Can HLA B27 Change From Positive To Negative?
Have you or anyone you know experienced this? After having a positive HLA-B27 test, has it tuned to negative or vice versa?
Technically speaking, a positive HLA b27 can never turn negative and vice versa. The reason for this is, HLA-b27 is a genetic marker and this works like a blood group, which never changes. So, what seemingly makes a HLA b27 change from positive to negative? To understand this you need to understand the method of testing HLA-B27 gene.
The HLA-B27 test is done using three different ways:
- Flow Cytometry (FC)
- Micro lymphocytotoxicity (MLCT)
- DNA based typing with the use of Polymerase chain reaction based assays (PCR).
The PCR based method is the most accurate of all the tests for HLA B27 testing. (1) Some patients who have tested negative using the flow cytometry method have a positive result when tested using the PCR method.(1)
Flow cytometry test can also give inconclusive report, which needs to be checked again using the PCR based method. So, this is the reason how a positive HLA b27 can turn negative and vice versa and the reason of the discrepancy in the tests.
So, it is important to look into the method of the tests used when you are getting HLA B27 checked, as the chosen method can be responsible for the result of false positive and vice versa.
Are You Born With HLA B27?
Yes, HLA B27 is present from birth, as it is a genetic variability. Having HLA B27 increases the risk for certain diseases.(2) HLAs or human leukocyte antigens are proteins that are present on white blood cells and help the body’s immune system differentiate between foreign substances and healthy body tissue that can cause infection in the body.
Majority of the HLAs help in protecting your body; however, this particular HLA-B27 is a protein that leads to dysfunction in the immune system.(4) The HLA-B27 present on the white blood cells can result in the body’s immune system attacking the healthy cells resulting in immune-mediated disease or an autoimmune disease, such as ankylosing spondylitis or juvenile rheumatoid arthritis.(2, 3)