Complement C4a

Complement C4a is a glycoprotein and peptide that is expressed, primarily in the liver and in macrophages, in response to acute inflammation or tissue injury. Complement C3 also has a role in allergy response.

ME/CFS
Increased C4a levels have been found one to six hours after exercise challenge tests in ME/CFS patients but not in healthy controls.

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. Previously, complement C4a, in combination with other proteins, was being considered as a potential marker of post-exertional malaise in ME/CFS.

Notable studies

 * 2009, Transcriptional Control of Complement Activation in an Exercise Model of Chronic Fatigue Syndrome (Full text)

Learn more

 * The Role of Anaphylatoxins in Health and Disease