Complement deficiency


Complement deficiency is an immunodeficiency of absent or suboptimal functioning of one of the complement system proteins. Because there are redundancies in the immune system, many complement disorders are never diagnosed, some studies estimated that less than 10% are identified. Hypocomplementemia may be used more generally to refer to decreased complement levels while secondary complement disorder means decreased complement levels that are not directly due to a genetic cause but secondary to another medical condition.

Signs and symptoms

The following symptoms are consistent with complement deficiency in general:

Complications

for encapsulated organisms is crucial for preventing infections in complement deficiencies. Among the possible complications are the following:
The cause of complement deficiency is genetics. The majority of complement deficiencies are autosomal recessive, while properdin deficiency could be X-linked inheritance, and finally MBL deficiency can be both.

Inherited

Acquired hypocomplementemia may occur in the setting of bone infections, infection of the lining of the heart, and cryoglobulinemia. Systemic lupus erythematosus is associated with low C3 and C4 Membranoproliferative glomerulonephritis usually has low C3.

Mechanism

The mechanism of complement deficiency consists of:
Among the diagnostic tests that can be done in determining if an individual has complement deficiencies is:
In terms of management for complement deficiency, immunosuppressive therapy should be used depending on the disease presented. A C1-INH concentrate can be used for angio-oedema.
Pneumococcus and haemophilus infections prevention can be taken via immunization for those with complement deficiency. Epsilon-aminocaproic acid could be used to treat hereditary C1-INH deficiency, though the possible side effect of intravascular thrombosis should be weighed.

Epidemiology

C2 deficiency has a prevalence of 1 in about 20,000 people in Western countries.