• Welcome to Phoenix Rising!

    Created in 2008, Phoenix Rising is the largest and oldest forum dedicated to furthering the understanding of and finding treatments for complex chronic illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia (FM), long COVID, postural orthostatic tachycardia syndrome (POTS), mast cell activation syndrome (MCAS), and allied diseases.

    To become a member, simply click the Register button at the top right.

C3 and C4 complement levels in MCAD?

Thinktank

Senior Member
Messages
1,640
Location
Europe
@TrixieStix , did the consultation and testing by the immunologist lead to something?

I just received my labs and C3 + C4 are now low. ANA and ENA panels were negative.
I can't find much info if there's any relationship between low complement levels and MCAS.
 

TrixieStix

Senior Member
Messages
539
@TrixieStix , did the consultation and testing by the immunologist lead to something?

I just received my labs and C3 + C4 are now low. ANA and ENA panels were negative.
I can't find much info if there's any relationship between low complement levels and MCAS.

I have low C3 and low CH50 (my C4 is normal). The immunologist thinks I have a genetic partial C3 deficiency, but I actually think he may be wrong about this because genetic C3 deficiency is quite rare. From what I've learned from reading about complement deficiencies and from talking to a few people with genetic complement deficiency it seems to me that it's much more likely that I have a genetic deficiency of either Factor H or Factor I. Either will result in low C3 as a downstream effect.

The immunologist referred me to a doctor who is a medical school professor and who is much more knowledgeable about complement deficiencies. I see this new doctor on November 2nd. He specializes in both immunodeficiency & rheumatology. I was told he is already aware of my case and has some further tests that he would like to run. I will for sure be requesting that Factor H and Factor I be tested.

In terms of your low C3 and C4, having both low C3 and C4 is most often associated with various immune complex diseases rather than genetic complement deficiency. Lupus is not the only immune complex disease that can cause this. For example a negative ANA does not rule out Sjogren's Syndrome and Sjogren's can cause low C3 and/or C4.

I found this study and thought you might be interested in it as it is about mast cells and allergic reactions related to complement C3 and C4 levels. The results did NOT show a correlation between the patients condition and levels of C3 and C4.
https://clinicalmolecularallergy.biomedcentral.com/articles/10.1186/1476-7961-2-6