Immune cell study sheds new light on how inflammatory arthritis begins
Published on 25 January 2017
A new study examining the movement of immune cells has led to new insights into how the biological processes that lead to inflammatory arthritis get started.
The research from Massachusetts General Hospital used a novel approach for imaging the movement of immune cells in living animals, and could pave the way for new methods of treating the disease.
How joint inflammation commences
Inflammatory arthritis occurs when immune cells from the blood are chemically drawn into the joint, attacking healthy tissue to cause pain and inflammation. When the disease reaches a symptomatic stage, it is often difficult to determine the initial steps that set off the process.
This study, published in the medical journal Science Immunology, used multiphoton intravital microscopy - an imaging technology that allows immune cell movements to be tracked in real time - to follow the development of arthritis in lab mice with rheumatoid arthritis, in order to better understand how this works.
It was revealed that the presence of immune complexes within the joint space leads to the production of a molecule called C5a, which is then displayed on the inner walls of adjacent blood vessels and causes immune cells called neutrophils to pass into the joint, setting off the process of inflammation.
The implications for treatment
Understanding the biological functions involved in triggering inflammatory arthritis could prove instrumental in future efforts to design therapies that interrupt this process by shutting down crucial steps.
The team is now looking to carry out further research to gain a better view of how this process works and to determine whether other types of immune cell may also be involved.
The study's senior author Dr Andrew Luster, chief of Massachusetts General Hospital's division of rheumatology, allergy and immunology, said: "The control of immune cell entry into the joint represents a major point at which new therapies could be developed to reduce the symptoms of inflammatory arthritis."
Arthritis Research UK's view
Dr Natalie Carter, head of research liaison and evaluation, said: "This study will help us gain a better understanding of how inflammation begins in the body and could lead to more effective treatment and earlier diagnosis of arthritis.
"Inflammatory arthritis is an autoimmune disease that attacks what it means to live. We fund research to find better treatments and gain more insight into this painful condition, allowing effective treatment to begin much earlier than before.
"However, we need to continue to carry out research to understand where and why arthritis starts and how immune cells can be controlled in the early stages of inflammatory arthritis so we can do more to overcome the pain, isolation and fatigue that it causes.
"This is the focus of our flagship Arthritis Research UK Rheumatoid Arthritis Pathogenesis Centre of Excellence, where we have invested £2.5 million into understanding the causes of rheumatoid arthritis."