major histocompatibility complex, class II, DR3 Haplotypes groups DRA*01:DRB1*03:01 DRA*01:DRB1*03:02 DRA*01:DRB1*03:03 DRA*01:DRB1*03:04 Structure (See HLA-DR) Identifiers alpha *01:01 Symbol(s) HLA-DRA EBI-HLA DRA*01:01 Identifiers beta 1 *03:01 *03:01 *03:02 *03:03 *03:04 Symbol(s) HLA-DRB1 EBI-HLA DRB1*03:01 EBI-HLA DRB1*03:02 EBI-HLA DRB1*03:03 EBI-HLA DRB1*03:04 EBI-HLA DRB1*03:05 Shared data Locus chr.6 6p21.31

HLA-DR3 is composed of the HLA-DR17 and HLA-DR18 split 'antigens' serotypes. DR3 is a component gene-allele of the AH8.1 haplotype in Northern and Western Europeans. Genes between B8 and DR3 on this haplotype are frequently associated with autoimmune disease. Type 1 diabetes mellitus is associated with HLA-DR3 or HLA-DR4. Nearly half the US population has either DR3 or DR4 (only 1–3% have both), yet only a small percentage (about 0.5%) of these individuals will develop type 1 diabetes.

Serology + DR17 and DR3 recognition of some DRB1*03 allelesderived from IMGT/HLA DRB1* DR3 DR17 DR18 Sample allele % % % size (N) 03:01 33 64 0 9698 03:02 24 3 66 317 03:03 40 60 5 03:04 60 20 5 03:07 >50 1

Some DR3 also react with HLA-DR17 and/or HLA-DR18. The DRB1*03:04 primarily reacts with DR3. The serotypes of *03:05, *03:06, *03:08 to *03:31 are unknown.

Disease associations

By serotype HLA-DR3 is associated with early-age onset myasthenia gravis, Hashimoto's thyroiditis (along with DR5), primary sclerosing cholangitis, and opportunistic infections in AIDS, but lowered risk for cancers. It is also associated with membranous glomerulonephritis

By allele DRB1*03:01 (see HLA-DR17)

DRB1*03:02 (See HLA-DR18)

DRB1*03:04 is associated with Graves disease

By haplotypes DR3 and/or DQ2 is associated with Moreen's ulceration, "bout onset" multiple sclerosis, Graves' disease and systemic lupus erythematosus

DR3-DQ2 linkage is associated with coeliac disease, dermatitis herpetiformis, Diabetes mellitus type 1. DR3-DQ2 is the serological marker for HLA-DQ2.5cis isoform. Although it cannot identify the alpha ".5" chain of HLA DQ, DQA1*05:01 gene is almost always found within the DR3-DQ2 haplotype Eurasia (however in older studies DQA1*05:05 is commonly confused with DQA1*05:01)

Genetic linkage DR3 is genetically linked to HLA-DR52, DRB3*02:02 allele, and HLA-DQ2 (DQ2.5).

References