High-risk Human Leukocyte Antigen Research Articles

Timing of complementary food introduction and age at diagnosis of type 1 diabetes: the SEARCH nutrition ancillary study (SNAS).

The association between timing of complementary food introduction and age at diagnosis of type 1 diabetes was investigated among 1077 children in the SEARCH for Diabetes in Youth study. Age at diagnosis was 5-month earlier for children introduced to sugar-sweetened beverages (SSB) in the first 12 months of life compared to those who were not (9.0 ± 0.2 vs. 9.5 ± 0.1; p=0.02), independent of HLA-risk status. Analyses stratified by HLA-risk status found that children with a high risk HLA genotype had an earlier age at diagnosis if they were introduced to fruit juice in the first year of life (mean age of diagnosis=9.3 ± 0.1, 9.1 ± 0.1 and 9.6 ± 0.2 for introduction at ≤ 6 months, between 7 and 11 months, and ≤12 months, respectively; p=0.04). Introduction of SSB in the first year of life may accelerate onset of type 1 diabetes independent of HLA-risk status.

Insulin Administration May Trigger Type 1 Diabetes in Japanese Type 2 Diabetes Patients With Type 1 Diabetes High-Risk HLA Class II and the Insulin Gene VNTR Genotype

Insulin administration causes various types of immune responses to insulin. We previously reported three cases of type 1 diabetes mellitus (T1DM) triggered by insulin administration in Japanese type 2 diabetes mellitus patients. The objective of this study was to collect information and characterize insulin-triggered T1DM immunologically and genetically. Data for six patients (four men and two women) with insulin-triggered T1DM aged 59.5 ± 12.8 years were collected. Serum or urinary C-peptides, islet-related autoantibodies, insulin antibody, human leukocyte antigen, or the insulin gene variable number of tandem repeat genotype were analyzed. Th1- or Th2-associated responses were evaluated using an Enzyme-Linked ImmunoSpot assay. None of the subjects had received insulin therapy or had an autoantibody to the 65-kDa isoform of glutamic acid decarboxylase before insulin administration. After insulin administration blood glucose control deteriorated acutely without any apparent cause, whereas C-peptide levels rapidly decreased to insulin-deficient levels. The mean duration of insulin administration to the development of T1DM was 7.7 ± 6.1 months. Islet-related autoantibodies became positive, whereas insulin allergy or a high titer of insulin antibody was observed in several cases. All had T1DM high-risk human leukocyte antigen class II (IDDM1) and the insulin gene variable number of tandem repeats genotype (IDDM2). GAD-reactive and insulin peptide-reactive Th1 cells, but not Th2 cells, were identified in two of four cases. The findings suggest that insulin administration may have triggered TIDM in patients with type 2 diabetes mellitus. IDDM1 and IDDM 2 as well as autoreactive T cells may contribute to the development of T1DM. Developing insulin-triggered T1DM if a patient's blood glucose control acutely deteriorates after insulin administration should be carefully considered.

Changes in the Clinical Impact of High-Risk Human Leukocyte Antigen Allele Mismatch Combinations on the Outcome of Unrelated Bone Marrow Transplantation

Several high-risk HLA allele mismatch combinations (HR-MMs) for severe acute graft-versus-host disease (GVHD) have been identified by analyzing transplantation outcomes in Japanese unrelated hematopoietic stem cell transplant recipients. In this study, we analyzed the effects of HR-MMs in 3 transplantation time periods. We confirmed that the incidence of grade III to IV acute GVHD in the HR-MM group was significantly higher than that in the low-risk (LR) MM group (hazard ratio [HR], 2.74; P < .0001) in the early time period (1993 to 2001). However, the difference in the incidence of grade III to IV acute GVHD between the HR-MM and LR-MM groups was not statistically significant (HR, 1.06; P = .85 and HR, .40; P = .21, respectively) in the mid (2002 to 2007) and late (2008 to 2011) time periods. Similarly, survival in the HR-MM group was significantly inferior to that in the LR-MM group (HR, 1.46; P = .019) in the early time period, whereas the difference in survival between the 2 groups was not statistically significant in the mid and late time periods (HR, 1.06; P = .75 and HR, .82; P = .58, respectively). In conclusion, the adverse impact of HR-MM has become less significant over time. Unrelated transplantation with a single HR-MM could be a viable option in the absence of a matched unrelated donor or an unrelated donor with a single LR-MM.

Early postnatal growth in children with HLA‐conferred susceptibility to type 1 diabetes

An association between increased length/height and weight gain and risk of type 1 diabetes (T1D) has been reported in children. We set out to investigate the potential contribution of T1D human leukocyte antigen (HLA) risk genotypes to this association in two countries with a contrasting disease incidence. In Estonia and Finland, length and weight were monitored up to the age of 24 months in 688 subjects. According to their HLA genotypes, the children were divided into four groups, those with very high, high or moderate risk for T1D, as well as a neutral/control group. Relative length and weight (SDS) were assessed and compared at 3, 6, 12, 18 and 24 months using World Health Organization (WHO) growth curves. The mean relative length at the age of 24 months was lower in the group with the very high risk HLA genotype compared to the controls (p < 0.05). The mean relative weight differed between those two groups at the age of 12, 18 and 24 months (p < 0.05). When Estonian and Finnish cohorts were analyzed separately, the relative length showed similar but non-significant trends in both countries, while in Estonia the changes in weight at some time points still remained significant (p < 0.05). Children with the highest HLA-conferred risk for T1D gained less weight and length during the first 24 months of life, and this feature was more pronounced in the Estonian children.

Viruses and type 1 diabetes: a new look at an old story

Epidemiological data suggesting an infectious origin of diabetes pre-date the discovery of insulin; indeed it was the variation in mortality rates from diabetes that led Gunderson to hypothesise that a virus with 'selective affinity for the pancreas' may cause 'acute diabetes' in youth (1). He noted an increase in deaths from diabetes in young people aged 10-20 yr in Norway from 1900 to 1921 following epidemics of parotitis, with a lag time of 3-4 yr between infection and death. In Norway, Denmark,France, and America, the increase in deaths from diabetes exceeded the expected number based on population growth; lending further weight to the proposal that diabetes was caused by infection. Since that time,a large body of epidemiological, clinical and experimental research, in humans, cellular and animal models, has provided further insights into the contribution of infections in the development of type 1 diabetes.Epidemiological evidence for a viral aetiology of diabetes A substantial body of epidemiological data point to a significant contribution of the environment in the development of type 1 diabetes,although much of the evidence is not specific to viruses per se. These data include rising rates of type 1 diabetes in both developed and developing countries in recent decades (2, 3) and a reduced contribution of high risk human leucocyte antigen (HLA) genotypes (4, 5), indicating that non-genetic factors are important. Similarly, the pairwise concordance between monozygotic twins for type 1 diabetes of less than 40%, and the observation that the incidence of diabetes in migrant children reflects that of their adopted country (6, 7), provide circumstantial evidence that environmental agents contribute to the disease. Space-time clustering in the presentation of type 1 diabetes (8-10) and clustering of births in children who subsequently develop diabetes (11) support a direct role for infections in the initiation and acceleration of the disease process.

Autoantibodies and High-Risk HLA Susceptibility Markers in First-Degree Relatives of Brazilian Patients with Type 1 Diabetes Mellitus: A Progression to Disease Based Study

The objective of this study was to determine the frequencies of autoantibodies to heterogeneous islet-cell cytoplasmic antigens (ICA), glutamic acid decarboxylase(65) (GAD(65)A), insulinoma-associated antigen-2 (IA-2A) and insulin (IAA)-and human leukocyte antigen (HLA) class II markers (HLA-DR and -DQ) in first degree relatives of heterogeneous Brazilian patients with type I diabetes (T1DM). A major focus of this study was to determine the influence of age, gender, proband characteristics and ancestry on the prevalence of autoantibodies and HLA-DR and -DQ alleles on disease progression and genetic predisposition to T1DM among the first-degree relatives. IAA, ICA, GAD(65)A, IA-2A and HLA- class II alleles were determined in 546 first-degree-relatives, 244 siblings, 55 offspring and 233 parents of 178 Brazilian patients with T1DM. Overall, 8.9% of the relatives were positive for one or more autoantibodies. IAA was the only antibody detected in parents. GAD(65) was the most prevalent antibody in offspring and siblings as compared to parents and it was the sole antibody detected in offspring. Five siblings were positive for the IA-2 antibody. A significant number (62.1%) of siblings had 1 or 2 high risk HLA haplotypes. During a 4-year follow-up study, 5 siblings (expressing HLA-DR3 or -DR4 alleles) and 1 offspring positive for GAD(65)A progressed to diabetes. The data indicated that the GAD(65) and IA-2 antibodies were the strongest predictors of T1DM in our study population. The high risk HLA haplotypes alone were not predictive of progression to overt diabetes.

Discordant association of islet autoantibodies with high‐risk HLA genes in Chinese type 1 diabetes

To reveal the aetiology of diabetes, the relationships between the islet autoantibodies, human leukocyte antigen (HLA)-A and DRB1 genotypes in the Chinese patients with type l diabetes (T1D) were investigated in our study. In the cross-sectional and case-control study, peripheral blood samples were collected from 600 T1D patients and 102 healthy controls. The genetic polymorphisms of HLA-A and DRB1 are examined with polymerase chain reaction-sequence oligonucleotide probe method. The zinc transporter 8 antibody (ZnT8A), glutamic acid decarboxylase antibody (GADA) and protein-tyrosine-phosphatase-2 autoantibody (IA2A) were detected by radioligand assay. The A*2402, DRB1*0301, DRB1*0405 and DRB1*0901 alleles, and A*1101-DRB1*0901, A*2402-DRB1*0405 and A*2402-DRB1*0901 haplotypes were associated with T1D (all p<0.05). The positive rates of ZnT8A in patients carried DRB1*0901, IA2A in patients carried DRB1*0405 and A*1101-DRB1*0901 and GADA in patients carried DRB1*0901 and A*2402-DRB1*0901 were significantly higher than those not carried (p<0.05). HLA-DRB1*0901 was the independent risk factor of positive antibody in T1D patients. In addition, higher body mass index is also related with the loss of islet function besides high-risk HLA gene and islet autoantibody (p<0.05). The discordant association of autoantibodies with high-risk HLA gene may indicate the different immunology mechanisms of those autoantibodies. And metabolic burden resulting from overweight may accelerate apoptosis of beta cells.

Country-specific birth weight and length in type 1 diabetes high-risk HLA genotypes in combination with prenatal characteristics.

Objective:To examine the relationship between high-risk human leukocyte antigen (HLA) genotypes for type 1 diabetes and birth size in combination with prenatal characteristics in different countries.Study Design:Four high-risk HLA genotypes were enrolled in the Environmental determinants of Diabetes in the Young study newborn babies from the general population in Finland, Germany, Sweden and the United States. Stepwise regression analyses were used to adjust for country, parental physical characteristics and environmental factors during pregnancy.Result:Regression analyses did not reveal differences in birth size between the four type 1 diabetes high-risk HLA genotypes. Compared with DQ 4/8 in each country, (1) DQ 2/2 children were heavier in the United States (P=0.028) mostly explained however, by parental weight; (2) DQ 2/8 (P=0.023) and DQ 8/8 (P=0.046) children were longer in Sweden independent of parents height and as well as (3) in the United States for DQ 2/8 (P=0.023), but again dependent on parental height.Conclusion:Children born with type 1 diabetes high-risk HLA genotypes have comparable birth size. Longitudinal follow-up of these children should reveal whether birth size differences between countries contribute to the risk for islet autoimmunity and type 1 diabetes.

The association between the PTPN22 1858C&gt;T variant and type 1 diabetes depends on HLA risk and GAD65 autoantibodies

The single nucleotide polymorphism 1858C>T in the PTPN22 gene is associated with type 1 diabetes (T1D) in several populations. Earlier reports have suggested that the association may be modified by human leukocyte antigen (HLA), as well as by islet autoantibodies. In a large case-control study of Swedish incident T1D patients and controls, 0-34 years of age, we tested whether the odds ratio (OR) measure of association was dependent on HLA or autoantibodies against the islet autoantigens glutamic acid decarboxylase 65 kDa autoantibodies (GADA), insulin, islet antigen-2, or islet cell. The association between the carrier status of 1858C>T allele in PTPN22 (PTPN22(CT+TT)) and T1D was modified by HLA. In addition, in GADA-positive T1D, the OR was 2.83 (2.00, 3.99), whereas in GADA-negative T1D, the OR was 1.41 (0.98, 2.04) (P for comparison=0.007). The OR of association between PTPN22(CT+TT) and GADA-positive T1D declined with increasing HLA-risk category from 6.12 to 1.54 (P=0.003); no such change was detected in GADA-negative T1D (P=0.722) (P for comparison=0.001). However, the absolute difference in risk between PTPN22(CC) and PTPN22(CT+TT) subjects with high-risk HLA was five times higher than that for subjects with low-risk HLA. We hypothesize that the altered T-cell function because of the PTPN22(1858C>T) polymorphism is exclusively associated with GADA-positive T1D at diagnosis.

Genetic variation within the HLA class III influences T1D susceptibility conferred by high-risk HLA haplotypes

HLA class II DRB1 and DQB1 represent the major type 1 diabetes (T1D) genetic susceptibility loci; however, other genes in the HLA region are also involved in T1D risk. We analyzed 1411 pedigrees (2865 affected individuals) from the type 1 diabetes genetics consortium (T1DGC) genotyped for HLA classical loci and for 12 SNPs in the class III region previously shown to be associated with T1D in a subset of 886 pedigrees. Using the transmission disequilibrium test, we compared the proportion of SNP alleles transmitted from within the high risk DR3 and DR4 haplotypes to affected offspring. Markers rs4151659 (mapping to CFB) and rs7762619 (mapping 5′ of LTA) were the most strongly associated with T1D on DR3 (p=1.2 × 10−9 and p=2 × 10−12 respectively) and DR4 (p=4 × 10−15 and p= 8 × 10−8 respectively) haplotypes. They remained significantly associated after stratifying individuals in analyses for B*1801, A*0101-B*0801, DPB1*0301, DPB1*0202, DPB1*0401 or DPB1*0402. Rs7762619 and rs4151659 are in strong linkage disequilibrium (LD) (r2=0.82) with each other, but a joint analysis showed that the association for each SNP was not solely due to LD. Our data support a role for more than one locus in the class III region contributing to risk of T1D.

Reproducible association with type 1 diabetes in the extended class I region of the major histocompatibility complex

The high-risk human leukocyte antigen (HLA)-DRB1, DQA1 and DQB1 alleles cannot explain the entire type 1 diabetes (T1D) association observed within the extended major histocompatibility complex. We have earlier identified an association with D6S2223, located 2.3 Mb telomeric of HLA-A, on the DRB1(*)03-DQA1(*)0501-DQB1(*)0201 haplotype, and this study aimed to fine-map the associated region also on the DRB1(*)0401-DQA1(*)03-DQB1(*)0302 haplotype, characterized by less extensive linkage disequilibrium. To exclude associations secondary to DRB1-DQA1-DQB1 haplotypes, 205 families with at least one parent homozygous for these loci, were genotyped for 137 polymorphisms. We found novel associations on the DRB1(*)0401-DQA1(*)03-DQB1(*)0302 haplotypic background with eight single nucleotide polymorphisms (SNPs) located within or near the PRSS16 gene. In addition, association at the butyrophilin (BTN)-gene cluster, particularly the BTN3A2 gene, was observed by multilocus analyses. We replicated the associations with SNPs in the PRSS16 region and, albeit weaker, to the BTN3A2 region, in an independent material of 725 families obtained from the Type 1 Diabetes Genetics Consortium. It is important to note that these associations were independent of the HLA-DRB1-DQA1-DQB1 genes, as well as of associations observed at HLA-A, -B and -C. Taken together, our results identify PRSS16 and BTN3A2, two genes thought to play important roles in regulating the immune response, as potentially novel susceptibility genes for T1D.

Characterization of the humoral immune response to islet antigen 2 in children with newly diagnosed type 1 diabetes.

To characterize the humoral immune response to islet antigen 2 (IA-2) in patients with newly diagnosed type 1 diabetes (T1D), we compared the profile of epitope- and isotype-specific IA-2 antibodies (IA-2A) between children with a humoral immune response restricted to IA-2 and children with a broad response including insulin autoantibodies (IAA) and antibodies to glutamic acid decarboxylase (GADA) in addition to IA-2A. The study subjects (n=100) were derived from a consecutive series of 1108 patients from the Finnish Pediatric Diabetes Register (investigators listed in the Appendix). Islet cell antibodies, IAA, GADA, total IA-2A levels, IA-2/IA-2beta epitopes, and isotypes were measured, and human leukocyte antigen (HLA) genotypes were analyzed. There were no significant differences between the two groups in the frequency or levels of epitope-specific IA-2A. Those with an IA-2-restrictive response tested positive more frequently for IgA-IA-2A (P=0.001), had higher titers of IgE-IA-2A (P=0.025), tested positive for more IA-2A isotypes than the broad responders (P=0.04), and carried the high-risk HLA-(DR4)-DQB1*0302 haplotype more frequently than those with a broad antibody response (P=0.019). These data show that children with newly diagnosed T1D, who test positive only for IA-2A out of the three molecular antibodies predictive of T1D, have a broader IA-2-specific isotype response and stronger association with the high-risk HLA haplotype than those testing positive for all three molecular antibodies. This may be indicative of a different pathogenetic mechanism in those with their humoral immune response restricted to IA-2 at the time of diagnosis.

Type 1 diabetes risk for human leukocyte antigen (HLA)-DR3 haplotypes depends on genotypic context: Association of DPB1 and HLA class I loci among DR3- and DR4-matched Italian patients and controls

Patients with high-risk human leukocyte antigen (HLA)-DR-DQ genotypes for type 1 diabetes (T1D) were compared with HLA-matched controls to evaluate T1D risk for other HLA loci, including HLA-A, -B, -Cw, and DPB1. Patients (n = 133) with high-risk genotypes (DR3/DR3, DR3/DR4, DR4/DR4) were selected from the Lazio (Rome) region of Italy. Screening of more than 9000 patients from the Lazio region and northern Italy yielded 162 controls with high-T1D-risk haplotypes. Although the overall distributions did not differ significantly, allele frequency differences were discovered between the controls from Lazio and controls from northern Italy for some alleles previously determined to affect T1D risk, such as A*3002, DPB1*0301, and DPB1*0402. Therefore, Lazio patient data were compared both with the Lazio subset of controls (n = 53) and with the entire group of controls for association analyses. Significant allele frequency differences between patients and DR-DQ-matched controls existed for specific alleles at all loci. Data for the DR3/DR3 subset of patients and controls demonstrated an increase of Cw*0702 in patients. Compared with controls, reduced patient frequencies were seen for several alleles, including A*0101, B*0801, and Cw*0701, all on the highly conserved, extended DR3 haplotype known as 8.1 in DR3/DR3, but not DR3/DR4, subgroup. DPB1*0101, often reported on 8.1 haplotypes, was also less frequent in DR3/DR3 patients than controls. Analysis of family-based data from the HBDI repository was consistent with the observed results from the Italian patients, indicating the presence of a T1D-protective locus at or near A*0101 and a second T1D-protective locus at or near DPB1*0101. These data indicate that T1D risk conferred by the 8.1 haplotype is genotype dependent.

The Environmental Determinants of Diabetes in the Young (TEDDY) study: study design

The primary objective of this multicenter, multinational, epidemiological study is the identification of infectious agents, dietary factors, or other environmental exposures that are associated with increased risk of autoimmunity and type 1 diabetes mellitus (T1DM). Factors affecting specific phenotypic manifestations such as early age of onset or rate of progression or with protection from the development of T1DM will also be identified. The Environmental Determinants of Diabetes in the Young (TEDDY) is an observational cohort study in which newborns who are younger than 4 months and have high-risk human leukocyte antigen alleles in the general population or are first-degree relatives (FDRs) of patients affected with T1DM will be enrolled. Six clinical centers in the USA and Europe will screen 361,588 newborns, of which it is anticipated that 17,804 will be eligible for enrollment with just over 7,800 followed. Recruitment will occur over 5 yr, with children being followed to the age of 15 yr. Identification of such factors will lead to a better understanding of disease pathogenesis and result in new strategies to prevent, delay, or reverse T1DM.

Atherogenic vascular and lipid phenotypes in young patients with Type 1 diabetes are associated with diabetes high-risk HLA genotype

Expression of human leukocyte antigen (HLA) class II molecules on islet endothelial cells is a central vascular event in the pathogenesis of Type 1 diabetes. Previous studies demonstrated the ability of other vascular endothelial cells to express HLA and thereby to process islet autoantigens on their surface. We investigated whether the HLA-DQ2/8 genotype, which confers the highest risk for Type 1 diabetes, is associated with early atherosclerosis in youths with this disease. Brachial artery endothelium-dependent, flow-mediated dilation (BA-FMD) and carotid artery intima-media thickness (CA-IMT), as well as markers of systemic inflammation [C-reactive protein (CRP), fibrinogen, and orosomucoid], HbA(1C), LDL, HDL, and total cholesterol, were assessed in 86 children and adolescents with Type 1 diabetes (mean age and diabetes duration, 15 and 7 yr, respectively) between 2004 and 2006. HLA genotypes were determined in dried blood spots by an oligoblot hybridization method. As a result, HLA-DQ2/8 was detected in 34 patients (DQ2/8). When this group was compared with the remaining patients (non-DQ2/8, n = 52), there were no differences in age, diabetes duration, HbA(1C), body mass index, inflammatory markers, and IMT (P > or = 0.4). In the DQ2/8 group, LDL-to-HDL ratio was elevated compared with that in the non-DQ2/8 group (1.8 vs. 1.3, respectively; P = 0.001), whereas FMD did not significantly differ between the groups (5.3% vs. 6.7%, respectively; P = 0.08). When patients were further categorized in relation to CRP (cut-off value, 1 mg/l), BA-FMD was significantly lower (3%, P < 0.01), whereas LDL-to-HDL ratio increased further (2.2, P < 0.001) in the subgroup of DQ2/8 and CRP > or = 1 patients compared with the remaining three subgroups. These associations remained significant after adjustment for age, diabetes duration, and HbA(1C) by analysis of covariance. The brachial artery responses to nitroglycerine were similar in all subgroups. In conclusion, the diabetes-predisposing HLA-DQ2/8 genotype in children and adolescents with Type 1 diabetes interferes with endothelial and lipid-related mechanisms of early atherosclerosis, possibly in part through inflammatory pathways.

Autoantibody epitopes to the smaller isoform of glutamate decarboxylase do not differ in Swedish and Japanese type 1 diabetes patients and may be associated with high-risk human leucocyte antigen class II alleles

Type 1 diabetes (T1D) is an autoimmune disease with a strong human leucocyte antigen (HLA) class II association. Depending on geographic locations, the disease-associated HLA class II alleles vary. We evaluated the beta cell-specific autoimmunity reflected in autoantibodies directed to the smaller isoform of glutamate decarboxylase (GAD65) in Japanese and Swedish T1D patients. GAD65Ab epitope specificities were assessed using GAD65-specific recombinant Fab. GAD65Ab epitope specificities did not differ between Swedish and Japanese patients. Only recognition of the MICA-4-defined middle epitope was significantly stronger in the Japanese T1D patient group compared to the Swedish T1D patients (P = 0.001). Binding to the b96.11-defined middle epitope was substantial in both groups and showed significant associations with high-risk HLA class II haplotypes. In the Japanese T1D group the association was with haplotype DRB1*0802-DQB1*0302 (P = 0.0008), while in the Swedish T1D patients binding to the b96.11-defined epitope as associated with the presence of high-risk HLA genotypes DR3-DQB1*0201 and/or DR4-DQB1*0302 (P = 0.02). A significant association between reduction in binding in the presence of recombinant Fab (rFab) DPD and high-risk allele DQB1*0201 was found (P = 0.008) in the Swedish T1D patients only. We hypothesize that epitope-specific autoantibodies effect the peptide presentation on HLA class II molecules by modulating antigen uptake and processing. Molecular modelling of the high-risk HLA class II molecules will be necessary to test whether these different molecules present similar peptide-binding specificities.

Contrasting cellular and humoral autoimmunity associated with latent autoimmune diabetes in adults

Diabetes is clinically classified into two types: type 1 (T1D) and type 2 diabetes (T2D). Nevertheless, intermediate forms of diabetes are frequent and difficult to recognize and manage appropriately. In this study, we investigated whether patients with intermediate form of diabetes, here called unclassified diabetes (UD), have beta-cell autoimmune markers. beta-cell autoimmune markers (beta-cell autoantibodies (aAb), peripheral blood mononuclear cells (PBMC) responsive to five islet proteins, cytokine secretion, and human leukocyte antigen (HLA)-DQB1 genotypes) were analyzed in 50 UD patients, 23 age- and HLA-matched normal control subjects, and 23 classic T2D patients. We observed that 16 out of 50 (32%) UD patients demonstrated responsive PBMCs, as opposed to 1 out of 23 (5%) age- and HLA-matched normal control subjects, and 0 out of 23 classic T2D patients. Overall, 29 (58%) UD patients had at least one marker of beta-cell autoimmunity (beta-cell aAb and/or PBMC autoreactivity), in association with high-risk HLA genotypes DQB1*0201 and/or DQB1*0302. Moreover, the 13 (26%) UD patients who had beta-cell aAb were not the same as those with PBMC autoreactivity, except for one patient. Patients with PBMC autoreactivity were older at the onset of the disease and had a better residual beta-cell function than those with beta-cell aAb. Our data confirm that T-cell autoimmunity can be detected in latent autoimmune diabetes in adults patients. We show an inverse correlation between humoral and cellular beta-cell autoimmunities. Possible protective cellular responses in the patients with beta-cell PBMC autoreactivity could have potential therapeutic implications.

Immune Regulatory T Cells in Siblings of Children Suffering from Type 1 Diabetes Mellitus

Patients with type 1 diabetes are suffering from defects in immune regulatory cells. Their siblings may be at increased risk of type 1 diabetes especially if they are carriers of certain human leucocyte antigen (HLA) alleles. In a prospective non-randomized study, we intended to evaluate 31 healthy siblings of paediatric patients with type 1 diabetes and explore immune regulatory populations of CD4+CD25+ T cells and natural killer (NK) T cells. Tested siblings of type 1 diabetes patients were stratified according to the HLA-associated risk of possible diabetes development. Immune regulatory function of CD4+CD25+ T cells was tested in vitro. Significant differences in CD4+CD25+ but not in NK T cells have been identified. Siblings of type 1 diabetes patients carrying high risk HLA alleles (DQA1*05, DQB1*0201, DQB1*0302) had significantly lower number of immune regulatory CD4+CD25+ T cells than the age-matched healthy controls or siblings carrying low-risk HLA alleles (DQB1*0301, DQB1*0603, DQB1*0602). Regulatory function of CD4+CD25+ T cells demonstrated a dose-escalation effect. In siblings of type 1 diabetes patients, the defect in immune regulatory CD4+CD25+ T cells exists in association with genetic HLA-linked risk for type 1 diabetes.

Interleukin-12p40 gene (IL-12B) polymorphism and Type 1 diabetes mellitus in Japanese: Possible role in subjects without having high-risk HLA haplotypes

The present study was undertaken to clarify a role of interleukin-12p40 gene (IL-12B) polymorphism, located on chromosome 5q33-34 (IDDM 18), in Japanese subjects with Type 1 diabetes mellitus (T1DM) and autoimmune thyroid diseases (AITD). In 179 subjects with T1DM, 166 with AITD (128 with Graves’ disease and 38 with Hashimoto's thyroiditis) and 115 healthy control subjects, the IL-12B 3′UTR A-C polymorphism was determined by PCR-RFLP method. In T1DM subjects, the genotype was also analyzed in relation to human leukocyte antigen (HLA)-DRB1-DQB1 haplotype status. There was a weak difference in the distribution of the genotype frequency between T1DM and control subjects, and the C allele frequency was higher in T1DM subjects ( P < 0.05). In 68 T1DM subjects without having high-risk HLA haplotypes to T1DM in this population, the genotype distribution and C allele frequency was significantly different from control subjects without high-risk HLA haplotypes ( P < 0.01), and from T1DM subjects with high-risk HLA haplotypes ( n = 111) ( P < 0.05). There was no difference in the genotype and allele frequencies between AITD and control subjects. In conclusion, the IL-12B 3′UTR A-C polymorphism did not seem to play a major role on genetic susceptibility to T1DM and AITD in Japanese, although the polymorphism conferred susceptibility in T1DM subjects without having high-risk HLA haplotypes. The IL-12B 3′UTR A-C polymorphism would be considered as a supplementary risk factor to T1DM in conjunction with HLA haplotypes.

Clinicopathological and virological analyses of familial human T-lymphotropic virus type I–associated polyneuropathy

Human T-lymphotropic virus type I (HTLV-I) is known to be the causative agent of the chronic myelopathy, HTLV-I--associated myelopathy (HAM), and on rare occasions infection is also associated with the development of polyneuropathy. Here the authors present an HTLV-I--positive family of whom four members developed a chronic demyelinating polyneuropathy without HAM. Four female patients in a family from Hokkaido in Japan developed distal dominant paresthesia and muscle weakness in the second and third decades of their life. Neurological findings at ages ranging from 50 to 65 years included mild painful sensorimotor disturbances with atrophy of the distal parts of the extremities but without pyramidal signs or hyperactive tendon reflexes. Magnetic resonance imaging (MRI) findings of brain and spinal cord were unremarkable. Serum HTLV-I antibody levels were elevated at 1:8192 to 1:32,768, whereas those in cerebrospinal fluid were low at 1:4 to 1:8. Electrophysiological studies revealed polyphasic compound muscle action potentials with denervation potentials on nerve conduction studies and neurogenic patterns by electromyography, which were consistent with signs of chronic motor dominant demyelinating polyneuropathy. Sural nerve biopsy showed decreased myelinated fibers, occurrence of globule formation, myelin ovoid and remyelinated fibers, and an infiltration of CD68-positive macrophages with occasional CD4-positive T cells in the nerve fascicles. The polyneuropathy was responsive to steroid therapy. Analyses of serological human leukocyte antigen (HLA) types indicated that none of the patients possessed a high-risk HLA type known to be associated with adult T-cell leukemia (ATL), whereas they did have high responsive alleles to HTLV-I env similar to that observed in HAM. Nucleotide sequence analysis of the HTLV-I tax region demonstrated the B subgroup in all patients. This study suggests that HTLV-I infection can result in the development of a familial form of polyneuropathy that is associated with distinct HLA class I alleles, which might possibly involve a distinct virus subtype.