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Published on: 2/4/2026

Ankylosing Spondylitis (AS): Symptoms, HLA-B27 Testing, and Biologics

Ankylosing spondylitis usually causes chronic lower back pain lasting more than 3 months with morning stiffness that improves with movement, and may also involve hips, chest, heels, fatigue, or eye inflammation. HLA-B27 testing can support the diagnosis but does not confirm or exclude it, so doctors combine symptoms with MRI or X-rays and blood tests, and treat with exercise and physical therapy first, then consider biologics such as TNF or IL-17 inhibitors for ongoing inflammation, balancing benefits with infection risks and screening needs. There are several factors to consider; see below for key details that can affect your next steps.

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Explanation

Ankylosing Spondylitis (AS): Symptoms, HLA-B27 Testing, and Biologics

Ankylosing Spondylitis (AS) is a long-term inflammatory condition that mainly affects the spine and the joints where the spine meets the pelvis. Over time, ongoing inflammation can lead to stiffness, pain, and reduced flexibility. While AS is a serious medical condition, many people live full and active lives with early diagnosis, appropriate treatment, and regular medical care.

This guide explains Ankylosing Spondylitis in clear, practical language, focusing on symptoms, HLA-B27 testing, and modern treatments such as biologic medications.


What Is Ankylosing Spondylitis?

Ankylosing Spondylitis is part of a group of conditions called axial spondyloarthritis, which primarily affect the spine. AS is considered an autoimmune or immune-mediated disease, meaning the immune system mistakenly triggers inflammation in the joints.

Over time, repeated inflammation can cause parts of the spine to fuse. This does not happen to everyone, and modern treatments have greatly reduced the risk of severe progression.

AS most often begins:

  • In late teens or early adulthood
  • Before age 45
  • More commonly in males, though females are often underdiagnosed

Common Symptoms of Ankylosing Spondylitis

Symptoms of Ankylosing Spondylitis usually develop gradually. They can vary widely from person to person and may come and go.

Early and Common Symptoms

  • Chronic lower back pain lasting more than 3 months
  • Morning stiffness that improves with movement
  • Pain that improves with exercise but not with rest
  • Discomfort in the hips or buttocks
  • Fatigue that does not fully improve with sleep

Symptoms Beyond the Spine

AS can affect other parts of the body, including:

  • Neck pain and reduced neck movement
  • Chest tightness due to rib joint inflammation
  • Heel pain (from tendon or ligament inflammation)
  • Shoulder or knee pain

Other Possible Features

  • Eye inflammation (uveitis) causing redness, pain, or blurred vision
  • Digestive symptoms, sometimes linked with inflammatory bowel disease
  • Skin changes, such as psoriasis in some people

If symptoms like severe chest pain, vision changes, or weakness occur suddenly, it is important to speak to a doctor right away, as these may require urgent medical attention.


Why Early Diagnosis Matters

Early diagnosis of Ankylosing Spondylitis allows treatment to begin before permanent joint damage occurs. Delayed diagnosis is common because early symptoms can look like routine back pain.

Starting treatment early can:

  • Reduce pain and stiffness
  • Preserve posture and mobility
  • Lower the risk of spinal fusion
  • Improve quality of life

If you are unsure whether your symptoms may fit AS, you might consider doing a free, online symptom check for Medically approved LLM Symptom Checker Chat Bot. This can help you decide whether it’s time to discuss your symptoms with a healthcare professional.


Understanding HLA-B27 Testing

What Is HLA-B27?

HLA-B27 is a genetic marker found on the surface of white blood cells. It plays a role in how the immune system recognizes threats.

How Is HLA-B27 Related to Ankylosing Spondylitis?

  • About 80–90% of people with AS test positive for HLA-B27
  • However, most people with HLA-B27 never develop AS
  • Some people with AS are HLA-B27 negative

This means HLA-B27 testing is helpful but not definitive.

When Is HLA-B27 Testing Used?

Doctors may order this test if:

  • Back pain started at a young age
  • Pain improves with movement
  • Imaging results are unclear
  • There are symptoms outside the spine (like eye inflammation)

Important Limitations

  • A positive test does not confirm AS by itself
  • A negative test does not rule it out

Diagnosis is based on a combination of:

  • Medical history
  • Physical exam
  • Imaging (X-rays or MRI)
  • Blood tests including inflammation markers

Always discuss test results with a doctor who can interpret them in the full clinical context.


Imaging and Other Tests

In addition to HLA-B27 testing, doctors may use:

  • MRI scans to detect early inflammation
  • X-rays to look for structural changes
  • Blood tests such as CRP or ESR to measure inflammation

MRI is especially useful early in the disease, before permanent changes appear on X-rays.


Treatment Options for Ankylosing Spondylitis

There is no cure for Ankylosing Spondylitis, but modern treatment can control symptoms and slow progression.

Non-Medication Approaches

These are important for everyone with AS:

  • Regular exercise and stretching
  • Physical therapy
  • Posture training
  • Smoking cessation

Movement is essential—rest alone often worsens stiffness.


Biologics and Ankylosing Spondylitis

What Are Biologics?

Biologics are advanced medications that target specific parts of the immune system involved in inflammation.

They are usually considered when:

  • Symptoms remain active despite other treatments
  • Imaging shows ongoing inflammation

Common Types of Biologics Used in AS

  • TNF inhibitors (block tumor necrosis factor)
  • IL-17 inhibitors (block interleukin-17)

These medications have been studied extensively and are recommended by major rheumatology organizations.

Benefits of Biologics

  • Significant reduction in pain and stiffness
  • Improved daily function
  • Better sleep and energy levels
  • Reduced inflammation on imaging

Possible Risks and Side Effects

Biologics suppress part of the immune system, which can:

  • Increase infection risk
  • Require screening for tuberculosis or hepatitis
  • Cause injection or infusion reactions

These risks are real but manageable when monitored closely. For many patients, the benefits outweigh the risks. A doctor will help decide what is appropriate based on your health history.


Living Well With Ankylosing Spondylitis

Many people with Ankylosing Spondylitis work, exercise, raise families, and maintain active social lives. Ongoing care makes a meaningful difference.

Helpful strategies include:

  • Keeping regular medical appointments
  • Taking medications as prescribed
  • Staying physically active
  • Addressing mental health and fatigue
  • Seeking support when needed

If you notice new or worsening symptoms, or if something feels serious or life-threatening, speak to a doctor immediately.


When to Talk to a Doctor

You should consider speaking to a healthcare professional if you have:

  • Back pain lasting more than 3 months
  • Morning stiffness that improves with movement
  • Family history of Ankylosing Spondylitis
  • Eye pain or sudden vision changes
  • Unexplained fatigue or joint pain

If you are unsure how your symptoms fit together, a free, online symptom check for Medically approved LLM Symptom Checker Chat Bot may help guide your next steps—but it should never replace professional medical advice.


Final Thoughts

Ankylosing Spondylitis is a lifelong condition, but it is manageable. Advances in early diagnosis, imaging, and biologic therapies have transformed outcomes for many people. Understanding symptoms, knowing the role of HLA-B27 testing, and learning about modern treatments empowers you to take an active role in your health.

If you have concerns, questions, or symptoms that could be serious, always speak to a doctor. Early care can make a lasting difference.

(References)

  • * Sieper, J., & Poddubnyy, D. (2017). Ankylosing Spondylitis. *The New England Journal of Medicine*, 376(13), 1265-1271. https://pubmed.ncbi.nlm.nih.gov/28350619/

  • * van der Heijde, D., Ramiro, S., Landewé, R., et al. (2019). 2019 update of the ASAS/EULAR recommendations for the management of axial spondyloarthritis. *Annals of the Rheumatic Diseases*, 78(10), 1297-1306. https://pubmed.ncbi.nlm.nih.gov/31331908/

  • * Baraliakos, X., & Braun, J. (2020). Biological Treatments in Spondyloarthritis: An Update. *Current Rheumatology Reports*, 22(8), 34. https://pubmed.ncbi.nlm.nih.gov/32468307/

  • * Ciccia, F., & Guggino, G. (2022). HLA-B27: From Genetics to Pathophysiology. *Frontiers in Immunology*, 13, 856525. https://pubmed.ncbi.nlm.nih.gov/35250682/

  • * Poddubnyy, D., & van der Heijde, D. (2023). Ankylosing spondylitis: recent insights and future perspectives. *The Lancet Rheumatology*, 5(2), e93-e104. https://pubmed.ncbi.nlm.nih.gov/36738914/

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