complement cascade
A sequential enzymatic pathway of immune proteins that can cause CNS tissue damage when dysregulated.
Full Definition
The complement cascade is a sophisticated enzymatic pathway consisting of over 30 proteins that functions as a key component of innate immunity. In neuroimmunology, complement activation can be both protective and pathological, depending on the context and degree of activation. The cascade proceeds through classical, alternative, and lectin pathways, all converging on the formation of membrane attack complexes (MAC) that can lyse cells. Within the CNS, excessive complement activation contributes to tissue damage in conditions such as neuromyelitis optica, where complement-mediated astrocyte destruction occurs following aquaporin-4 antibody binding. Complement components are also involved in synaptic pruning during normal development and may be dysregulated in neurodegenerative diseases. Understanding complement regulation is crucial for developing targeted therapies in neuroinflammatory conditions.
Usage
Usage note: Specify which complement pathway (classical, alternative, lectin) when discussing specific mechanisms.
In Context
- "Complement cascade activation was evident in the patient's CSF with elevated C3 and C4 consumption." — Laboratory analysis
- "Therapeutic complement cascade inhibition may reduce tissue damage in NMO spectrum disorders." — Treatment discussion