Imagine superheroes who can destroy their enemies by engulfing them whole, acquire new powers to ward off unfamiliar threats and enlist the help of others when the going gets tough.
To find such superheroes, you’d have to look no further than your own body. Monocytes—the largest cells circulating in the blood—have all of these capabilities and more. They patrol the blood for disease-causing bacteria and viruses and use their ‘special powers’ to eliminate them.
Dr. Nigil Haroon, a Scientist at Krembil Research Institute, has recently shown that instead of fighting disease, some monocytes contribute to it. He and his team have found evidence suggesting that some monocytes worsen the symptoms of ankylosing spondylitis (AS)—a form of spinal arthritis.
AS is characterized by inflammation, stiffness of the spine and chronic back pain. Unusually, over half of those with the condition also have gut inflammation. Researchers have been trying to understand the mechanisms behind this puzzling connection.
By analyzing spinal tissues of AS patients who have gut inflammation, Dr. Haroon’s team made a startling discovery: while patrolling for threats in the gut, some monocytes pick up information that causes them to travel to the spine where they promote inflammation.
“It’s as if these monocytes were tricked into overreacting, thus exacerbating the symptoms of AS,” explains Dr. Francesco Ciccia, who led the study with Dr. Haroon.
“Our results suggest that monocytes from the gut could play an important role in AS pathogenesis. Moreover, they’re providing new insight into the complex relationship between AS and gut inflammation, one factor at a time,” comments Dr. Haroon. “Our goal is to eventually develop specific drugs to help alleviate the symptoms in these patients.”
This work was supported by the Italian Ministero dell’Istruzione, dell’Università e della ricerca Scientifica and the Toronto General & Western Hospital Foundation.
Ciccia F, Guggino G, Zeng M, Thomas R, Ranganathan V, Rahman A, Alessandro R, Rizzo A, Saieva L, Macaluso F, Peralta S, Di Liberto D, Dieli F, Cipriani P, Giacomelli R, Baeten D, Haroon N. Pro-inflammatory CX3CR1+ CD59+ TL1A+ IL-23+ monocytes are expanded in patients with Ankylosing Spondylitis and modulate ILC3 immune functions. Arthritis Rheumatol. 2018 June 5. doi: 10.1002/art.40582.
Dr. Nigil Haroon, Scientist, Krembil Research Institute. Photo courtesy of the Globe and Mail.