i am a 49 yo female, mom, wife, nurse and am "being treated for lupus"-over the past 2 years. despite being on vioxx, plaquinel,prednisone and imuran, my complements-c3 and c4 have continued to plummet. i don't have a +ANA, but have flares almost monthly. what can you tell me about complements? getting a second opinion this week. this diseasse is really playing havoc with my life
Here is what I've been able to find out about Serum Complement. C3 is the test that measures the concentration of a component of complements in the blood. The complement system, which is a part of the body's overall defense operation, is a series of proteins that act as "backup" for the activity of antibodies. When antibodies attack antigens (a substance that provokes the body's immune system to produce antibodies), they form entities called immune complexes, which cause inflamation and some tissue damage. Immune complexes attract the complement-system components, which move in to destroy the membranes of the "enemy" cells by summoning phagocytes (cell eaters) to the area, coating the cell walls with a substance phagocytes can "recognize" and producing solvents to destroy the membranes.
There are only a certain amount of complements in the body. So, if complements have been drawn to the sites of immune complex activity, there will be lower than normal levels of complements in the general circulation. In active Lupus, these complement levels are generally low. The level of complements are used in monitoring the disease and in treatment of the disease.
I hope that I answered your question! At least I learned something myself in researching for you :-)
Peace and Blessings