Skip to main content

Table 3 Complement as a biomarker for neurodegenerative diseases

From: The good, the bad, and the opportunities of the complement system in neurodegenerative disease

  AD ALS Stroke Epilepsy TBI MS
C1 C1q elevated in plasma enriched for astrocyte-derived exosomes (ADE) early in AD [201] Elevated in serum [82]     C1q elevated in plasma ADE [202]
C4 C4a is elevated in plasma [203], C4b elevated in ADE [201] Elevated in serum [82] C4d elevated in plasma 24 hr after stroke [204] C4 is elevated in patients with uncontrolled seizures vs controlled [205] C4b chronically elevated in plasma ADE in mild TBI [206] C4/C4a increased in plasma and CSF [207, 208]
C3 C3d elevated in ADE [201] C3 Elevated in serum [82]. C3a unchanged in plasma of ALS patients compared with age-matched controls [209] C3a elevated in plasma 1-14 days after stroke and correlated with prognosis [82, 204, 210] Properdin & C3 elevated, iC3b decreased in serum of patients with uncontrolled seizures vs controlled seizures [205, 211] C3b chronically elevated in plasma ADE in mild TBI [206], C3a elevated in serum immediately after injury and remains chronically elevated [212] C3b/iC3b elevated in plasma ADE [202], and in whole plasma [207]. Properdin elevated in CSF [208]
C5   C5a elevated in the plasma of ALS patients [209] C5a elevated in plasma 1-14 days after stroke [82, 204]   Serum C5a increases immediately after injury & continues to rise up to 10 days post injury [212] C5/C5a elevated in plasma ADE [202]
C5b-9 C9 is elevated in plasma [203]. C5b-9 elevated in ADE [201]. sC5b-9 decreased in patients with MCI who later develop AD [213] Elevated in plasma of ALS patients [209] Plasma sC5b-9 is elevated after stroke and increases throughout recovery, but is decreased in mild cases [82, 210, 214] C5b-9 elevated in plasma of patients with focal and generalized seizures, clusterin reduced [205] Elevated in plasma ADE in mild TBI cases for up to 12 years after injury [206, 212] C9 levels reduced in plasma and CSF of MS patients [207]
Inhibitory factors FI decreased in patients with MCI who later develop AD [213, 215]. Clusterin is elevated [217], CD59, CD46, CR1, DAF decreased in ADE [201]    fH elevated in plasma of patients with focal and generalized seizures, clusterin decreased in patients with uncontrolled seizures vs controlled [205] FI, CR1, CD59, C4BP decreased shortly after injury in plasma ADE [206, 212] fH elevated in plasma ADE [202], C1inh and fH elevated in plasma and CSF [207, 208]
Factor B Elevated in ADE [201]      fB reduced in CSF and plasma [207]