HLA B27 (Human Leukocyte Antigen B27) - PCR
Understanding HLA B27 (Human Leukocyte Antigen B27) - PCR
What is HLA B27 (Human Leukocyte Antigen B27) - PCR?
An HLA B27 (Human Leukocyte Antigen B27) - PCR test uses the Polymerase Chain Reaction (PCR) technique to detect the presence of the HLA B27 gene, a specific type of protein, on the surface of white blood cells. This gene is mainly associated with autoimmune and inflammatory conditions, such as ankylosing spondylitis.
Human Leukocyte Antigens (HLAs) genes play a crucial role in the immune system, and the HLA B27 variant is associated with certain autoimmune conditions, particularly seronegative spondyloarthropathies, a group of inflammatory rheumatic conditions, including ankylosing spondylitis, reactive arthritis, psoriatic arthritis, and juvenile idiopathic arthritis.
An HLA B27 (Human Leukocyte Antigen B27) - PCR test assists in the detection, disease risk assessment, and monitoring of these conditions. The Polymerase Chain Reaction (PCR) technique is more sensitive and specific than other techniques like flow cytometry, allowing for accurately identifying the HLA-B27 gene.
Your doctor may suggest an HLA B27 (Human Leukocyte Antigen B27) - PCR test if you exhibit signs and symptoms such as chronic back pain, joint pain, stiffness, or inflammation in the eyes, urethra, and joints or have a family history of autoimmune conditions. The HLA B27 test is also used to match donated tissue to the tissue of the organ transplant recipient.
Usually, no special preparation is needed for this test. You may eat and drink as per your daily routine. Talk to your doctor about your specific test results. Narrate your complete medical history to help them correlate your clinical and laboratory findings. The test results will help them determine your medical condition and formulate an overall treatment plan. However, the HLA B27 test results are not interpreted as proof of whether you have an autoimmune condition or not, whether they are positive or negative.
What is HLA B27 (Human Leukocyte Antigen B27) - PCR used for?
An HLA B27 (Human Leukocyte Antigen B27) - PCR test is done:
- If an individual exhibits symptoms of arthritis, such as chronic joint pain, stiffness, inflammation in the lower back, hips, neck, and chest, etc., or uveitis (painful inflammation of the eyes).
- In individuals with a family history of autoimmune diseases.
- Before an organ transplant procedure.
- To monitor disease and treatment progress in individuals with pre-existing autoimmune disorders.
What does HLA B27 (Human Leukocyte Antigen B27) - PCR measure?
An HLA B27 (Human Leukocyte Antigen B27) - PCR test is used to determine the presence or absence of HLA B27 antigen to rule out the possibility of an autoimmune disorder. The presence of HLA-B27 protein on the surface of white blood cells is often associated with autoimmune disorders. A positive result is associated with an increased risk of developing certain autoimmune conditions, particularly ankylosing spondylitis, reactive arthritis, and psoriatic arthritis. A negative result suggests the absence of the HLA-B27 gene variant. However, it does not rule out the possibility of developing an autoimmune disorder, as not all affected individuals carry the HLA-B27 gene.
Interpreting HLA B27 (Human Leukocyte Antigen B27) - PCR results
Interpretations
RESULT |
REMARKS |
Negative |
No expression of HLA B-27 |
Indeterminate |
Grey zone (within 10 channels of cutoff) |
Positive |
Expression of HLA B-27 detected |
Anti-HLA-B27 antibody cross-reacts with several other antigens of the HLA-B group, specially HLA-B7, leading to false-positive results*