immune

response

eXit

New Directions

Can an immune response
be rerouted to treat disease?

by Margaret Wahl

What do inflammatory muscle diseases (myositis), myasthenia gravis, Lambert-Eaton syndrome, and dozens of other disorders like lupus and rheumatoid arthritis, have in common?

In all these and more, the body’s immune system, which normally detects and destroys invading microbes that cause illness, somehow has taken a wrong turn, and is attacking its own tissues, causing what’s known as an “autoimmune” (self-immune) disease.

In myositis, the target is mostly muscle fibers. In myasthenia gravis, it’s the parts of muscle cells that normally receive signals from nerve cells (the acetylcholine receptors), and in Lambert-Eaton syndrome, it’s the parts of nerve cells that signal muscle cells.

But it’s not only the targets of the immune system that differ among the various autoimmune disorders. These disorders also differ with respect to which part of the immune system predominates in causing the problem and what kind of solution might work best for solving it.

HigHway patrol

The first step in any immune response is the perception of a threat (real or not) by specialized cells called macrophages (“big eaters”) and dendritic (branching) cells.

These cells patrol the body’s highways and can approach an invader, usually a microbe, such as a bacterium, and engulf it. They then digest its proteins and display pieces of them on the