Direct immunofluorescence can detect deposits of immunoglobulins and complement proteins in the patient's skin.

The complement proteins then create holes or pores in the invading organisms, leading to their destruction.

So far, researchers have identified and characterized the complement proteins and their suppressors.

"None of us had ever seen a complement protein before," Dr. Austen said.

When the blood detects organisms entering the body, it makes these complement proteins in its attack on the invaders.

When the blood detects organisms entering the body, these complement proteins are produced to attack the invaders.

To be sure that complement proteins do not turn against its own cells and organs, the body also makes a regulatory protein.

Patients naturally have different levels of complement proteins in their serum.

A known amount of standard complement proteins are added to the serum.

The complement proteins will react with these complexes and be depleted.