Testing for AxSpA: What's HLA-B27?
It was around 2010 that I was first starting to notice signs that something was "wrong" with me. Specifically, I was getting uveitis over and over again — my eyeball inflamed, bright red, painful as though it was literally within a cage inside my head, and allergic to any glimpse of light. It was one of the most painful experiences of my life, and to this day, my memory — in some response to trauma — can't exactly pinpoint or conjure the depth of pain.
If you haven't had uveitis, trust me when I tell you there were moments that made me pray to god (hint: I'm not religious). If you have, you probably know how it feels when your face and head feel like a ticking time bomb.
Seeing a specialist
It was sometime around the recurrent uveitis — after being neglected by doctors and told it was "contact irritation" and "poor diet," — that the phrase HLA-B27 came up. I was at a specialty eye hospital two states away at the request of my aunt (who also has ankylosing spondylitis, but was diagnosed even later than I was — in her 60s). She had recommended the hospital because she had (and recovered from) eye cancer.
The specialists threw around the words sarcoidosis, Lyme disease, multiple sclerosis, syphilis. I got X-rays and more blood tests. They pressed a spoon-like contraption to my eye, and I cried in the office. The doctors, slightly impatient with me, were confounded.
I'll be frank: at that point, I knew nothing about blood tests, health, immune-mediated diseases, and I generally thought that I was invincible. I was just 25. The idea that something was "wrong" with me was not something I was prepared to accept. Sickness was for other people. Sickness was an abstract. Sometimes I think back on that denial and ignorance and privilege; oh, how the Universe woke me up!
They then recommended an HLA-B27 test, which perhaps you've had. Mine came back to positive.
A little science lesson about HLA-b27
AxSpA (known as axial spondyloarthritis, a term for several types of inflammatory arthritis that cause problems with the spine and other joints) is associated with the human leukocyte antigen (HLA) gene known as HLA-B27. Ankylosing spondylitis (AS) specifically has a strong link to HLA-B27. There are actually almost 30 genes that are associated with AS or AxSpA conditions, but HLA-B27 is most common.
Human Leukocyte Antigens are a group of proteins that help to regulate immune function. They essentially tell the body, "This cell is good, and this cell is bad." In immune-mediated diseases, there is a mix-up in this communication.
About 90 percent of people with AxSpA conditions have the HLA-B27 gene.1 However, if you test positive for HLA-B27, it doesn't mean you will develop one of the conditions. It just increases your risk. On the flip side, testing negative for HLA-B27 doesn't mean you don't have AxSpA or AS. About 10 percent of people with AxSpA conditions test negative for HLA-B27. Also, if you have an immediate relative with the condition, it increases your risk as well.1
It's important to note that race can play into how HLA-B27 plays out (and no, it's not a white person's disease, contrary to misunderstanding). In African Americans, HLA-B27 is less prevalent, for example. This sort of information is crucial to ensuring people of all backgrounds get proper diagnoses and so patients can advocate for testing. When we are reductionist about diseases, people don't find relief — and marginalized patients are already at risk of not being given the care they deserve.
HLA-B27 was a clue into my AxSpA, but it wasn't the entire picture
After my test came back positive, I lost my insurance. Weirdly, my uveitis went away and I felt pretty healthy for some time. Besides serious fatigue (which I attributed to "life") and the occasional joint pain, I didn't have many AS symptoms. But I continued thinking about my HLA-B27 diagnosis, wondering what the hell it meant.
It took years to get really sick with AxSpA. During those years I found that my dad had AS, too, and that he'd actually had neck surgery for it when I was a kid. His is very mild, so perhaps that's why it never really came up. I also learned that my aunt had it too. Same family line.
Finally, when the pain became life-altering, I went to a rheumatologist. Two of them. Both of them diagnosed me with AS. They took into account the HLA-B27 test, but also my history of uveitis, my back pain, my mobility, and my inflammation levels (they tested my erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)).
It's important to remember that's there is no one test, and that HLA-B27 is only part of a whole picture. So, the next time you see the phrase HLA-B27 come up, I hope you'll know a little more about its place in the puzzle.
Can you tell when a flare is coming?