HLA-B7

HLA-B7 is a human leukocyte antigen (HLA) serotype within the HLA-B locus. The serotype identifies the gene products (proteins) of the HLA-B*07 allele group. HLA-B7 is one of the most common HLA-B alleles in many populations and has been extensively studied in relation to its role in the immune system and its association with various diseases.

Structure and Function

HLA-B7 is a class I major histocompatibility complex (MHC) molecule. It is composed of a heavy chain (alpha chain) and a light chain (beta-2 microglobulin). The heavy chain is encoded by the HLA-B gene located on chromosome 6. The primary function of HLA-B7, like other class I MHC molecules, is to present endogenous peptides to cytotoxic T cells (CD8+ T cells). This process is crucial for the immune system to recognize and eliminate infected or malignant cells.

Genetics

The HLA-B7 serotype corresponds to the HLA-B*07 allele group. This group includes several alleles, such as HLA-B*0702, HLA-B*0703, and others. These alleles differ by a few amino acids in the peptide-binding region, which can influence the repertoire of peptides they present and their interaction with T cell receptors.

Disease Associations

HLA-B7 has been associated with various diseases, including:

• Ankylosing spondylitis
• Psoriasis
• Reactive arthritis
• HIV progression

The presence of HLA-B7 can influence the susceptibility to these diseases and the course of the disease. For example, individuals with HLA-B7 may have a different progression rate of HIV infection compared to those without this allele.

Population Distribution

The frequency of HLA-B7 varies among different populations. It is relatively common in European populations and less frequent in Asian and African populations. The distribution of HLA-B7 and other HLA alleles is of interest in population genetics and anthropology.

Clinical Relevance

HLA typing, including HLA-B7, is important in several clinical contexts:

• Organ transplantation: Matching HLA alleles between donors and recipients can reduce the risk of transplant rejection.
• Bone marrow transplantation: HLA matching is critical for the success of bone marrow transplants.
• Disease risk assessment: Identifying HLA-B7 can help in assessing the risk for certain autoimmune diseases and infections.

See Also

• HLA-B
• HLA-A
• HLA-C
• Major histocompatibility complex
• Human leukocyte antigen