View Full Version : C3 and C4 levels on Immunosuppression

09-30-2013, 12:38 PM
I just had some labs done for a follow up with dr next week. I will be speaking to her about this but thought maybe someone here could shed some light.

C3 my level 85 standard range 81-225
C4 8.8 10-40

C3 97
C4 9

C3 73
C4 7

My latest lab shows the lowest thus far. I started cellcept in Dec. switched to myfortic. From what I understood please correct me if I'm wrong low c3 and c4 are typically low with active lupus? I thought the purpose of taking cellcept or something alike was to get it under control ie non active/ remission? Now I understand it takes some time to see results but as I mentioned they are the lowest thus far. I know they take in to account other factors but is this test telling me my lupus is active? I mentioned in an earlier post about ra and lupus. My joints have been hurting ( hands knees groin big toe joints ) . Since the weather has changed my body feels as though it has rusted up. I feel so stiff. I don't know I thought I'd be feeling better this winter? Summer was okay for me I was feeling pretty good. Does the c3/c4 reflect how you feel?

09-30-2013, 04:06 PM
The complement system is a set of blood proteins that are circulating, acting as mediators of the body's inflammatory response. They act especially in the destruction of viruses and bacteria. The complement system does not require previous exposure to a microorganism like antibodies do. It also does not keep a memory of encounters the way antibodies do. Antibodies also need time to be generated, the complement system does not. For these reasons the complement system is a very important part of the immune system and imbalances can adversely affect the integrity and function of the immune system.
Since the complement system is used by the body to help clear immune complexes from the blood, it can be used to monitor activity in Lupus, particularly with glomerulonephritis and vasculitis.
Normal levels vary based on a number of factors including gender, age, and the lab doing the testing. Here is a basic guideline:
C3 - males: 88 to 252 mg/dl (880 to 2520 mg/L)
females: 88 to 206 mg/dl (880 to 2060 mg/L)
C4 - males: 12 to 72 mg/dl (120 to 720 mg/L)
females: 13 to 75 mg/dl (130 to 750 mg/L)
You are correct in feeling that low complement levels in Lupus usually means increased disease activity. When the body uses the complement system to clear immune complexes from the blood it results in low complement levels. Essentially, the complement proteins are not being produced as quickly as they are being used. This test is done to monitor the level of your activity in Lupus as well as to aid in diagnosing Lupus.
I hope that I have answered your question. Please let me know if you need anything further.

Peace and Blessings

09-30-2013, 04:34 PM
Nothing I can add to that. Thank you Susie!

09-30-2013, 07:06 PM
Thank you Susie. So 9 months almost 10 months of cellcept/myfortic and still active lupus. I thought by now it would be better.

10-06-2013, 10:06 AM
Is it possible to diagnosed with Lupus based on just low complements alone? That is low complements outside the reference range but no positive SLE antibodies (DS-DNA, Smith, RNP, phospholipids, etc.)? Say, in the case of someone with Sjogren's (SSA/SSB)? Or do you have to go down the list and match symptoms with SLE and/or Sjogren's? Thanks.

[FONT=times new roman,times,serif][SIZE=4]This test is done to monitor the level of your activity in Lupus as well as to aid in diagnosing Lupus.
I hope that I have answered your question. Please let me know if you need anything further.

10-07-2013, 10:38 AM
Hello newfangled. I'm sorry but I can't answer your question. I only know my dr said after my first labs were done that low c4 and c3 were markers for lupus. Maybe post as a separate question. You may get more answers. Good luck and take care.