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[Hereditary complement deficiencies]
Insights
Complement deficiencies affect all nine components, impacting immunity and disease susceptibility. Defects in early or late complement pathways are linked to autoimmune diseases and severe infections.
Area of Science:
- Immunology
- Genetics
Context:
- The complement system is crucial for innate and adaptive immunity.
- Deficiencies in complement components can arise hereditarily.
- These deficiencies have significant clinical implications.
Purpose:
- To review hereditary complement deficiencies.
- To discuss their genetic basis.
- To explore associated pathomechanisms and clinical manifestations.
Summary:
- Hereditary deficiencies of early complement components (C1, C4, C2) are associated with immune complex diseases like lupus erythematosus, vasculitis, and nephritis.
- Deficiencies in C3 and C3b inactivator lead to severe, recurrent bacterial infections.
- Defects in late components (C5-C9) increase susceptibility to Neisseria infections.
- Hereditary angioneurotic edema is frequently linked to C1-inactivator deficiency.
Impact:
- Understanding complement defects aids in diagnosing and managing autoimmune and infectious diseases.
- Highlights the critical role of the complement system in host defense.
- Provides insights into the genetic basis of immune dysregulation.
Abstract:
Complement deficiencies of all nine C-components have been observed. Hereditary defects of early components of the classical pathway - C1, C4, C2 - are often associated with diseases of the immuncomplex-type especially with systemic lupus erythematosus, dermatomysitis, vasculitis and nephritis. Deficiencies of C3 and C3b inactivator are linked to severe and recurrent bacterial infections. Patients with hereditary defects of the so-called late components, C5-C9, show increased susceptibility to recurrent disseminated infections by neisseria gonorrhoeae and meningitidis. The most frequent of the defects of the complement system is the hereditary deficiency of C1-inactivator which is associated with hereditary angioneurotic edema. In this paper the C-defects and their genetics are described and possible pathomechanisms are discussed.