HLA-DR4

HLA-DR4 is a human leukocyte antigen serotype within HLA-DR serogroup. The serotype is determined by the antibody recognition of HLA-DRB1*04 and 36 related alleles. HLA-DR4 and HLA-DRB1*04 are associated with several autoimmune conditions, including rheumatoid arthritis, type 1 diabetes, and pemphigus vulgaris.

Structure and Function

HLA-DR4 is a part of the Major Histocompatibility Complex (MHC) class II molecules, which are expressed in antigen-presenting cells (APCs). The primary function of these molecules is to present processed antigenic peptides to T cells. HLA-DR4, like other MHC class II molecules, is a heterodimer consisting of an alpha (DRA) and beta chain (DRB), the latter being encoded by HLA-DRB1*04 alleles in the case of HLA-DR4.

Disease Associations

HLA-DR4 is associated with several autoimmune diseases.

• Rheumatoid Arthritis: HLA-DR4 is one of the most significant genetic risk factors for rheumatoid arthritis. The presence of HLA-DR4 is associated with increased disease severity.

• Type 1 Diabetes: HLA-DR4, along with HLA-DR3, is commonly found in patients with type 1 diabetes. These alleles are thought to contribute to disease susceptibility by presenting autoantigenic peptides to T cells.

• Pemphigus Vulgaris: HLA-DR4 is also associated with an increased risk of pemphigus vulgaris, a rare autoimmune blistering skin disease.

See Also

• Human leukocyte antigen
• Major Histocompatibility Complex
• Rheumatoid arthritis
• Type 1 diabetes
• Pemphigus vulgaris

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