Basic Science / Structures > Immune System > Complement

Complement

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classic pathway = antigen-antibody
alternate pathway = contact with bacterial wall lipopolysaccharides etc… (type II and type III reactions)
C3a, C5a = chemotactic factors (for PMNs, eosinophils, and monocytes)
C3b = opsonization
decreased C3  (= active lupus?)

 

 

complement deficiencies:

early components --> autoimmune
late components --> infections

 

Deficiency:Condition:

 

C1 esterase inhibitorhereditary angioedema

 

factor I, C3, factor Dpyogenic infections (abscesses)

 

C5, C6, C7, C8disseminated gonococcemia

 

C5 dysfunctionLeiners disease

 

 

lab finding:Condition:

 

decreased C4hereditary angioedema

 

decreased C1qacquired angioedema

 

decreased C3 and circulating C3 nephritic factorpartial lipodystrophy