Taylor K. Armstrong

Additional Autoimmune Disease Found in 33% of Patients at Type 1 Diabetes Onset

OBJECTIVE We sought to define the prevalence of nonislet, organ-specific autoantibodies at diagnosis of type 1 diabetes and to determine the prevalence of comorbid autoimmune diseases. RESEARCH DESIGN AND METHODS Children (n = 491) diagnosed with type 1 diabetes at the Barbara Davis Center for Childhood Diabetes were screened for autoimmune thyroid disease (thyroid peroxidase autoantibodies [TPOAb]), celiac disease (tissue transglutaminase autoantibodies [TTGAb]), and Addison disease (21-hydroxylase autoantibodies [21OHAb]). RESULTS Of the 491 children, 161 had at least one nonislet autoantibody, and of these, 122 (24.8%) were positive for TPOAb, and 15 of the 122 (12.3%) had autoimmune thyroid disease. There were 57 (11.6%) who were positive for TTGAb, of whom 14 (24.6%) had celiac disease. Five (1.0%) were positive for 21OHAb, of whom one had Addison disease. CONCLUSIONS Many autoantibody-positive subjects present with additional autoimmune disorders. Detection of these autoantibodies at type 1 diabetes onset may prevent complications associated with delayed diagnosis of these disorders.

Stepwise or Linear Decrease in Penetrance of Type 1 Diabetes With Lower-Risk HLA Genotypes Over the Past 40 Years

OBJECTIVE The objective of this study was to test if the proportion of new-onset diabetic subjects with the HLA-DR3/4-DQB1*0302 genotype is decreasing over time. RESEARCH DESIGN AND METHODS We analyzed HLA class II genotype frequencies over time in two large populations with type 1 diabetes diagnosed at ≤18 years of age. There were 4,075 subjects from the Type 1 Diabetes Genetics Consortium (T1DGC) and 1,675 subjects from the Barbara Davis Center (BDC). RESULTS Both T1DGC and BDC cohorts showed a decrease of the highest-risk HLA-DR3/4-DQB1*0302 genotype over time. This decrease was greatest over time in T1DGC subjects with age of onset ≤5 years (P = 0.004) and onset between ages 6 and 10 years (P = 0.002). The overall percent of HLA-DR3/4-DQB1*0302 was greater in the T1DGC population compared with the BDC population. There was an increased percent over time of other HLA genotypes without HLA-DR3 or -DR4 in T1DGC new onsets (P = 0.003), and the trend was similar in BDC subjects (P = 0.08). Analyzing time trend, there appears to be a large stepwise decrease in percent DR3/4 in the 1980s in T1DGC subjects with onset age <5 years (P = 0.0001). CONCLUSIONS The change in frequency of multiple different genotypes and a possible stepwise decrease in percent DR3/4 suggest a change in genetic risk factors and environmental determinants of type 1 diabetes. Larger studies are needed to confirm the changing pattern of genetic risk because a stepwise change may have direct bearing on defining critical environmental determinants of type 1 diabetes.

Persistently autoantibody negative (PAN) type 1 diabetes mellitus in children.

Hameed S, Ellard S, Woodhead HJ, Neville KA, Walker JL, Craig ME, Armstrong T, Yu L, Eisenbarth GS, Hattersley AT, Verge CF. Persistently autoantibody negative (PAN) type 1 diabetes mellitus in children.

Homozygosity of the Polymorphism MICA5.1 Identifies Extreme Risk of Progression to Overt Adrenal Insufficiency among 21-Hydroxylase Antibody-Positive Patients with Type 1 Diabetes

CONTEXT Autoimmunity associated with Addisons disease (AD) can be detected by measuring 21-hydroxylase (21OH) autoantibodies. Subjects with type 1 diabetes (T1D) are at increased risk for AD. Genetic factors including HLA-DRB1*0404 and MICA have been associated with AD in populations with and without T1D. OBJECTIVE The objective of the study was to examine the effect of the MICA5.1 allele in subjects with 21OH autoantibodies on progression to AD. DESIGN Two components were used: 1) a cross-sectional study with subjects with AD identified and enrolled from September 1993 to November 2008 and 2) a cohort study prospectively following up patients with T1D who screened positive for 21OH autoantibodies. SETTING Subjects were identified from the Barbara Davis Center and through the National Adrenal Diseases Foundation. PATIENTS Sixty-three subjects with AD were referred through the National Adrenal Diseases Foundation (AD referrals). Sixty-three subjects with positive 21OH antibodies from the Barbara Davis Center were followed up for progression to AD, and 11 were diagnosed with AD (progressors). RESULTS Seventy-three percent of progressors (eight of 11) and 57% of AD referrals (36 of 63) were MICA5.1 homozygous (P = ns). Overall, 59% of patients with AD (44 of 74) were MICA5.1/5.1 compared with 17% of nonprogressors (nine of 52) (P < 0.0001) and 19% of normal DR3/4-DQB1*0302 controls (64 of 336) (P < 0.0001). CONCLUSIONS Identifying extreme risk should facilitate monitoring of progression from 21OH antibody positivity to overt AD. The HLA-DR3/0404 genotype defines high-risk subjects for adrenal autoimmunity. MICA5.1/5.1 may define those at highest risk for progression to overt AD, a feature unique to AD and distinct from T1D.

Haplotype Analysis Discriminates Genetic Risk for DR3-Associated Endocrine Autoimmunity and Helps Define Extreme Risk for Addison’s Disease

CONTEXT Multiple autoimmune disorders (e.g. Addisons disease, type 1 diabetes, celiac disease) are associated with HLA-DR3, but it is likely that alleles of additional genes in linkage disequilibrium with HLA-DRB1 contribute to disease. OBJECTIVE The objective of the study was to characterize major histocompatability complex (MHC) haplotypes conferring extreme risk for autoimmune Addisons disease (AD). DESIGN, SETTING, AND PARTICIPANTS Eighty-six 21-hydroxylase autoantibody-positive, nonautoimmune polyendocrine syndrome type 1, Caucasian individuals collected from 1992 to 2009 with clinical AD from 68 families (12 multiplex and 56 simplex) were genotyped for HLA-DRB1, HLA-DQB1, MICA, HLA-B, and HLA-A as well as high density MHC single-nucleotide polymorphism (SNP) analysis for 34. MAIN OUTCOME MEASURES AD and genotype were measured. RESULT Ninety-seven percent of the multiplex individuals had both HLA-DR3 and HLA-B8 vs. 60% of simplex AD patients (P = 9.72 × 10(-4)) and 13% of general population controls (P = 3.00 × 10(-19)). The genotype DR3/DR4 with B8 was present in 85% of AD multiplex patients, 24% of simplex patients, and 1.5% of control individuals (P = 4.92 × 10(-191)). The DR3-B8 haplotype of AD patients had HLA-A1 less often (47%) than controls (81%, P = 7.00 × 10(-5)) and type 1 diabetes patients (73%, P = 1.93 × 10(-3)). Analysis of 1228 SNPs across the MHC for individuals with AD revealed a shorter conserved haplotype (3.8) with the loss of the extended conserved 3.8.1 haplotype approximately halfway between HLA-B and HLA-A. CONCLUSION Extreme risk for AD, especially in multiplex families, is associated with haplotypic DR3 variants, in particular a portion (3.8) but not all of the conserved 3.8.1 haplotype.

Dominant Suppression of Addison's Disease Associated with HLA-B15

CONTEXT Autoimmune Addisons disease (AD) is the major cause of primary adrenal failure in developed nations. Autoantibodies to 21-hydroxylase (21OH-AA) are associated with increased risk of progression to AD. Highest genetic risk is associated with the Major Histocompatibility region (MHC), specifically human leukocyte antigen (HLA)-DR3 haplotypes (containing HLA-B8) and HLA-DR4. OBJECTIVE The objective of the study was the further characterization of AD risk associated with MHC alleles. DESIGN, SETTING, AND PARTICIPANTS MHC genotypes were determined for HLA-DRB1, DQA1, DQB1, MICA, HLA-B, and HLA-A in 168 total individuals with 21OH-AA (85 with AD at referral and 83 with positive 21OH-AA but without AD at referral). MAIN OUTCOME MEASURE(S) Genotype was evaluated in 21OH-AA-positive individuals. Outcomes were compared with general population controls and type 1 diabetes patients. RESULTS In HLA-DR4+ individuals, HLA-B15 was found in only one of 55 (2%) with AD vs. 24 of 63 (40%) 21OH-AA-positive nonprogressors (P = 2 × 10(-7)) and 518 of 1558 (33%) HLA-DR4 patients with type 1 diabetes (P = 1 × 10(-8)). On prospective follow-up, none of the HLA-B15-positive, 21-hydroxylase-positive individuals progressed to AD vs. 25% non-HLA-B15 autoantibody-positive individuals by life table analysis (P = 0.03). Single nucleotide polymorphism analysis revealed the HLA-DR/DQ region associated with risk and HLA-B15 were separated by multiple intervening single-nucleotide polymorphism haplotypes. CONCLUSIONS HLA-B15 is not associated with protection from 21OH-AA formation but is associated with protection from progression to AD in 21OH-AA-positive individuals. To our knowledge, this is one of the most dramatic examples of genetic disease suppression in individuals who already have developed autoantibodies and of novel dominant suppression of an autoimmune disease by a class I HLA allele.

Viral Cyclins Mediate Separate Phases of Infection by Integrating Functions of Distinct Mammalian Cyclins

Gammaherpesvirus cyclins have expanded biochemical features relative to mammalian cyclins, and promote infection and pathogenesis including acute lung infection, viral persistence, and reactivation from latency. To define the essential features of the viral cyclin, we generated a panel of knock-in viruses expressing various viral or mammalian cyclins from the murine gammaherpesvirus 68 cyclin locus. Viral cyclins of both gammaherpesvirus 68 and Kaposis sarcoma-associated herpesvirus supported all cyclin-dependent stages of infection, indicating functional conservation. Although mammalian cyclins could not restore lung replication, they did promote viral persistence and reactivation. Strikingly, distinct and non-overlapping mammalian cyclins complemented persistence (cyclin A, E) or reactivation from latency (cyclin D3). Based on these data, unique biochemical features of viral cyclins (e.g. enhanced kinase activation) are not essential to mediate specific processes during infection. What is essential for, and unique to, the viral cyclins is the integration of the activities of several different mammalian cyclins, which allows viral cyclins to mediate multiple, discrete stages of infection. These studies also demonstrated that closely related stages of infection, that are cyclin-dependent, are in fact genetically distinct, and thus predict that cyclin requirements may be used to tailor potential therapies for virus-associated diseases.

Formulation Considerations for DNA-Based Therapeutics

The ability to deliver genes to cells and tissues in vivo offers the potential to develop potent vaccines and treat many hereditary diseases that are currently considered incurable, e.g., cancer, cystic fibrosis (CF), severe combined immunodeficiency (SCID), and acquired immune deficiency syndrome (AIDS) (1-6). Considering the tremendous promise of DNA-delivery technology, in addition to the extensive genetic information now available from the Human Genome Project, it is not surprising that gene therapy is being touted as the next revolution in medicine. Although a strict definition of “gene therapy” would be limited to therapeutic approaches that aim to use polynucleotides as a template for the in vivo production of proteins, the term is often used to refer to a wide variety of strategies that employ nucleotide-based molecules (e.g., vaccines, antisense, ribozymes, siRNA). To date, 70 clinical protocols have been approved for the delivery of naked DNA, comprising approx 11% of the total number of gene-therapy clinical protocols (http://www.wiley.co.uk/genetherapy/clinical). Slightly more studies (~12%) have employed nonviral, lipid-based vectors to facilitate DNA delivery. In comparison, the large majority of clinical gene therapy trials (>70%) utilizes viruses to deliver therapeutic genes because viruses are more efficient than contemporary synthetic gene-delivery systems. The higher efficiency of viruses should not be surprising if we recognize that these organisms have been evolving their gene-delivery machinery for billions of years. In contrast, the development of nonviral systems for therapeutic gene delivery can be traced back a mere 15 years (7). Although more efficient nonviral gene-delivery systems continue to be developed, synthetic systems have yet to replicate the efficiency of viruses. One significant drawback of viral delivery is the immunogenicity of viruses, which causes significant inflammation in vivo (8), and eliminates the potential for multiple dosing (anyone who has ever had a cold is familiar with the fever and inflammation associated with an immune response to viruses). In fact, the adverse reactions associated with viral delivery have been implicated as the cause of death in clinical trials (9,10). Also, a clinical trial involving liver infusion of an adenoassociated virus (AAV) for the treatment of hemophilia B was halted because of the presence of the viral vector in patient semen, and the concern that the genetic alteration could be passed to offspring (11). More recently, two patients treated with ex vivo genetherapy for the treatment of SCID have developed leukemia owing to insertional mutagenesis caused by the retroviral vector used in the study (12,13). Considering the potential safety risk involved in employing viruses as a therapeutic moiety, there is renewed interest in developing safe, efficient, nonviral gene-delivery systems.

Replication and further characterization of a Type 1 diabetes‐associated locus at the telomeric end of the major histocompatibility complex

Background:  We recently reported an association between Type 1 diabetes and the telomeric major histocompatibility complex (MHC) single nucleotide polymorphism (SNP) rs1233478. As further families have been analyzed in the Type 1 Diabetes Genetics Consortium (T1DGC), we tested replication of the association and, with more data, analyzed haplotypic associations.

HLA similarities indicate shared genetic risk in 21-hydroxylase autoantibody positive South African and United States Addison's disease

Genetic similarities between patients from the United States and South African (SA) Addisons Disease (AD) strengthen evidence for genetic association. SA-AD (n = 73), SA healthy controls (N = 78), and US-AD patients (N = 83) were genotyped for DQA1, DQB1, DRB1, and HLA-B alleles. Serum was tested for the quantity of 21OH-AA and IFNα-AA at the Barbara Davis Center. Although not as profound as in US-AD, in SA-AD 21OH-AA + subjects the predominantly associated risk haplotypes were DRB1*0301-DQB1*0201 (DR3), DRB1*04xx-DQB1*0302 (DR4), and the combined DR3/4 genotype. DQB1*0302 associated DRB1*04xx haplotypes conferred higher risk than those DRB1*04xx haplotypes associated with other DQB1 alleles. We found negative association in 21OH-AA + SA-AD for DQA1*0201-DQB1*0202 and DQA1*0101-DQB1*0501 vs SA controls, and positive association for DQA1*0401-DQB1*0402 vs US-AD. Apart from the class II DR3 haplotype, HLA-B8 did not have an independent effect; however together DR3 and HLA-B8 conferred the highest risk vs 21OH-AA negative SA-AD and SA-controls. HLA-B7 (often with DR4) conferred novel risk in 21OH-AA + SA-AD vs controls. This study represents the first comparison between South African and United States AD populations utilizing genotyping and serology performed at the same center. SA-AD and US-AD 21OH-AA + patients share common HLA risk haplotypes including DR4 (with HLA-B7) and DR3 (with HLA-B8), strengthening previously described HLA associations and implicating similar genetic etiology.