HLA-DQ8

HLA-DQ8 is a human leukocyte antigen (HLA) serotype within the HLA-DQ (DQ) class II antigen family. It is encoded by the HLA-DQA1 and HLA-DQB1 genes. HLA-DQ8 is one of the most studied HLA types due to its strong association with several autoimmune diseases.

Genetics

HLA-DQ8 is encoded by the alleles DQA1*03 and DQB1*03:02. These alleles are located on the short arm of chromosome 6 at position 6p21.3. The DQ8 molecule is a heterodimer consisting of an alpha chain (DQA1*03) and a beta chain (DQB1*03:02).

Function

The primary function of HLA-DQ8, like other HLA class II molecules, is to present antigens to CD4+ T cells. This process is crucial for the activation of the immune system and the initiation of an immune response. HLA-DQ8 is involved in the presentation of peptides derived from extracellular proteins.

Association with Diseases

HLA-DQ8 is strongly associated with several autoimmune diseases, including:

• Type 1 diabetes: HLA-DQ8 is one of the major genetic risk factors for type 1 diabetes. It is present in a significant proportion of individuals with the disease.
• Celiac disease: HLA-DQ8, along with HLA-DQ2, is associated with celiac disease. Individuals with these HLA types are at a higher risk of developing the disease.
• Rheumatoid arthritis: HLA-DQ8 has been implicated in the susceptibility to rheumatoid arthritis.

Clinical Relevance

The presence of HLA-DQ8 can be determined through genetic testing. This information can be useful in the diagnosis and management of autoimmune diseases. For example, in individuals with a family history of type 1 diabetes or celiac disease, the presence of HLA-DQ8 can indicate an increased risk of developing these conditions.

See Also

• HLA-DQ
• HLA-DQ2
• HLA-DQA1
• HLA-DQB1
• Autoimmune disease
• Type 1 diabetes
• Celiac disease
• Rheumatoid arthritis