Component C4 of the complement

General Information

The complement system, that is, the so-called The complement cascade is a component of humoral immunity that enhances the ability of phagocytes and antibodies to remove damaged cells and microbes from the body. Strengthens the ability to attack pathogenic cells and microbes.

The C4 component is part of the complement system, which is mainly synthesized in the lungs and bones. Serum C4 concentration is a sensitive indicator of systemic lupus erythematosus activity.

In congenital angioedema, the lack of enzyme C1-esterase inhibitor leads to increased breakdown of C2 and C4 components, which is why the C4 component serum level is low.

A low level of the C4 component is seen in a condition similar to systemic lupus erythematosus without lupus cells, Schönlein-Henoch purpura, and glomerulonephritis.

Hereditary deficiency of complement C4 component increases the risk of bacterial infections with purulent processes.

When is it held? C4 Component research?

• Suspicion of congenital or acquired deficiency of C4 component associated with immunological disorders: systemic lupus erythematosus, serum sickness, chronic active hepatitis, glomerulonephritis.

• Assessment of systemic lupus erythematosus activity
• To confirm the diagnostics of hereditary angioedema - when the level of enzyme C1-esterase inhibitor is low.

Preparation of the patient: The study is conducted on an empty stomach

Material for examination: Venous blood

Reference boundaries ​​- 10-40 mg/dl

Interpretation of results

Some medications affect the levels of complement components

increases : cyclophosphamide, danazol, oral contraceptives

reduces: dextrans, methyldopa, penicillamine

Monoclonal IgA or IgM type disorders affect C4 determination. Excessive serum lipemia leads to an increase in the C4 component.