pogosta virus infection may lead to chronic musculoskeletal discomfort and arthritis.

Adolescent↗

PubMed2000

Immunogenetic differences between patients with familial and non-familial rheumatoid arthritis.

OBJECTIVE: To search for possible immunogenetic differencies between the patients with familial and non-familial rheumatoid arthritis (RA). METHODS: The study compared 129 familial RA patients with 217 non-familial patients for the frequencies of HLA-DR antigens including DR4 subtypes, DR4-DQB1*0301 and DR4-DQB1*0302 haplotypes and HLA-B27 antigen as well as the age of disease onset and existence of rheumatoid factor or joint erosions. RESULTS: Two major differences between familial and non-familial groups were found: firstly, familial RA patients had increased frequency of HLA-DR4 as compared with the non-familial RA group (68.2 v. 54.8%; p = 0.019). Secondly, the mean age at onset of RA was significantly lower in the familial than in the sporadic RA patients (42.0 v. 46.5 years; p = 0.0020) and the difference still remained when the DR4 positive and negative subgroups were compared separately. CONCLUSION: These results confirm the more prominent association with HLA-DR4 in familial than in the non-familial cases and suggest that accumulation of HLA risk genes may, at least partly, explain the familial occurrence of the disease. Other susceptibility genes may also be concentrated in multiplex case families as suggested by an earlier age at the onset of RA in both HLA-DR4 positive and negative familial patients.

Adolescent↗

PubMed2000

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.

Adolescent↗

PubMed2000

Transient but not permanent neonatal diabetes mellitus is associated with paternal uniparental isodisomy of chromosome 6.

OBJECTIVES: The factors determining the pathogenesis of transient and permanent neonatal diabetes mellitus are poorly characterized. The purpose of this study was to examine the role of chromosome 6 in the pathogenesis of neonatal diabetes mellitus and to detect differences between these 2 phenotypes. METHODS: Microsatellite markers (D6S334, D6S286, D6S310, D6S308, D6S292, D6S311, and D6S403) and human leukocyte antigen DQ alleles were examined using polymerase chain reaction and DNA fragment electrophoresis in 3 patients with transient and 3 patients with permanent neonatal diabetes mellitus. Humoral markers of islet cell autoimmunity and clinical characteristics were analyzed in the 2 groups. RESULTS: A patient with transient neonatal diabetes mellitus (TND) and macroglossia carrying paternal uniparental isodisomy (UPD) of chromosome 6 has been identified. The isodisomy affected the whole chromosome; no maternal chromosome 6 sequences were detected. The permanent neonatal diabetes mellitus cases and the other 2 cases with TND did not have UPD. None of the patients had high-risk type 1 diabetes human leukocyte antigen DQ alleles and most infants were negative for islet cell-specific autoantibodies indicating that none of the 2 forms of neonatal diabetes mellitus is likely to be of autoimmune origin. An association of TND and persistent granulocytopenia is described for the first time. CONCLUSIONS: We propose that transient and permanent forms of neonatal diabetes mellitus have different genetic background and represent different disease entities. TND is associated with UPD of chromosome 6 suggesting that an imprinted gene on chromosome 6 is responsible for this phenotype. It seems that 2 copies of the paternal allele are necessary for the development of TND; therefore, it is likely that overexpression of a putative gene located on chromosome 6 alters pancreatic beta-cell maturation and insulin secretion.

Chromosomes, Human, Pair 6↗

PubMed2000

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.

Alleles↗

PubMed2000

Effect of cow's milk exposure and maternal type 1 diabetes on cellular and humoral immunization to dietary insulin in infants at genetic risk for type 1 diabetes. Finnish Trial to Reduce IDDM in the Genetically at Risk Study Group.

Type 1 diabetes is considered to be a T-cell-mediated autoimmune disease in which insulin-producing beta-cells are destroyed. Immunity to insulin has been suggested to be one of the primary autoimmune mechanisms leading to islet cell destruction. We have previously shown that the first immunization to insulin occurs by exposure to bovine insulin (BI) in cow's milk (CM) formula. In this study, we analyzed the development of insulin-specific T-cell responses by proliferation test, emergence of insulin-binding antibodies by enzyme immunoassay, and insulin autoantibodies by radioimmunoassay in relation to CM exposure and family history of type 1 diabetes in infants with a first-degree relative with type 1 diabetes and increased genetic risk for the disease. The infants were randomized to receive either an adapted CM-based formula or a hydrolyzed casein (HC)-based formula after breast-feeding for the first 6-8 months of life. At the age of 3 months, both cellular and humoral responses to BI were higher in infants exposed to CM formula than in infants fully breast-fed (P = 0.015 and P = 0.007). IgG antibodies to BI were higher in infants who received CM formula than in infants who received HC formula at 3 months of age (P = 0.01), but no difference in T-cell responses was seen between the groups. T-cell responses to BI at 9 months of age (P = 0.05) and to human insulin at 12 (P = 0.014) and 24 months of age (P = 0.009) as well as IgG antibodies to BI at 24 months of age (P = 0.05) were lower in children with a diabetic mother than in children with a diabetic father or a sibling, suggesting possible tolerization to insulin by maternal insulin therapy. The priming of insulin-specific humoral and T-cell immunity occurs in early infancy by dietary insulin, and this phenomenon is influenced by maternal type 1 diabetes.

Animals↗

PubMed2000

Non-class II HLA gene associated with type 1 diabetes maps to the 240-kb region near HLA-B.

Several studies provide evidence that in addition to the DQ-DR genes, HLA contains another uncharacterized gene or genes associated with type 1 diabetes. Our aim was to investigate the effect of this gene independently of the DQ-DR genes and to localize it with a matched case-control study. More than 1,400 patients and 30,000 control individuals from Finland were studied. They were first genotyped for the selected alleles of the HLA-DQB1, -DQA1, and -DRB1 genes. For the DR3/4(0404) genotype, 75 patients and 181 control subjects were stratified, and 241 patients and 354 controls were stratified for the DR3/4(0401) genotype. Ten microsatellite markers in the HLA class III and I regions (D6S273, TNFa, C12A, STR MICA, MIB, C125, C143, C245, C3211, and MOGc) and selected alleles of the HLA-A and HLA-B genes were studied. In the DR3/4(0404)-stratified group, we found that markers located between C12A and C143 near the HLA-B gene confer a strong additional diabetes association. This was confirmed by the population differentiation test in both DR3/4(0404)- and DR3/4(0401)-stratified groups. Our data indicate that an additional gene associated with type 1 diabetes is located in the 240-kb region near HLA-B. We excluded STR MICA polymorphism as a mutation responsible for diabetes association.

Adolescent↗

PubMed2000

Cow's milk consumption, HLA-DQB1 genotype, and type 1 diabetes: a nested case-control study of siblings of children with diabetes. Childhood diabetes in Finland study group.

The evidence for the putative role of cow's milk in the development of type 1 diabetes is controversial. We studied infant feeding patterns and childhood diet by structured questionnaire (n = 725) and HLA-DQB1 genotype by a polymerase chain reaction-based method (n = 556) in siblings of affected children and followed them for clinical type 1 diabetes. In a nested case-control design in a population who had both dietary and genetic data available, we selected as cases those siblings who progressed to clinical diabetes during the follow-up period (n = 33). For each case, we chose as matched control subjects siblings who fulfilled the following criteria: same sex, age within 1 year, not from the same family, the start of the follow-up within 6 months of that of the respective case, and being at risk for type 1 diabetes at the time the case presented with that disease (n = 254). The median follow-up time was 9.7 years (range 0.2-11.3). Early age at introduction of cow's milk supplements was not significantly associated with progression to clinical type 1 diabetes (relative risk adjusted for matching factors, maternal education, maternal and child's ages, childhood milk consumption, and genetic susceptibility markers was 1.60 [95% CI 0.5-5.1]). The estimated relative risk of childhood milk consumption for progression to type 1 diabetes was 5.37 (1.6-18.4) when adjusted for the matching and aforementioned sociodemographic factors, age at introduction of supplementary milk feeding, as well as for genetic susceptibility markers. In conclusion, our results provide support for the hypothesis that high consumption of cow's milk during childhood can be diabetogenic in siblings of children with type 1 diabetes. However, further studies are needed to assess the possible interaction between genetic disease susceptibility and dietary exposures in the development of this disease.

Adolescent↗

PubMed2000

T-cell responses to enterovirus antigens in children with type 1 diabetes.

Enterovirus infections, implicated in the pathogenesis of type 1 diabetes in a number of studies, may precipitate the symptoms of clinical diabetes and play a role in the initiation of the beta-cell damaging process. The aim of this study was to evaluate whether cellular immune responses to enterovirus antigens are abnormal in children with type 1 diabetes. Lymphocyte proliferation responses to enterovirus antigens were analyzed in 41 children with new-onset type 1 diabetes, 23 children with type 1 diabetes for 4-72 months, and healthy control children in subgroups matched for HLA-DQB1 risk alleles, sex, and age. Children with diabetes for 4-72 months more often had T-cell responses to the Coxsackievirus B4-infected cell lysate antigen than children with new-onset diabetes (P < 0.01) or control children (P < 0.01). Responses to recombinant nonstructural protein 2C of Coxsackievirus B4 were also more frequent in children with type 1 diabetes for 4-72 months when compared with control subjects (P = 0.03), whereas the responses to purified Coxsackievirus B4 and recombinant VP0 protein, which did not contain nonstructural proteins, did not differ. These data suggest that T-cell responses to Coxsackievirus B4 proteins and particularly to the antigens containing the nonstructural proteins of the virus are increased in children with type 1 diabetes after the onset of the disease. However, in children with new-onset diabetes, responses were normal or even decreased. This phenomenon was specific for enteroviruses and could be caused by trapping of enterovirus-specific T-cells in the pancreas.

Age of Onset↗

PubMed2000

Enterovirus infection as a risk factor for beta-cell autoimmunity in a prospectively observed birth cohort: the Finnish Diabetes Prediction and Prevention Study.

Previous studies suggest that enterovirus infections may initiate and accelerate beta-cell damage years before the clinical manifestation of type 1 diabetes. We have now analyzed the role of enterovirus infections in the initiation of autoimmunity in children who have tested positive for diabetes-associated autoantibodies in a prospective study starting at birth (the Finnish Diabetes Prediction and Prevention Study). The frequency of enterovirus infections was studied using both serology and testing for the presence of enterovirus RNA in the sera of 21 children who developed and retained autoantibodies and in 104 control subjects chosen from the same study cohort and matched for the time of birth, sex, and HLA alleles determining genetic diabetes susceptibility. Sample intervals were taken as basic units of follow-up, to which the observed number of infections was adjusted. Enterovirus infections were detected in 26% of sample intervals in the case subjects and in 18% of the sample intervals in the control children (P = 0.03). A temporal relationship between enterovirus infections and the induction of autoimmunity was found; enterovirus infections were detected in 57% of the case subjects during a 6-month follow-up period preceding the first appearance of autoantibodies compared with 31% of the matched control children in the same age-group (odds ratio 3.7, 95% CI 1.2-11.4). The frequency of adenovirus infections did not differ between the patient and control groups. Our data imply that enterovirus infections are associated with the development of beta-cell autoimmunity and provide evidence for the role of enteroviruses in the initiation of beta-cell destruction.

Alleles↗

PubMed2000

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.

Adolescent↗

PubMed1999

Simultaneous detection of IFN-gamma and IL-4 mRNAs using RT-PCR and time-resolved fluorometry.

Time-resolved fluorometry was applied in the detection of RT-PCR amplified mRNAs for the Th1 and Th2 cell-derived cytokines interferon gamma (IFN-gamma) and interleukin (IL-)4, respectively. RNA stimulated cells was reverse transcribed and the cDNAs for the cytokine mRNAs and the constantly expressed beta-actin (beta-ACT) mRNA were simultaneously amplified in one multiplex PCR reaction. The PCR conditions were optimized to minimize mutual inhibition of individual amplifications. One of the PCR primers in each primer pair was biotinylated, and the PCR products were captured onto streptavidin-coated microtitre plates. The three PCR products were detected with three different lanthanide labelled target-specific probes in solution hybridization. IFN-gamma, IL-4 and beta-ACT were detected with europium (Eu), terbium (Tb) and samarium (Sm) labelled probes, respectively, using time-resolved fluorometry. Small cell numbers used in microtitre plate cultures were sufficient to detect cytokine messages after mitogen stimulation. This sequence-based method provides a sensitive, specific, fast and nonisotopic alternative to conventional blotting and hybridisation with radioactive probes. In addition, the multiplex fluorogenic dye detection facilitates relative quantification of target mRNAs.

Actins↗

PubMed1999

T cell responses to enterovirus antigens and to beta-cell autoantigens in unaffected children positive for IDDM-associated autoantibodies.

Enterovirus infections have been implicated in the pathogenesis of IDDM in a number of studies. The aim of the present study was to evaluate whether the cellular immune response to enterovirus antigens is abnormal in children who test positive for IDDM-associated autoantibodies. Lymphocyte proliferation responses were analysed to enterovirus antigens and to a panel of beta-cell autoantigen preparations in 31 non-diabetic ICA and/or GAD65 antibody-positive children and in 19 ICA/GAD65-negative control children. The responses to highly purified enteroviruses did not differ between autoantibody (AA)-positive and -negative subjects. However, proliferation responses to coxsackievirus-infected cell lysate, which also included non-structural proteins of the virus, were higher in AA-positive than in AA-negative subjects (P<0.05). This difference was most marked in children carrying the HLA-DQB1*02 allele (P=0.01). AA-positive subjects also had higher responses to one of the three GAD65 antigen preparations compared to AA-negative subjects (P<0.05). Proliferation responses to the adenovirus hexon protein did not differ between the groups. These results show that the increased responses to virus infected cell lysates are associated with early phases of beta-cell autoimmunity.

Adolescent↗

PubMed1999

Lack of induction by rhinoviruses of systemic type I interferon production or enhanced MxA protein expression during the common cold.

To study whether MxA protein expression is systemically upregulated during rhinovirus infection, blood specimens were collected from 40 patients with common cold and MxA expression in mononuclear cells analyzed by flow cytometry. None of the patients with a confirmed rhinovirus infection (n = 15) or with an infection of unknown etiology (n = 20) had elevated expression of the MxA protein (median fluorescence intensity, 549 and 582, respectively) when compared to healthy controls (n = 11, median 590). Patients with influenza infections had significantly elevated values (n = 5, median 750), and interferon could be detected only in serum samples from influenza patients. In conclusion, expression of MxA in blood lymphocytes and an apparently systemic type I interferon response is not induced during rhinovirus infection or during most other cases of common cold in young adult patients.

Adult↗

PubMed1999

Relation between T-cell responses to glutamate decarboxylase and coxsackievirus B4 in patients with insulin-dependent diabetes mellitus.

BACKGROUND: the role of enteroviruses has been implicated in the etiology of insulin-dependent diabetes mellitus (IDDM). A possible connection between glutamate decarboxylase (GAD) autoimmunity and enterovirus infections in IDDM has been suggested to be based on a homology region between GAD and the non-structural protein 2C of coxsackievirus B4 (CVB4). OBJECTIVES: the aims of the study were to measure the occurrence of cellular immunity to GAD and CVB4 in Finnish patients with newly diagnosed IDDM, and to study the relation between these two responses. T-cell responses to GAD and CVB4 were analyzed in relation to HLA DQB1 risk alleles for IDDM and antibodies to GAD and CVB4. STUDY DESIGN: T-cell and antibody responses to GAD65 and purified CVB4 were measured in patients with newly diagnosed IDDM and in healthy children. The purified CVB4 did not contain the non-structural protein 2C thus lacking the reported homology region with GAD. RESULTS: high proliferative responses of PBMC to both GAD and CVB4 were more frequent in IDDM patients than in the control children (40 vs. 16%, 27 vs. 10%; P = 0.03 and 0.04, respectively; Fisher's exact test), when the cut-off for positivity was three multiples of the median SI in the healthy children. Median SI to GAD was higher in the patients with IDDM than in the control subjects (3.10 vs. 1.55; P = 0.03, Mann-Whitney U-test). T-cell responses to GAD and CVB4 showed a positive correlation in the patients (r = 0.62, P = 0.001), but not in the control children (r = 0.23; P = 0.38). CONCLUSIONS: enhanced T-cell responsiveness to CVB4 in patients with newly diagnosed IDDM support the involvement of enteroviral infections in the development of IDDM. The observed correlation between T-cell reactivity to GAD and CVB4, lacking the crossreactive protein 2C, in patients with IDDM suggests that CBV4 reactivity is associated with GAD autoimmunity in IDDM but does not reflect immunization to GAD.

Adolescent↗

PubMed1999

Jejuna of patients with insulin-dependent diabetes mellitus (IDDM) show signs of immune activation.

The roles of enteric viruses and food antigens as possible triggers in human insulin-dependent diabetes mellitus and the evidence that mucosal-associated homing receptors are important in both human and experimental diabetes prompted us to undertake an immunohistochemical study of intestinal specimens from patients with IDDM. We studied jejunal morphology and immunohistochemistry in 26 patients with IDDM, 13 of whom had the HLA-DQB1*0201 gene and therefore a higher risk of coeliac disease. The findings were compared with those in specimens from age-matched controls. Villous structure and the density of the intraepithelial lymphocytes were normal in every biopsy specimen. The extent of positivity with anti-DR and -DP antibodies in the villous epithelium was significantly greater in the specimens from patients than in those from controls (P = 0.0002 in both comparisons). The crypts were also more positive: for DR P = 0.0001, and for DP P = 0.002. The densities of T cells, CD4+, CD8+, and T cell receptor alpha/beta+ and gamma/delta+ cells in the epithelium and lamina propria were similar in patients and controls, but the patients had significantly more alpha 4/beta 7 integrin+ cells in the lamina propria (P = 0.006). No difference was seen between HLA-DQB1*0201-positive and -negative patients. These findings reflect a stage of inflammation in the structurally normal intestines of patients with IDDM and suggest secretion of inflammatory Th1-type cytokines in the intestine.

Diabetes Mellitus, Type 1↗