Quidel Corp. announced Tuesday that it has launched for research applications its C3aenzyme immunoassay for detecting one of the components of the complement system, C3a.

The complement system plays an integral role in the human immune system. The C3acomponent is an activation fragment of the plasma complement protein C3, and is known tocause an acute inflammatory response. The inappropriate activation of complement in autoimmune diseases is thought to contribute to disease progression, as well.

"C3a is one of the hot new markers" for researchers who study the complementcascade, explained Mark Francois, manager of investor relations at Quidel (NASDAQ:QDEL).

This is the fifth test the San Diego company has developed for detecting complementsplit proteins; the others detect the components C4d, Bd, SCb5-9 and iC3b, Francois said.Although the current immunoassays are for research purposes only, Quidel is "about tostart one clinical study to look at the utility of these markers to predict the onset ofautoimmune diseases -- especially systemic lupus erythematosus -- and flare-ups,"Francois told BioWorld.

-- Jennifer Van Brunt