1076 Diabetes Care Volume 41, May 2018 Else M. Balke,1 Eric V. Balti,1,2 Accelerated Progression to Type 1 Bart Van der Auwera,1 Ilse Weets,1,2 Olivier Costa,1,2 Simke Demeester,1,2 Diabetes in the Presence of Pascale Abrams,1,3 Kristina Casteels,1,4 Marina Coeckelberghs,1,5 HLA-A*24 and -B*18 Is Restricted Sylvie Tenoutasse,1,6 Bart Keymeulen,1,7 – Daniel G. Pipeleers,1 Frans K. Gorus,1,2 and to Multiple Islet Autoantibody the Belgian Diabetes Registry Positive Individuals With Distinct HLA-DQ and Autoantibody Risk Profiles Diabetes Care 2018;41:1076–1083 | https://doi.org/10.2337/dc17-2462 OBJECTIVE We investigated the effect of HLA class I risk alleles on disease progression in various phases of subclinical islet autoimmunity in first-degree relatives of patients with type 1 diabetes. RESEARCH DESIGN AND METHODS A registry-based group of siblings/offspring (aged 0–39 years) was monitored from 1Diabetes Research Center, Vrije Universiteit single- to multiple-autoantibody positivity (n = 267) and from multiple-autoantibody Brussel, Brussels, Belgium 2 positivity to clinical onset (n = 252) according to HLA-DQ, -A*24, -B*18,and-B*39 Department of Clinical Chemistry, Universitair fi Ziekenhuis Brussel, Brussels, Belgium status. Genetic markers were determined by PCR sequence-speci c oligotyping. 3Department of Endocrinology and Diabetology, GasthuisZusters Antwerpen Campus Sint Augus- RESULTS tinus en Sint Vincentius, Antwerp, Belgium Unlike HLA-B*18 or -B*39, HLA-A*24 was associated with delayed progression from 4Department of Pediatrics, Universitaire Zieken- P huizen Leuven, Leuven, Belgium PATHOPHYSIOLOGY/COMPLICATIONS single- to multiple-autoantibody positivity ( = 0.009) but not to type 1 diabetes. 5 P < HLA-DQ2/DQ8 Department of Diabetology, Paola Kinderzie- This occurred independentlyfrom older age ( 0.001) and absenceof kenhuis, Antwerp, Belgium or -DQ8 (P < 0.001 and P = 0.003, respectively), and only in the presence of GAD 6Diabetology Clinic, Hopitalˆ Universitaire des autoantibodies. In contrast, HLA-A*24 was associated with accelerated progression Enfants Reine Fabiola, Brussels, Belgium 7 from multiple-autoantibody positivity to clinical onset (P = 0.006), but its effects Department of Diabetology, Universitair Zieken- huis Brussel, Brussels, Belgium wererestrictedtoHLA-DQ8+relativeswithIA-2orzinctransporter8autoantibodies P HLA-B*18, -B*39, Corresponding author: Else M. Balke, else.balke@ ( =0.002). but not was also associated with more rapid vub.be. HLA-DQ2 progression, but only in carriers with double positivity for GAD and insulin Received 27 November 2017 and accepted 20 autoantibodies (P =0.004). February 2018. This article contains Supplementary Data online CONCLUSIONS at http://care.diabetesjournals.org/lookup/suppl/ HLA-A*24 predisposes to a delayed antigen spreading of humoral autoimmunity, doi:10.2337/dc17-2462/-/DC1. whereas HLA-A*24 and -B*18 are associated with accelerated progression of © 2018 by the American Diabetes Association. advanced subclinical autoimmunity in distinct risk groups. The relation of these Readers may use this article as long as the work alleles to the underlying disease process requires further investigation. Their typing is properly cited, the use is educational and not for profit, and the work is not altered. More infor- should be relevant for the preparation and interpretation of observational and mation is available at http://www.diabetesjournals interventional studies in asymptomatic type 1 diabetes. .org/content/license. care.diabetesjournals.org Balke and Associates 1077 The asymptomatic phase of type 1 diabetes younger than age 40 years without pre- case of progression to diabetes, at clinical is signaled by circulating islet autoanti- selection for HLA-DQ–inferred risk or islet onset. BMI was expressed as an SD score bodies (autoAbs) (1). Its substaging by cell cytoplasmic autoAbs (ICAs). (BMI z score) by comparison with an age- biomarkers may shed light on the un- and sex-matched healthycontrol group (6). derlying disease process and its conceiv- RESEARCH DESIGN AND METHODS Analytical Methods able heterogeneity and thus contribute Participants IAA, GADA, IA-2A, and ZnT8A were deter- to risk assessment and selection for Between March 1989 and December 2015, mined by liquid-phase radiobinding assay, preventiontrials (2,3). The various autoAb the Belgian Diabetes Registry (BDR) using the99th percentileofhealthycontrol specificities tend to develop sequentially, consecutively recruited siblings and off- subjects as the cutoff (11). ZnT8A could be with those directed against insulin (insu- spring (,40 years of age at study entry) measured in all but one relative positive lin autoantibody [IAA]) or GAD65 (GAD an- of patients with type 1 diabetes according for at least one other autoAb, but only in a tibody [GADA]) usually appearing first, and to previously defined criteria (25). The fraction (8.7%; n = 546) of participants who those directedagainst islet antigen2 (IA- probands are considered representative tested negative for the other three autoAbs 2A) or zinc transporter 8 (ZnT8A) gener- of the Belgian patient population (25,26). (4,11,28). HLA-DQ, -A,and-B alleles were ally arising closer to clinical onset (3–5). After obtaining written informed consent typed by PCR sequence-specificoligonu- We and others have previously reported from each relative or their parents, a short cleotide dot-blot methods, as described that progression from single- to multiple- questionnaire with demographic, familial, previously (22,23,29). autoAb positivity occurs more rapidly and personal information was completed with younger age, presence of the HLA- at each visit. Blood samples were taken at Statistical Analysis DQ2/DQ8 high-risk genotype, or develop- study entry and, as a rule, yearly there- Statistical differences between groups were ment of IAA as the first autoAb (6–9). after. Only relatives with two or more analyzed with x2 or Fisher exact tests for In contrast, from the stage of multiple- contacts during the follow-up period (n = categorical variables and with the Mann- autoAb positivity onward, progression to 7,029), with the last contact being at Whitney U test for continuous data. clinical onset appears largely indepen- diagnosis in the case of progression to Kaplan-Meier analysis with the log-rank dent of age and HLA class II–inferred risk diabetes, were included in this study. The testwas used to assess progression from (6,9,10). Rather, the development of mul- median intervals between successive vis- the first autoAb+ sample to multiple- tiple autoAbs appears to signal a state its ranged between 11 and 13 months for autoAb positivity and from multiple- of advanced autoimmunity that almost the various groups of relatives studied (6). autoAb positivity to type 1 diabetes. When inevitably progresses to clinical onset within Diabetes was diagnosed according to multiple-autoAb positivity was assessed the next 20 years, with development of IA-2A the AmericanDiabetesAssociationcriteria(27). as the end point, follow-up ended at the or ZnT8A as indicators of an accelerated The study was conducted in accor- time of the first multiple-autoAb+ sample disease course (3,6,11–14). dance with the guidelines in the Declara- (before or at diagnosis of diabetes at the Although genome-wide association stud- tionofHelsinki,asrevisedin2013(accessed latest) or at the last single-autoAb+ sample ies have identified a large number of non- on 16 May 2017; https://www.wma.net/ (before or at diagnosis of diabetes at the HLA susceptibility loci for type 1 diabetes, policies-post/wma-declaration-of-helsinki- latest) (6). Follow-up for diabetes-onset HLA-DQ/DR genotypes and, to a lesser ethical-principles-for-medical-research- started at the time of the first multiple- degree, HLA class I alleles remain major involving-human-subjects/), and approved autoAb+ sample and ended at the last genetic risk determinants of the disease by the ethics committees of the BDR and contact with the relative or at clinical (15–20). Several reports have associated the participating university hospitals. onset, whichever came first. The baseline HLA-A*24, -B*18,and/or-B*39 with in- Random blood samples were collected variableslistedinTables1 and2were first creased disease risk, but their effects seem for sera and buffy coats, and aliquots entered in a univariate Cox regression largely restricted to carriers of specificHLA were stored at 280°C until analyzed for analysis model for predicting time to class II haplotypes (18,19,21–24). How- diabetes-associated and genetic markers, multiple-autoAb positivity or to diabetes, ever, the influenceofHLAclassIriskalleles respectively. All relatives were monitored re- and those with univariate P , 0.05 were on the various asymptomatic stages of gardless of their autoAbstatusandHLA-DQ entered in a multivariate model with type 1 diabetes and their relation to other genotype.Relativeswerenotprescreened respect of the Vittinghof criterion (at least biomarkers is overall less well documented for ICA nor were ICA results analyzed in 5–10 events per variable included) (30). than for HLA class II. The current study the current study. Initial autoAb positiv- Two-tailed statistical tests were performed therefore assessed the respective effect ity was defined as being persistent if the by SPSS for Windows version 24.0 soft- of HLA-A*24, -B*18,and-B*39 on sub- next sample was also positive for at least ware(IBM,Armonk,NY),andP , 0.05 was sequent stages of islet autoimmunity (i.e., one autoAb, regardless of