Complement C4a or complement component 4a is a glycoprotein and peptide that is expressed, primarily in the liver and in macrophages, in response to acute inflammation or tissue injury. Complement C4a is part of the Complement C4 family.
The testing for C4a can help determine if a deficiency or abnormality is a contributing factor to increased infections or increased autoimmune activity. The measurement can also be used to monitor autoimmune disorders.
C4a, in conjunction with C3a, may be useful markers in acute and chronic Lyme disease.
Reference Ranges for Complement C4a:
→ Males: 152.0–1559.4 ng/mL
→ Females: 215.7–2025.9 ng/mL
Nijs J, Van Oosterwijck J, Meeus M, Lambrecht L, Metzger K, Frémont M, Paul L. Unravelling the nature of postexertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: the role of elastase, complement C4a and interleukin-1beta. J Intern Med. 2010 Apr;267(4):418-35. doi: 10.1111/j.1365-2796.2009.02178.x. PMID: 20433584.
Ingram G, Hakobyan S, Robertson NP, Morgan BP. Elevated plasma C4a levels in multiple sclerosis correlate with disease activity. J Neuroimmunol. 2010 Jun;223(1-2):124-7. doi: 10.1016/j.jneuroim.2010.03.014. Epub 2010 Apr 20. PMID: 20409594.
Elevation of C4a levels is not predictive of any specific disease.
Complement C4a levels can become increased in any condition associated with inflammation.
→ Normal human pregnancy is associated with evidence of complement activation, with an increase in concentrations of the anaphylatoxins C3a, C4a, and C5a in the maternal circulation.
→ Levels of anaphylatoxins C3a and C4a have also been found to be elevated in patients with antiphospholipid syndrome relative to healthy controls. Antiphospholipid syndrome (APS) is an autoimmune disorder that causes abnormal blood clots to form.
→ Ingram and associates have shown that levels of C4a are increased in patients with multiple sclerosis, especially during relapse. Multiple sclerosis is a disease in which your body's immune system eats away at the protective sheath that covers your nerves. The disorder disrupts communication between your brain and the rest of your body, meaning your nerve signals slow down or stop.
→ Nijs et al. (2010) found a strong relation between the change in complement C4a level and an increase in post-exertional pain and fatigue in ME/CFS patients. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complicated disorder. It causes extreme fatigue that lasts for at least six months.
Own it for life
Our exclusive data entry service is a convenient way to get your results into your private dashboard. Simply attach an image or a file of your lab test results, and one of our qualified data entry team members will add the results for you. We support all sorts of files, whether PDFs, JPGs, or Excel. This service is excellent whether you have a lot of reports to upload or are too busy to do the data entry yourself.
We strive to make the data entry process easy for you. Whether by offering dozens of templates to choose from that pre-populate the most popular laboratory panels or by giving you instant feedback on the entered values. Our data entry forms are an easy, fast, and convenient way to enter the reports yourself. There is no limit on how many lab reports you can upload.
billed every month
Data entry included
$6.60/month billed annually
Data entry included
own it for life
Are You a Health Professional?
Get started with our professional plan
Welcome to Healthmatters Pro.
Save time on interpreting lab results with the largest database of biomarkers online. In-depth research on any test at your fingertips, all stored and tracked in one place. Learn more
Pro Monthly Plus
for health professionals
$75 per month