HLA class II haplotypes differentiate between the adult autoimmune polyglandular syndrome types II and III

Genetics of the adult autoimmune polyglandular syndrome (APS) is poorly understood.

The aim of this study was to gain further insight into the genetics of the adult APS types. SITE: The study was conducted at a university referral center.

The human leukocyte antigen (HLA) class II alleles, haplotypes, and genotypes were determined in a large cohort of patients with APS, autoimmune thyroid disease (AITD), and type 1 diabetes and in healthy controls by the consistent application of high-resolution typing at a four-digit level.

Comparison of the allele and haplotype frequencies significantly discriminated patients with APS vs AITD and controls. The HLA class II alleles DRB1*03:01 *04:01, DQA1*03:01, *05:01, DQB1*02:01, and *03:02 were observed more frequently (P<.001) in APS than in AITD and controls, whereas the alleles DRB1*15:01, DQB1*03:01, and *06:02 were underrepresented in APS vs AITD (Pc<.001) and controls (Pc<.01), respectively. The DRB1*03:01-DQA1*05:01-DQB1*02:01 (DR3-DQ2) and DRB1*04:01-DQA1*03:01:DQB1*03:02 (DRB1*04:01-DQ8) haplotypes were overrepresented in APS (Pc<.001). Combination of both haplotypes to a genotype was highly prevalent in APS vs AITD and controls (Pc<.001). Dividing the APS collective into those with Addison's disease (APS type II) and those without Addison's disease but including type 1 diabetes and AITD (APS type III) demonstrated DR3-DQ2/DRB1*04:01-DQ8 as a susceptibility genotype in APS III (Pc<.001), whereas the DR3-DQ2/DRB1*04:04-DQ8 genotype correlated with APS II (Pc<.001). The haplotypes DRB1*11:01-DQA1*05:05-DQB1*03:01 and DRB1*15:01-DQA1*01:02-DQB1*06:02 are protective in APS III but not in type II (Pc<.01).

HLA class II haplotypes differentiate between the adult APS types II and III. Susceptible haplotypes favor the development of polyglandular autoimmunity in patients with AITD.