Ankylosing spondylitis (AS) is a form of chronic arthritis that causes pain and stiffness in the spine and other joints. Both men and women are affected by AS, although important sex differences exist: men are three times more likely to develop the disease, while women have slower disease progression and experience increased spinal pain. The reason for these apparent sex differences has remained a mystery until now.
A team of investigators led by Krembil Senior Scientist Dr. Robert Inman collected blood samples from male and female AS patients and then screened their blood for factors associated with the body’s immune response. A key feature of AS is activation of the immune system and consequent inflammation. Eric Gracey, an Immunology graduate student in Dr. Inman’s lab, found that levels of IL-17A proteins and Th17 cells, two factors that promote inflammation, were elevated in male AS patients.
Dr. Inman’s finding may lead to a paradigm shift in the development of treatment options for AS. “We have identified a clear difference in how the immune system is activated in male and female AS patients. It is vital that we use this new knowledge to specifically design more precise treatment options for each sex,” explains Dr. Inman.
This work was supported by the Canadian Institutes of Health Research, the Arthritis Research Centre and the Toronto General & Western Hospital Foundation.
Sexual dimorphism in the Th17 signature of ankylosing spondylitis. Gracey E, Yao Y, Green B, Qaiyum Z, Baglaenko Y, Lin A, Anton A, Ayearst R, Yip P, Inman RD. Arthritis & Rheumatology. 2015 Oct 16. [Pubmed abstract]