Human Leukocyte Antigen (HLA) B27, PCR TEST
The Human Leukocyte Antigen (HLA)-B27 blood test, a polymerase chain reaction (PCR)-based assessment, aims to detect the presence of the HLA-B27 gene responsible for encoding the HLA-B27 protein. This protein lies on the surface of specialized white blood cells, known as antigen-presenting cells, that aid the body's immune system to distinguish between "self" and "nonself."
HLA-B27 has several variants present in the general population. However, in less than 8% of individuals, some HLA-B27 variants are strongly associated with ankylosing spondylitis and a spectrum of chronic inflammatory conditions referred to as spondyloarthropathies.
In the HLA-B27 PCR test, HLA is a biomarker for diagnosing and monitoring these aforesaid conditions.
What is HLA-B27 PCR Used For?
An HLA-B27 PCR is done:
To evalute the risk of developing HLA-B27 related diseases in individuals with symptoms of arthritis and other inflammatory conditons
To diagnose individuals with a family history of autoimmune disorders
Prior to an organ or tissue transplantation
To monitor disease and treatment progress in individuals with pre-existing inflammatory or autoimmune conditions
Symptoms related to HLA-B27 Associated Diseases
The symptoms of HLA-B27-related diseases, depending on the specific condition, can vary. So, your doctor may order an HLA-B27 PCR test if you have symptoms of:
Stiffness and swelling of joints near the neck, chest, hip, and spine
Chronic joint pain that improves with exercise
Extreme tiredness
Inflammation in the eye
Skin rash or psoriasis
Abdominal pain
Diarrhoea or loose stools
Preparation for Test
No special steps are to be taken to prepare for this test.
Interpretation of Test Results
Interpretation of HLA-B27 PCR is as follows:
Positive result(Abnormal)
This result means an expression of the HLA-B27gene variant in the sample, indicating a greater than average risk of developing or having autoimmune conditions- like ankylosing spondylitis, reactive arthritis, and psoriatic arthritis.
Negative result(Normal)
It means the absence of the HLA-B27 variant in the blood sample. It does not, however, preclude future development of the autoimmune disorder.
FAQs
Are there any risks associated with the HLA B27 test?
The HLA-B27 test is a safe procedure. However, some common risks involved during the blood collection include mild pain, bruising, or bleeding at the injection site. It usually takes a day or two for these symptoms to go away. A serious complication is rare.
When To Get Tested?
Males in their early 30s must be tested immediately if they exhibit arthritis symptoms, such as chronic joint pain, stiffness, and inflammation, especially in the lower back, chest, hips, and neck, or eye pain.
Should I be tested for HLA-B27 if I have a family history of HLAB27-associated autoimmune diseases?
In the case of autoimmune disorders running in your family, you should consult your doctor to determine your risk of developing one through a HLA-B27 test. This test will surely clear the air for you.
Is it possible to have a positive HLA B27 and not have any disease?
Yes, having a positive HLA B27 without any specific disease is possible. Some individuals have the HLA B27 genes in their DNA but never develop an associated disease.
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