Ankylosing spondylitis is associated with which HLA antigen?

Ankylosing spondylitis (AS) is primarily associated with the HLA-B27 antigen. This association is significant because a large percentage of individuals with ankylosing spondylitis express this particular human leukocyte antigen. The presence of HLA-B27 is thought to be a predisposing genetic factor for the disease, which is considered an autoimmune condition primarily affecting the spine and sacroiliac joints.

The link between HLA-B27 and ankylosing spondylitis involves an abnormal immune response to certain triggers, possibly involving molecular mimicry, where the immune system mistakenly targets the body’s own tissues after being triggered by infection or other environmental factors. This leads to the characteristic symptoms of AS, including chronic back pain and stiffness that typically improve with exercise.

In contrast, the other HLA antigens listed—HLA-DR4, HLA-A1, and HLA-DQ2—are associated with different conditions. HLA-DR4 is commonly linked to rheumatoid arthritis, HLA-A1 is associated with various autoimmune diseases, and HLA-DQ2 is notably related to celiac disease. Therefore, these antigens do not have the same established connection to ankylosing spondylitis as