Terminal complement pathway deficiency is a genetic condition affecting the
complement membrane attack complex
The membrane attack complex (MAC) or terminal complement complex (TCC) is a complex of proteins typically formed on the surface of pathogen cell membranes as a result of the activation of the host's complement system, and as such is an effector ...
(MAC).
It involves deficiencies of
C5,
C6,
C7, and
C8. (While
C9 is part of the MAC, and deficiencies have been identified,
it is not required for cell lysis.
)
People with this condition are prone to
meningococcal
''Neisseria meningitidis'', often referred to as meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a ...
infection.
Vaccination may be recommended.
Cause
Diagnosis
Suspect terminal complement pathway deficiency with patients who have more than one episode of Neisseria infection.
Initial complement tests often include C3 and C4, but not C5 through C9. Instead, the
CH50 result may play a role in diagnosis: if the CH50 level is low but C3 and C4 are normal, then analysis of the individual terminal components may be warranted.
Treatment
Patients with terminal complement pathway deficiency should receive meningococcal and pneumococcal vaccinations. They can receive live vaccines.
References
External links
Complement deficiency
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