Key first steps to inflammatory arthritis identified

In an advance that may lead to new therapies to treat inflammatory arthritis, scientists have identified the initial steps leading to joint inflammation using a novel approach for imaging movement of immune cells in living animals.

Researchers found that expression of a specific molecule – complement C5a – is required to cause the immune cells called neutrophils to adhere to joint surfaces and migrate into the joint, a process known to set off the inflammatory cascade. “Inflammatory arthritis is caused when immune cells are recruited from the blood into the joint in a highly regulated process controlled by chemoattractants and adhesion receptors,” said Andrew Luster from the Massachusetts General Hospital (MGH) in the US.